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Dr. Carleen Eaton

Dr. Carleen Eaton

Mendelian Genetics

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Table of Contents

Section 1: Chemistry of Life
Elements, Compounds, and Chemical Bonds

56m 18s

Intro
0:00
Elements
0:09
Elements
0:48
Matter
0:55
Naturally Occurring Elements
1:12
Atomic Number and Atomic Mass
2:39
Compounds
3:06
Molecule
3:07
Compounds
3:14
Examples
3:20
Atoms
4:53
Atoms
4:56
Protons, Neutrons, and Electrons
5:29
Isotopes
10:42
Energy Levels of Electrons
13:01
Electron Shells
13:13
Valence Shell
13:22
Example: Electron Shells and Potential Energy
13:28
Covalent Bonds
19:52
Covalent Bonds
19:54
Examples
20:03
Polar and Nonpolar Covalent Bonds
23:54
Polar Bond
24:07
Nonpolar Bonds
24:17
Examples
24:25
Ionic Bonds
29:04
Ionic Bond, Cations, Anions
29:19
Example: NaCl
29:30
Hydrogen Bond
33:18
Hydrogen Bond
33:20
Chemical Reactions
35:36
Example: Reactants, Products and Chemical Reactions
35:45
Molecular Mass and Molar Concentration
38:45
Avogadro's Number and Mol
39:12
Examples: Molecular Mass and Molarity
42:10
Example 1: Proton, Neutrons and Electrons
47:05
Example 2: Reactants and Products
49:35
Example 3: Bonding
52:39
Example 4: Mass
53:59
Properties of Water

50m 23s

Intro
0:00
Molecular Structure of Water
0:21
Molecular Structure of Water
0:27
Properties of Water
4:30
Cohesive
4:55
Transpiration
5:29
Adhesion
6:20
Surface Tension
7:17
Properties of Water, cont.
9:14
Specific Heat
9:25
High Heat Capacity
13:24
High Heat of Evaporation
16:42
Water as a Solvent
21:13
Solution
21:28
Solvent
21:48
Example: Water as a Solvent
22:22
Acids and Bases
25:40
Example
25:41
pH
36:30
pH Scale: Acidic, Neutral, and Basic
36:35
Example 1: Molecular Structure and Properties of Water
41:18
Example 2: Special Properties of Water
42:53
Example 3: pH Scale
44:46
Example 4: Acids and Bases
46:19
Organic Compounds

53m 54s

Intro
0:00
Organic Compounds
0:09
Organic Compounds
0:11
Inorganic Compounds
0:15
Examples: Organic Compounds
1:15
Isomers
5:52
Isomers
5:55
Structural Isomers
6:23
Geometric Isomers
8:14
Enantiomers
9:55
Functional Groups
12:46
Examples: Functional Groups
12:59
Amino Group
13:51
Carboxyl Group
14:38
Hydroxyl Group
15:22
Methyl Group
16:14
Carbonyl Group
16:30
Phosphate Group
17:51
Carbohydrates
18:26
Carbohydrates
19:07
Example: Monosaccharides
21:12
Carbohydrates, cont.
24:11
Disaccharides, Polysaccharides and Examples
24:21
Lipids
35:52
Examples of Lipids
36:04
Saturated and Unsaturated
38:57
Phospholipids
43:26
Phospholipids
43:29
Example
43:34
Steroids
46:24
Cholesterol
46:28
Example 1: Isomers
48:11
Example 2: Functional Groups
50:45
Example 3: Galactose, Ketose, and Aldehyde Sugar
52:24
Example 4: Class of Molecules
53:06
Nucleic Acids and Proteins

37m 23s

Intro
0:00
Nucleic Acids
0:09
Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)
0:29
Nucleic Acids, cont.
2:56
Purines
3:10
Pyrimidines
3:32
Double Helix
4:59
Double Helix and Example
5:01
Proteins
12:33
Amino Acids and Polypeptides
12:39
Examples: Amino Acid
13:25
Polypeptide Formation
18:09
Peptide Bonds
18:14
Primary Structure
18:35
Protein Structure
23:19
Secondary Structure
23:22
Alpha Helices and Beta Pleated Sheets
23:34
Protein Structure
25:43
Tertiary Structure
25:44
5 Types of Interaction
26:56
Example 1: Complementary DNA Strand
31:45
Example 2: Differences Between DNA and RNA
33:19
Example 3: Amino Acids
34:32
Example 4: Tertiary Structure of Protein
35:46
Section 2: Cell Structure and Function
Cell Types (Prokaryotic and Eukaryotic)

45m 50s

Intro
0:00
Cell Theory and Cell Types
0:12
Cell Theory
0:13
Prokaryotic and Eukaryotic Cells
0:36
Endosymbiotic Theory
1:13
Study of Cells
4:07
Tools and Techniques
4:08
Light Microscopes
5:08
Light vs. Electron Microscopes: Magnification
5:18
Light vs. Electron Microscopes: Resolution
6:26
Light vs. Electron Microscopes: Specimens
7:53
Electron Microscopes: Transmission and Scanning
8:28
Cell Fractionation
10:01
Cell Fractionation Step 1: Homogenization
10:33
Cell Fractionation Step 2: Spin
11:24
Cell Fractionation Step 3: Differential Centrifugation
11:53
Comparison of Prokaryotic and Eukaryotic Cells
14:12
Prokaryotic vs. Eukaryotic Cells: Domains
14:43
Prokaryotic vs. Eukaryotic Cells: Plasma Membrane
15:40
Prokaryotic vs. Eukaryotic Cells: Cell Walls
16:15
Prokaryotic vs. Eukaryotic Cells: Genetic Materials
16:38
Prokaryotic vs. Eukaryotic Cells: Structures
17:28
Prokaryotic vs. Eukaryotic Cells: Unicellular and Multicellular
18:19
Prokaryotic vs. Eukaryotic Cells: Size
18:31
Plasmids
18:52
Prokaryotic vs. Eukaryotic Cells
19:22
Nucleus
19:24
Organelles
19:48
Cytoskeleton
20:02
Cell Wall
20:35
Ribosomes
20:57
Size
21:37
Comparison of Plant and Animal Cells
22:15
Plasma Membrane
22:55
Plant Cells Only: Cell Walls
23:12
Plant Cells Only: Central Vacuole
25:08
Animal Cells Only: Centrioles
26:40
Animal Cells Only: Lysosomes
27:43
Plant vs. Animal Cells
29:16
Overview of Plant and Animal Cells
29:17
Evidence for the Endosymbiotic Theory
30:52
Characteristics of Mitochondria and Chloroplasts
30:54
Example 1: Prokaryotic vs. Eukaryotic Cells
35:44
Example 2: Endosymbiotic Theory and Evidence
38:38
Example 3: Plant and Animal Cells
41:49
Example 4: Cell Fractionation
43:44
Subcellular Structure

59m 38s

Intro
0:00
Prokaryotic Cells
0:09
Shapes of Prokaryotic Cells
0:22
Cell Wall
1:19
Capsule
3:23
Pili/Fimbria
3:54
Flagella
4:35
Nucleoid
6:16
Plasmid
6:37
Ribosomes
7:09
Eukaryotic Cells (Animal Cell Structure)
8:01
Plasma Membrane
8:13
Microvilli
8:48
Nucleus
9:47
Nucleolus
11:06
Ribosomes: Free and Bound
12:26
Rough Endoplasmic Reticulum (RER)
13:43
Eukaryotic Cells (Animal Cell Structure), cont.
14:51
Endoplasmic Reticulum: Smooth and Rough
15:08
Golgi Apparatus
17:55
Vacuole
20:43
Lysosome
22:01
Mitochondria
25:40
Peroxisomes
28:18
Cytoskeleton
30:41
Cytoplasm and Cytosol
30:53
Microtubules: Centrioles, Spindel Fibers, Clagell, Cillia
32:06
Microfilaments
36:39
Intermediate Filaments and Kerotin
38:52
Eukaryotic Cells (Plant Cell Structure)
40:08
Plasma Membrane, Primary Cell Wall, and Secondary Cell Wall
40:30
Middle Lamella
43:21
Central Cauole
44:12
Plastids: Leucoplasts, Chromoplasts, Chrloroplasts
45:35
Chloroplasts
47:06
Example 1: Structures and Functions
48:46
Example 2: Cell Walls
51:19
Example 3: Cytoskeleton
52:53
Example 4: Antibiotics and the Endosymbiosis Theory
56:55
Cell Membranes and Transport

53m 10s

Intro
0:00
Cell Membrane Structure
0:09
Phospholipids Bilayer
0:11
Chemical Structure: Amphipathic and Fatty Acids
0:25
Cell Membrane Proteins
2:44
Fluid Mosaic Model
2:45
Peripheral Proteins and Integral Proteins
3:19
Transmembrane Proteins
4:34
Cholesterol
4:48
Functions of Membrane Proteins
6:39
Transport Across Cell Membranes
9:52
Transport Across Cell Membranes
9:53
Methods of Passive Transport
12:07
Passive and Active Transport
12:08
Simple Diffusion
12:45
Facilitated Diffusion
15:20
Osmosis
17:17
Definition and Example of Osmosis
17:18
Hypertonic, Hypotonic, and Isotonic
21:47
Active Transport
27:57
Active Transport
28:17
Sodium and Potassium Pump
29:45
Cotransport
34:38
2 Types of Active Transport
37:09
Endocytosis and Exocytosis
37:38
Endocytosis and Exocytosis
37:51
Types of Endocytosis: Pinocytosis
40:39
Types of Endocytosis: Phagocytosis
41:02
Receptor Mediated Endocytosis
41:27
Receptor Mediated Endocytosis
41:28
Example 1: Cell Membrane and Permeable Substances
43:59
Example 2: Osmosis
45:20
Example 3: Active Transport, Cotransport, Simple and Facilitated Diffusion
47:36
Example 4: Match Terms with Definition
50:55
Cellular Communication

57m 9s

Intro
0:00
Extracellular Matrix
0:28
The Extracellular Matrix (ECM)
0:29
ECM in Animal Cells
0:55
Fibronectin and Integrins
1:34
Intercellular Communication in Plants
2:48
Intercellular Communication in Plants: Plasmodesmata
2:50
Cell to Cell Communication in Animal Cells
3:39
Cell Junctions
3:42
Desmosomes
3:54
Tight Junctions
5:07
Gap Junctions
7:00
Cell Signaling
8:17
Cell Signaling: Ligand and Signal Transduction Pathway
8:18
Direct Contact
8:48
Over Distances Contact and Hormones
10:09
Stages of Cell Signaling
11:53
Reception Phase
11:54
Transduction Phase
13:49
Response Phase
14:45
Cell Membrane Receptors
15:37
G-Protein Coupled Receptor
15:38
Cell Membrane Receptor, Cont.
21:37
Receptor Tyrosine Kinases (RTKs)
21:38
Autophosphorylation, Monomer, and Dimer
22:57
Cell Membrane Receptor, Cont.
27:01
Ligand-Gated Ion Channels
27:02
Intracellular Receptors
29:43
Intracellular Receptor and Receptor -Ligand Complex
29:44
Signal Transduction
32:57
Signal Transduction Pathways
32:58
Adenylyl Cyclase and cAMP
35:53
Second Messengers
39:18
cGMP, Inositol Trisphosphate, and Diacylglycerol
39:20
Cell Response
45:15
Cell Response
45:16
Apoptosis
46:57
Example 1: Tight Junction and Gap Junction
48:29
Example 2: Three Phases of Cell Signaling
51:48
Example 3: Ligands and Binding of Hormone
54:03
Example 4: Signal Transduction
56:06
Section 3: Cell Division
The Cell Cycle

37m 49s

Intro
0:00
Functions of Cell Division
0:09
Overview of Cell Division: Reproduction, Growth, and Repair
0:11
Important Term: Daughter Cells
2:25
Chromosome Structure
3:36
Chromosome Structure: Sister Chromatids and Centromere
3:37
Chromosome Structure: Chromatin
4:31
Chromosome with One Chromatid or Two Chromatids
5:25
Chromosome Structure: Long and Short Arm
6:49
Mitosis and Meiosis
7:00
Mitosis
7:41
Meiosis
8:40
The Cell Cycle
10:43
Mitotic Phase and Interphase
10:44
Cytokinesis
15:51
Cytokinesis in Animal Cell: Cleavage Furrow
15:52
Cytokinesis in Plant Cell: Cell Plate
17:28
Control of the Cell Cycle
18:28
Cell Cycle Control System and Checkpoints
18:29
Cyclins and Cyclin Dependent Kinases
21:18
Cyclins and Cyclin Dependent Kinases (CDKSs)
21:20
MPF
23:17
Internal Factor Regulating Cell Cycle
24:00
External Factor Regulating Cell Cycle
24:53
Contact Inhibition and Anchorage Dependent
25:53
Cancer and the Cell Cycle
27:42
Cancer Cells
27:46
Example1: Parts of the Chromosome
30:15
Example 2: Cell Cycle
31:50
Example 3: Control of the Cell Cycle
33:32
Example 4: Cancer and the Cell
35:01
Mitosis

35m 1s

Intro
0:00
Review of the Cell Cycle
0:09
Interphase: G1 Phase
0:34
Interphase: S Phase
0:56
Interphase: G2 Phase
1:31
M Phase: Mitosis and Cytokinesis
1:47
Overview of Mitosis
3:08
What is Mitosis?
3:10
Overview of Mitosis
3:17
Diploid and Haploid
5:37
Homologous Chromosomes
6:04
The Spindle Apparatus
11:57
The Spindle Apparatus
12:00
Centrosomes and Centrioles
12:40
Microtubule Organizing Center
13:03
Spindle Fiber of Spindle Microtubules
13:23
Kinetochores
14:06
Asters
15:45
Prophase
16:47
First Phase of Mitosis: Prophase
16:54
Metaphase
20:05
Second Phase of Mitosis: Metaphase
20:10
Anaphase
22:52
Third Phase of Mitosis: Anaphase
22:53
Telophase and Cytokinesis
24:34
Last Phase of Mitosis: Telophase and Cytokinesis
24:35
Summary of Mitosis
27:46
Summary of Mitosis
27:47
Example 1: Spindle Apparatus
28:50
Example 2: Last Phase of Mitosis
30:39
Example 3: Prophase
32:41
Example 4: Identify the Phase
33:52
Meiosis

1h 58s

Intro
0:00
Haploid and Diploid Cells
0:09
Diploid and Somatic Cells
0:29
Haploid and Gametes
1:20
Example: Human Cells and Chromosomes
1:41
Sex Chromosomes
6:00
Comparison of Mitosis and Meiosis
10:42
Mitosis Vs. Meiosis: Cell Division
10:59
Mitosis Vs. Meiosis: Daughter Cells
12:31
Meiosis: Pairing of Homologous Chromosomes
13:40
Mitosis and Meiosis
14:21
Process of Mitosis
14:27
Process of Meiosis
16:12
Synapsis and Crossing Over
19:14
Prophase I: Synapsis and Crossing Over
19:15
Chiasmata
22:33
Meiosis I
25:49
Prophase I: Crossing Over
25:50
Metaphase I: Homologs Line Up
26:00
Anaphase I: Homologs Separate
28:16
Telophase I and Cytokinesis
29:15
Independent Assortment
30:58
Meiosis II
32:17
Propphase II
33:50
Metaphase II
34:06
Anaphase II
34:50
Telophase II
36:09
Cytokinesis
37:00
Summary of Meiosis
38:15
Summary of Meiosis
38:16
Cell Division Mechanism in Plants
41:57
Example 1: Cell Division and Meiosis
46:15
Example 2: Phases of Meiosis
50:22
Example 3: Label the Figure
54:29
Example 4: Four Differences Between Mitosis and Meiosis
56:37
Section 4: Cellular Energetics
Enzymes

51m 3s

Intro
0:00
Law of Thermodynamics
0:08
Thermodynamics
0:09
The First Law of Thermodynamics
0:37
The Second Law of Thermodynamics
1:24
Entropy
1:35
The Gibbs Free Energy Equation
3:07
The Gibbs Free Energy Equation
3:08
ATP
8:23
Adenosine Triphosphate (ATP)
8:24
Cellular Respiration
11:32
Catabolic Pathways
12:28
Anabolic Pathways
12:54
Enzymes
14:31
Enzymes
14:32
Enzymes and Exergonic Reaction
14:40
Enzymes and Endergonic Reaction
16:36
Enzyme Specificity
21:29
Substrate
21:41
Induced Fit
23:04
Factors Affecting Enzyme Activity
25:55
Substrate Concentration
26:07
pH
27:10
Temperature
29:14
Presence of Cofactors
29:57
Regulation of Enzyme Activity
31:12
Competitive Inhibitors
32:13
Noncompetitive Inhibitors
33:52
Feedback Inhibition
35:22
Allosteric Interactions
36:56
Allosteric Regulators
37:00
Example 1: Is the Inhibitor Competitive or Noncompetitive?
40:49
Example 2: Thermophiles
44:18
Example 3: Exergonic or Endergonic
46:09
Example 4: Energy Vs. Reaction Progress Graph
48:47
Glycolysis and Anaerobic Respiration

38m 1s

Intro
0:00
Cellular Respiration Overview
0:13
Cellular Respiration
0:14
Anaerobic Respiration vs. Aerobic Respiration
3:50
Glycolysis Overview
4:48
Overview of Glycolysis
4:50
Glycolysis Involves a Redox Reaction
7:02
Redox Reaction
7:04
Glycolysis
15:04
Important Facts About Glycolysis
15:07
Energy Invested Phase
16:12
Splitting of Fructose 1,6-Phosphate and Energy Payoff Phase
17:50
Substrate Level Phophorylation
22:12
Aerobic Versus Anaerobic Respiration
23:57
Aerobic Versus Anaerobic Respiration
23:58
Cellular Respiration Overview
27:15
When Cellular Respiration is Anaerobic
27:17
Glycolysis
28:26
Alcohol Fermentation
28:45
Lactic Acid Fermentation
29:58
Example 1: Glycolysis
31:04
Example 2: Glycolysis, Fermentation and Anaerobic Respiration
33:44
Example 3: Aerobic Respiration Vs. Anaerobic Respiration
35:25
Example 4: Exergonic Reaction and Endergonic Reaction
36:42
Aerobic Respiration

51m 6s

Intro
0:00
Aerobic Vs. Anaerobic Respiration
0:06
Aerobic and Anaerobic Comparison
0:07
Review of Glycolysis
1:48
Overview of Glycolysis
2:06
Glycolysis: Energy Investment Phase
2:25
Glycolysis: Energy Payoff Phase
2:58
Conversion of Pyruvate to Acetyl CoA
4:55
Conversion of Pyruvate to Acetyl CoA
4:56
Energy Formation
8:06
Mitochondrial Structure
8:58
Endosymbiosis Theory
9:23
Matrix
10:00
Outer Membrane, Inner Membrane, and Intermembrane Space
10:43
Cristae
11:47
The Citric Acid Cycle
12:11
The Citric Acid Cycle (Also Called Krebs Cycle)
12:12
Substrate Level Phosphorylation
18:47
Summary of ATP, NADH, and FADH2 Production
23:13
Process: Glycolysis
23:28
Process: Acetyl CoA Production
23:36
Process: Citric Acid Cycle
23:52
The Electron Transport Chain
24:24
Oxidative Phosphorylation
24:28
The Electron Transport Chain and ATP Synthase
25:20
Carrier Molecules: Cytochromes
27:18
Carrier Molecules: Flavin Mononucleotide (FMN)
28:05
Chemiosmosis
32:46
The Process of Chemiosmosis
32:47
Summary of ATP Produced by Aerobic Respiration
38:24
ATP Produced by Aerobic Respiration
38:27
Example 1: Aerobic Respiration
43:38
Example 2: Label the Location for Each Process and Structure
45:08
Example 3: The Electron Transport Chain
47:06
Example 4: Mitochondrial Inner Membrane
48:38
Photosynthesis

1h 2m 52s

Intro
0:00
Photosynthesis
0:09
Introduction to Photosynthesis
0:10
Autotrophs and Heterotrophs
0:25
Overview of Photosynthesis Reaction
1:05
Leaf Anatomy and Chloroplast Structure
2:54
Chloroplast
2:55
Cuticle
3:16
Upper Epidermis
3:27
Mesophyll
3:40
Stomates
4:00
Guard Cells
4:45
Transpiration
5:01
Vascular Bundle
5:20
Stroma and Double Membrane
6:20
Grana
7:17
Thylakoids
7:30
Dark Reaction and Light Reaction
7:46
Light Reactions
8:43
Light Reactions
8:47
Pigments: Chlorophyll a, Chlorophyll b, and Carotenoids
9:19
Wave and Particle
12:10
Photon
12:34
Photosystems
13:24
Photosystems
13:28
Reaction-Center Complex and Light Harvesting Complexes
14:01
Noncyclic Photophosphorylation
17:46
Noncyclic Photophosphorylation Overview
17:47
What is Photophosphorylation?
18:25
Noncyclic Photophosphorylation Process
19:07
Photolysis and The Rest of Noncyclic Photophosphorylation
21:33
Cyclic Photophosphorylation
31:45
Cyclic Photophosphorylation
31:46
Light Independent Reactions
34:34
The Calvin Cycle
34:35
C3 Plants and Photorespiration
40:31
C3 Plants and Photorespiration
40:32
C4 Plants
45:32
C4 Plants: Structures and Functions
45:33
CAM Plants
50:25
CAM Plants: Structures and Functions
50:35
Example 1: Calvin Cycle
54:34
Example 2: C4 Plant
55:48
Example 3: Photosynthesis and Photorespiration
58:35
Example 4: CAM Plants
1:00:41
Section 5: Molecular Genetics
DNA Synthesis

38m 45s

Intro
0:00
Review of DNA Structure
0:09
DNA Molecules
0:10
Nitrogenous Base: Pyrimidines and Purines
1:25
DNA Double Helix
3:03
Complementary Strands of DNA
3:12
5' to 3' & Antiparallel
4:55
Overview of DNA Replication
7:10
DNA Replication & Semiconservative
7:11
DNA Replication
10:26
Origin of Replication
10:28
Helicase
11:10
Single-Strand Binding Protein
12:05
Topoisomerases
13:14
DNA Polymerase
14:26
Primase
15:55
Leading and Lagging Strands
16:51
Leading Strand and Lagging Strand
16:52
Okazaki Fragments
18:10
DNA Polymerase I
20:11
Ligase
21:12
Proofreading and Mismatch Repair
22:18
Proofreading
22:19
Mismatch
23:33
Telomeres
24:58
Telomeres
24:59
Example 1: Function of Enzymes During DNA Synthesis
28:09
Example 2: Accuracy of the DNA Sequence
31:42
Example 3: Leading Strand and Lagging Strand
32:38
Example 4: Telomeres
35:40
Transcription and Translation

1h 17m 1s

Intro
0:00
Transcription and Translation Overview
0:07
From DNA to RNA to Protein
0:09
Structure and Types of RNA
3:14
Structure and Types of RNA
3:33
mRNA
6:19
rRNA
7:02
tRNA
7:28
Transcription
7:54
Initiation Phase
8:11
Elongation Phase
12:12
Termination Phase
14:51
RNA Processing
16:11
Types of RNA Processing
16:12
Exons and Introns
16:35
Splicing & Spliceosomes
18:27
Addition of a 5' Cap and a Poly A tail
20:41
Alternative Splicing
21:43
Translation
23:41
Nucleotide Triplets or Codons
23:42
Start Codon
25:24
Stop Codons
25:38
Coding of Amino Acids and Wobble Position
25:57
Translation Cont.
28:29
Transfer RNA (tRNA): Structures and Functions
28:30
Ribosomes
35:15
Peptidyl, Aminoacyl, and Exit Site
35:23
Steps of Translation
36:58
Initiation Phase
37:12
Elongation Phase
43:12
Termination Phase
45:28
Mutations
49:43
Types of Mutations
49:44
Substitutions: Silent
51:11
Substitutions: Missense
55:27
Substitutions: Nonsense
59:37
Insertions and Deletions
1:01:10
Example 1: Three Types of Processing that are Performed on pre-mRNA
1:06:53
Example 2: The Process of Translation
1:09:10
Example 3: Transcription
1:12:04
Example 4: Three Types of Substitution Mutations
1:14:09
Viral Structure and Genetics

43m 12s

Intro
0:00
Structure of Viruses
0:09
Structure of Viruses: Capsid and Envelope
0:10
Bacteriophage
1:48
Other Viruses
2:28
Overview of Viral Reproduction
3:15
Host Range
3:48
Step 1: Bind to Host Cell
4:39
Step 2: Viral Nuclei Acids Enter the Cell
5:15
Step 3: Viral Nucleic Acids & Proteins are Synthesized
5:54
Step 4: Virus Assembles
6:34
Step 5: Virus Exits the Cell
6:55
The Lytic Cycle
7:37
Steps in the Lytic Cycle
7:38
The Lysogenic Cycle
11:27
Temperate Phage
11:34
Steps in the Lysogenic Cycle
12:09
RNA Viruses
16:57
Types of RNA Viruses
17:15
Positive Sense
18:16
Negative Sense
18:48
Reproductive Cycle of RNA Viruses
19:32
Retroviruses
25:48
Complementary DNA (cDNA) & Reverse Transcriptase
25:49
Life Cycle of a Retrovirus
28:22
Prions
32:42
Prions: Definition and Examples
32:45
Viroids
34:46
Example 1: The Lytic Cycle
35:37
Example 2: Retrovirus
38:03
Example 3: Positive Sense RNA vs. Negative Sense RNA
39:10
Example 4: The Lysogenic Cycle
40:42
Bacterial Genetics and Gene Regulation

49m 45s

Intro
0:00
Bacterial Genomes
0:09
Structure of Bacterial Genomes
0:16
Transformation
1:22
Transformation
1:23
Vector
2:49
Transduction
3:32
Process of Transduction
3:38
Conjugation
8:06
Conjugation & F factor
8:07
Operons
14:02
Definition and Example of Operon
14:52
Structural Genes
16:23
Promoter Region
17:04
Regulatory Protein & Operators
17:53
The lac Operon
20:09
The lac Operon: Inducible System
20:10
The trp Operon
28:02
The trp Operon: Repressible System
28:03
Corepressor
31:37
Anabolic & Catabolic
33:12
Positive Regulation of the lac Operon
34:39
Positive Regulation of the lac Operon
34:40
Example 1: The Process of Transformation
39:07
Example 2: Operon & Terms
43:29
Example 3: Inducible lac Operon and Repressible trp Operon
45:15
Example 4: lac Operon
47:10
Eukaryotic Gene Regulation and Mobile Genetic Elements

54m 26s

Intro
0:00
Mechanism of Gene Regulation
0:11
Differential Gene Expression
0:13
Levels of Regulation
2:24
Chromatin Structure and Modification
4:35
Chromatin Structure
4:36
Levels of Packing
5:50
Euchromatin and Heterochromatin
8:58
Modification of Chromatin Structure
9:58
Epigenetic
12:49
Regulation of Transcription
14:20
Promoter Region, Exon, and Intron
14:26
Enhancers: Control Element
15:31
Enhancer & DNA-Bending Protein
17:25
Coordinate Control
21:23
Silencers
23:01
Post-Transcriptional Regulation
24:05
Post-Transcriptional Regulation
24:07
Alternative Splicing
27:19
Differences in mRNA Stability
28:02
Non-Coding RNA Molecules: micro RNA & siRNA
30:01
Regulation of Translation and Post-Translational Modifications
32:31
Regulation of Translation and Post-Translational Modifications
32:55
Ubiquitin
35:21
Proteosomes
36:04
Transposons
37:50
Mobile Genetic Elements
37:56
Barbara McClintock
38:37
Transposons & Retrotransposons
40:38
Insertion Sequences
43:14
Complex Transposons
43:58
Example 1: Four Mechanisms that Decrease Production of Protein
45:13
Example 2: Enhancers and Gene Expression
49:09
Example 3: Primary Transcript
50:41
Example 4: Retroviruses and Retrotransposons
52:11
Biotechnology

49m 26s

Intro
0:00
Definition of Biotechnology
0:08
Biotechnology
0:09
Genetic Engineering
1:05
Example: Golden Corn
1:57
Recombinant DNA
2:41
Recombinant DNA
2:42
Transformation
3:24
Transduction
4:24
Restriction Enzymes, Restriction Sites, & DNA Ligase
5:32
Gene Cloning
13:48
Plasmids
14:20
Gene Cloning: Step 1
17:35
Gene Cloning: Step 2
17:57
Gene Cloning: Step 3
18:53
Gene Cloning: Step 4
19:46
Gel Electrophoresis
27:25
What is Gel Electrophoresis?
27:26
Gel Electrophoresis: Step 1
28:13
Gel Electrophoresis: Step 2
28:24
Gel Electrophoresis: Step 3 & 4
28:39
Gel Electrophoresis: Step 5
29:55
Southern Blotting
31:25
Polymerase Chain Reaction (PCR)
32:11
Polymerase Chain Reaction (PCR)
32:12
Denaturing Phase
35:40
Annealing Phase
36:07
Elongation/ Extension Phase
37:06
DNA Sequencing and the Human Genome Project
39:19
DNA Sequencing and the Human Genome Project
39:20
Example 1: Gene Cloning
40:40
Example 2: Recombinant DNA
43:04
Example 3: Match Terms With Descriptions
45:43
Example 4: Polymerase Chain Reaction
47:36
Section 6: Heredity
Mendelian Genetics

1h 32m 8s

Intro
0:00
Background
0:40
Gregory Mendel & Mendel's Law
0:41
Blending Hypothesis
1:04
Particulate Inheritance
2:08
Terminology
2:55
Gene
3:05
Locus
3:57
Allele
4:37
Dominant Allele
5:48
Recessive Allele
7:38
Genotype
9:22
Phenotype
10:01
Homozygous
10:44
Heterozygous
11:39
Penetrance
11:57
Expressivity
14:15
Mendel's Experiments
15:31
Mendel's Experiments: Pea Plants
15:32
The Law of Segregation
21:16
Mendel's Conclusions
21:17
The Law of Segregation
22:57
Punnett Squares
28:27
Using Punnet Squares
28:30
The Law of Independent Assortment
32:35
Monohybrid
32:38
Dihybrid
33:29
The Law of Independent Assortment
34:00
The Law of Independent Assortment, cont.
38:13
The Law of Independent Assortment: Punnet Squares
38:29
Meiosis and Mendel's Laws
43:38
Meiosis and Mendel's Laws
43:39
Test Crosses
49:07
Test Crosses Example
49:08
Probability: Multiplication Rule and the Addition Rule
53:39
Probability Overview
53:40
Independent Events & Multiplication Rule
55:40
Mutually Exclusive Events & Addition Rule
1:00:25
Incomplete Dominance, Codominance and Multiple Alleles
1:02:55
Incomplete Dominance
1:02:56
Incomplete Dominance, Codominance and Multiple Alleles
1:07:06
Codominance and Multiple Alleles
1:07:08
Polygenic Inheritance and Pleoitropy
1:10:19
Polygenic Inheritance and Pleoitropy
1:10:26
Epistasis
1:12:51
Example of Epistasis
1:12:52
Example 1: Genetic of Eye Color and Height
1:17:39
Example 2: Blood Type
1:21:57
Example 3: Pea Plants
1:25:09
Example 4: Coat Color
1:28:34
Linked Genes and Non-Mendelian Modes of Inheritance

39m 38s

Intro
0:00
Review of the Law of Independent Assortment
0:14
Review of the Law of Independent Assortment
0:24
Linked Genes
6:06
Linked Genes
6:07
Bateson & Pannett: Pea Plants
8:00
Crossing Over and Recombination
15:17
Crossing Over and Recombination
15:18
Extranuclear Genes
20:50
Extranuclear Genes
20:51
Cytoplasmic Genes
21:31
Genomic Imprinting
23:45
Genomic Imprinting
23:58
Methylation
24:43
Example 1: Recombination Frequencies & Linkage Map
27:07
Example 2: Linked Genes
28:39
Example 3: Match Terms to Correct Descriptions
36:46
Example 4: Leber's Optic Neuropathy
38:40
Sex-Linked Traits and Pedigree Analysis

43m 39s

Intro
0:00
Sex-Linked Traits
0:09
Human Chromosomes, XY, and XX
0:10
Thomas Morgan's Drosophila
1:44
X-Inactivation and Barr Bodies
14:48
X-Inactivation Overview
14:49
Calico Cats Example
17:04
Pedigrees
19:24
Definition and Example of Pedigree
19:25
Autosomal Dominant Inheritance
20:51
Example: Huntington's Disease
20:52
Autosomal Recessive Inheritance
23:04
Example: Cystic Fibrosis, Tay-Sachs Disease, and Phenylketonuria
23:05
X-Linked Recessive Inheritance
27:06
Example: Hemophilia, Duchene Muscular Dystrohpy, and Color Blindess
27:07
Example 1: Colorblind
29:48
Example 2: Pedigree
37:07
Example 3: Inheritance Pattern
39:54
Example 4: X-inactivation
41:17
Section 7: Evolution
Natural Selection

1h 3m 28s

Intro
0:00
Background
0:09
Work of Other Scientists
0:15
Aristotle
0:43
Carl Linnaeus
1:32
George Cuvier
2:47
James Hutton
4:10
Thomas Malthus
5:05
Jean-Baptiste Lamark
5:45
Darwin's Theory of Natural Selection
7:50
Evolution
8:00
Natural Selection
8:43
Charles Darwin & The Galapagos Islands
10:20
Genetic Variation
20:37
Mutations
20:38
Independent Assortment
21:04
Crossing Over
24:40
Random Fertilization
25:26
Natural Selection and the Peppered Moth
26:37
Natural Selection and the Peppered Moth
26:38
Types of Natural Selection
29:52
Directional Selection
29:55
Stabilizing Selection
32:43
Disruptive Selection
34:21
Sexual Selection
36:18
Sexual Dimorphism
37:30
Intersexual Selection
37:57
Intrasexual Selection
39:20
Evidence for Evolution
40:55
Paleontology: Fossil Record
41:30
Biogeography
45:35
Continental Drift
46:06
Pangaea
46:28
Marsupials
47:11
Homologous and Analogous Structure
50:10
Homologous Structure
50:12
Analogous Structure
53:21
Example 1: Genetic Variation & Natural Selection
56:15
Example 2: Types of Natural Selection
58:07
Example 3: Mechanisms By Which Genetic Variation is Maintained Within a Population
1:00:12
Example 4: Difference Between Homologous and Analogous Structures
1:01:28
Population Genetic and Evolution

53m 22s

Intro
0:00
Review of Natural Selection
0:12
Review of Natural Selection
0:13
Genetic Drift and Gene Flow
4:40
Definition of Genetic Drift
4:41
Example of Genetic Drift: Cholera Epidemic
5:15
Genetic Drift: Founder Effect
7:28
Genetic Drift: Bottleneck Effect
10:27
Gene Flow
13:00
Quantifying Genetic Variation
14:32
Average Heterozygosity
15:08
Nucleotide Variation
17:05
Maintaining Genetic Variation
18:12
Heterozygote Advantage
19:45
Example of Heterozygote Advantage: Sickle Cell Anemia
20:21
Diploidy
23:44
Geographic Variation
26:54
Frequency Dependent Selection and Outbreeding
28:15
Neutral Traits
30:55
The Hardy-Weinberg Equilibrium
31:11
The Hardy-Weinberg Equilibrium
31:49
The Hardy-Weinberg Conditions
32:42
The Hardy-Weinberg Equation
34:05
The Hardy-Weinberg Example
36:33
Example 1: Match Terms to Descriptions
42:28
Example 2: The Hardy-Weinberg Equilibrium
44:31
Example 3: The Hardy-Weinberg Equilibrium
49:10
Example 4: Maintaining Genetic Variation
51:30
Speciation and Patterns of Evolution

51m 2s

Intro
0:00
Early Life on Earth
0:08
Early Earth
0:09
1920's Oparin & Haldane
0:58
Abiogenesis
2:15
1950's Miller & Urey
2:45
Ribozymes
5:34
3.5 Billion Years Ago
6:39
2.5 Billion Years Ago
7:14
1.5 Billion Years Ago
7:41
Endosymbiosis
8:00
540 Million Years Ago: Cambrian Explosion
9:57
Gradualism and Punctuated Equilibrium
11:46
Gradualism
11:47
Punctuated Equilibrium
12:45
Adaptive Radiation
15:08
Adaptive Radiation
15:09
Example of Adaptive Radiation: Galapogos Islands
17:11
Convergent Evolution, Divergent Evolution, and Coevolution
18:30
Convergent Evolution
18:39
Divergent Evolution
21:30
Coevolution
23:49
Speciation
26:27
Definition and Example of Species
26:29
Reproductive Isolation: Prezygotive
27:49
Reproductive Isolation: Post zygotic
29:28
Allopatric Speciation
30:21
Allopatric Speciation & Geographic Isolation
30:28
Genetic Drift
31:31
Sympatric Speciation
34:10
Sympatric Speciation
34:11
Polyploidy & Autopolyploidy
35:12
Habitat Isolation
39:17
Temporal Isolation
41:27
Selection Selection
41:40
Example 1: Pattern of Evolution
42:53
Example 2: Sympatric Speciation
45:16
Example 3: Patterns of Evolution
48:08
Example 4: Patterns of Evolution
49:27
Section 8: Diversity of Life
Classification

1h 51s

Intro
0:00
Systems of Classification
0:07
Taxonomy
0:08
Phylogeny
1:04
Phylogenetics Tree
1:44
Cladistics
3:37
Classification of Organisms
5:31
Example of Carl Linnaeus System
5:32
Domains
9:26
Kingdoms: Monera, Protista, Plantae, Fungi, Animalia
9:27
Monera
10:06
Phylogentics Tree: Eurkarya, Bacteria, Archaea
11:58
Domain Eukarya
12:50
Domain Bacteria
15:43
Domain Bacteria
15:46
Pathogens
16:41
Decomposers
18:00
Domain Archaea
19:43
Extremophiles Archaea: Thermophiles and Halophiles
19:44
Methanogens
20:58
Phototrophs, Autotrophs, Chemotrophs and Heterotrophs
24:40
Phototrophs and Chemotrophs
25:02
Autotrophs and Heterotrophs
26:54
Photoautotrophs
28:50
Photoheterotrophs
29:28
Chemoautotrophs
30:06
Chemoheterotrophs
31:37
Domain Eukarya
32:40
Domain Eukarya
32:43
Plant Kingdom
34:28
Protists
35:48
Fungi Kingdom
37:06
Animal Kingdom
38:35
Body Symmetry
39:25
Lack Symetry
39:40
Radial Symmetry: Sea Aneome
40:15
Bilateral Symmetry
41:55
Cephalization
43:29
Germ Layers
44:54
Diploblastic Animals
45:18
Triploblastic Animals
45:25
Ectoderm
45:36
Endoderm
46:07
Mesoderm
46:41
Coelomates
47:14
Coelom
47:15
Acoelomate
48:22
Pseudocoelomate
48:59
Coelomate
49:31
Protosomes
50:46
Deuterosomes
51:20
Example 1: Domains
53:01
Example 2: Match Terms with Descriptions
56:00
Example 3: Kingdom Monera and Domain Archaea
57:50
Example 4: System of Classification
59:37
Bacteria

36m 46s

Intro
0:00
Comparison of Domain Archaea and Domain Bacteria
0:08
Overview of Archaea and Bacteria
0:09
Archaea vs. Bacteria: Nucleus, Organelles, and Organization of Genetic Material
1:45
Archaea vs. Bacteria: Cell Walls
2:20
Archaea vs. Bacteria: Number of Types of RNA Pol
2:29
Archaea vs. Bacteria: Membrane Lipids
2:53
Archaea vs. Bacteria: Introns
3:33
Bacteria: Pathogen
4:03
Bacteria: Decomposers and Fix Nitrogen
5:18
Bacteria: Aerobic, Anaerobic, Strict Anaerobes & Facultative Anaerobes
6:02
Phototrophs, Autotrophs, Heterotrophs and Chemotrophs
7:14
Phototrophs and Chemotrophs
7:50
Autotrophs and Heterotrophs
8:53
Photoautotrophs and Photoheterotrophs
10:15
Chemoautotroph and Chemoheterotrophs
11:07
Structure of Bacteria
12:21
Shapes: Cocci, Bacilli, Vibrio, and Spirochetes
12:26
Structures: Plasma Membrane and Cell Wall
14:23
Structures: Nucleoid Region, Plasmid, and Capsule Basal Apparatus, and Filament
15:30
Structures: Flagella, Basal Apparatus, Hook, and Filament
16:36
Structures: Pili, Fimbrae and Ribosome
18:00
Peptidoglycan: Gram + and Gram -
18:50
Bacterial Genomes and Reproduction
21:14
Bacterial Genomes
21:21
Reproduction of Bacteria
22:13
Transformation
23:26
Vector
24:34
Competent
25:15
Conjugation
25:53
Conjugation: F+ and R Plasmids
25:55
Example 1: Species
29:41
Example 2: Bacteria and Exchange of Genetic Material
32:31
Example 3: Ways in Which Bacteria are Beneficial to Other Organisms
33:48
Example 4: Domain Bacteria vs. Domain Archaea
34:53
Protists

1h 18m 48s

Intro
0:00
Classification of Protists
0:08
Classification of Protists
0:09
'Plant-like' Protists
2:06
'Animal-like' Protists
3:19
'Fungus-like' Protists
3:57
Serial Endosymbiosis Theory
5:15
Endosymbiosis Theory
5:33
Photosynthetic Protists
7:33
Life Cycles with a Diploid Adult
13:35
Life Cycles with a Diploid Adult
13:56
Life Cycles with a Haploid Adult
15:31
Life Cycles with a Haploid Adult
15:32
Alternation of Generations
17:22
Alternation of Generations: Multicellular Haploid & Diploid Phase
17:23
Plant-Like Protists
19:58
Euglenids
20:43
Dino Flagellates
22:57
Diatoms
26:07
Plant-Like Protists
28:44
Golden Algae
28:45
Brown Algeas
30:05
Plant-Like Protists
33:38
Red Algae
33:39
Green Algae
35:36
Green Algae: Chlamydomonus
37:44
Animal-Like Protists
40:04
Animal-Like Protists Overview
40:05
Sporozoans (Apicomplexans)
40:32
Alveolates
41:41
Sporozoans (Apicomplexans): Plasmodium & Malaria
42:59
Animal-Like Protists
48:44
Kinetoplastids
48:50
Example of Kinetoplastids: Trypanosomes & African Sleeping Sickness
49:30
Ciliate
50:42
Conjugation
53:16
Conjugation
53:26
Animal-Like Protists
57:08
Parabasilids
57:31
Diplomonads
59:06
Rhizopods
1:00:13
Forams
1:02:25
Radiolarians
1:03:28
Fungus-Like Protists
1:04:25
Fungus-Like Protists Overview
1:04:26
Slime Molds
1:05:15
Cellular Slime Molds: Feeding Stage
1:09:21
Oomycetes
1:11:15
Example 1: Alternation of Generations and Sexual Life Cycles
1:13:05
Example 2: Match Protists to Their Descriptions
1:14:12
Example 3: Three Structures that Protists Use for Motility
1:16:22
Example 4: Paramecium
1:17:04
Fungi

35m 24s

Intro
0:00
Introduction to Fungi
0:09
Introduction to Fungi
0:10
Mycologist
0:34
Examples of Fungi
0:45
Hyphae, Mycelia, Chitin, and Coencytic Fungi
2:26
Ancestral Protists
5:00
Role of Fungi in the Environment
5:35
Fungi as Decomposers
5:36
Mycorrrhiza
6:19
Lichen
8:52
Life Cycle of Fungi
11:32
Asexual Reproduction
11:33
Sexual Reproduction & Dikaryotic Cell
13:16
Chytridiomycota
18:12
Phylum Chytridiomycota
18:17
Zoospores
18:50
Zygomycota
19:07
Coenocytic & Zygomycota Life Cycle
19:08
Basidiomycota
24:27
Basidiomycota Overview
24:28
Basidiomycota Life Cycle
26:11
Ascomycota
28:00
Ascomycota Overview
28:01
Ascomycota Reproduction
28:50
Example 1: Fungi Fill in the Blank
31:02
Example 2: Name Two Roles Played by Fungi in the Environment
32:09
Example 3: Difference Between Diploid Cell and Dikaryon Cell
33:42
Example 4: Phylum of Fungi, Flagellated Spore, Coencytic
34:36
Invertebrates

1h 3m 3s

Intro
0:00
Porifera (Sponges)
0:33
Chordata
0:56
Porifera (Sponges): Sessile, Layers, Aceolomates, and Filter Feeders
1:24
Amoebocytes Cell
4:47
Choanocytes Cell
5:56
Sexual Reproduction
6:28
Cnidaria
8:05
Cnidaria Overview
8:06
Polyp & Medusa: Gastrovasular Cavity
8:29
Cnidocytes
9:42
Anthozoa
10:40
Cubozoa
11:23
Hydrozoa
11:53
Scyphoza
13:25
Platyhelminthes (Flatworms)
13:58
Flatworms: Tribloblastic, Bilateral Symmetry, and Cephalization
13:59
GI System
15:33
Excretory System
16:07
Nervous System
17:00
Turbellarians
17:36
Trematodes
18:42
Monageneans
21:32
Cestoda
21:55
Rotifera (Rotifers)
23:45
Rotifers: Digestive Tract, Pseudocoelem, and Stuctures
23:46
Reproduction: Parthenogenesis
25:33
Nematoda (Roundworms)
26:44
Nematoda (Roundworms)
26:45
Parasites: Pinworms & Hookworms
27:26
Annelida
28:36
Annelida Overview
28:37
Open Circulatory
29:21
Closed Circulatory
30:18
Nervous System
31:19
Excretory System
31:43
Oligochaete
32:07
Leeches
33:22
Polychaetes
34:42
Mollusca
35:26
Mollusca Features
35:27
Major Part 1: Visceral Mass
36:21
Major Part 2: Head-foot Region
36:49
Major Part 3: Mantle
37:13
Radula
37:49
Circulatory, Reproductive, Excretory, and Nervous System
38:14
Major Classes of Molluscs
39:12
Gastropoda
39:17
Polyplacophora
40:15
Bivales
40:41
Cephalopods
41:42
Arthropoda
43:35
Arthropoda Overview
43:36
Segmented Bodies
44:14
Exoskeleton
44:52
Jointed Appendages
45:28
Hemolyph, Excretory & Respiratory System
45:41
Myriapoda & Centipedes
47:15
Cheliceriforms
48:20
Crustcea
49:31
Herapoda
50:03
Echinodermata
52:59
Echinodermata
53:00
Watrer Vascular System
54:20
Selected Characteristics of Invertebrates
57:11
Selected Characteristics of Invertebrates
57:12
Example 1: Phylum Description
58:43
Example 2: Complex Animals
59:50
Example 3: Match Organisms to the Correct Phylum
1:01:03
Example 4: Phylum Arthropoda
1:02:01
Vertebrates

1h 7s

Intro
0:00
Phylum Chordata
0:06
Chordates Overview
0:07
Notochord and Dorsal Hollow Nerve Chord
1:24
Pharyngeal Clefts, Arches, and Post-anal Tail
3:41
Invertebrate Chordates
6:48
Lancelets
7:13
Tunicates
8:02
Hagfishes: Craniates
8:55
Vertebrate Chordates
10:41
Veterbrates Overview
10:42
Lampreys
11:00
Gnathostomes
12:20
Six Major Classes of Vertebrates
12:53
chondrichthyes
14:23
Chondrichthyes Overview
14:24
Ectothermic and Endothermic
14:42
Sharks: Lateral Line System, Neuromastsn, and Gills
15:27
Oviparous and Viviparous
17:23
Osteichthyes (Bony Fishes)
18:12
Osteichythes (Bony Fishes) Overview
18:13
Operculum
19:05
Swim Bladder
19:53
Ray-Finned Fishes
20:34
Lobe-Finned Fishes
20:58
Tetrapods
22:36
Tetrapods: Definition and Examples
22:37
Amphibians
23:53
Amphibians Overview
23:54
Order Urodela
25:51
Order Apoda
27:03
Order Anura
27:55
Reptiles
30:19
Reptiles Overview
30:20
Amniotes
30:37
Examples of Reptiles
32:46
Reptiles: Ectotherms, Gas Exchange, and Heart
33:40
Orders of Reptiles
34:17
Sphenodontia, Squamata, Testudines, and Crocodilia
34:21
Birds
36:09
Birds and Dinosaurs
36:18
Theropods
38:00
Birds: High Metabolism, Respiratory System, Lungs, and Heart
39:04
Birds: Endothermic, Bones, and Feathers
40:15
Mammals
42:33
Mammals Overview
42:35
Diaphragm and Heart
42:57
Diphydont
43:44
Synapsids
44:41
Monotremes
46:36
Monotremes
46:37
Marsupials
47:12
Marsupials: Definition and Examples
47:16
Convergent Evolution
48:09
Eutherians (Placental Mammals)
49:42
Placenta
49:43
Order Carnivora
50:48
Order Raodentia
51:00
Order Cetaceans
51:14
Primates
51:41
Primates Overview
51:42
Nails and Hands
51:58
Vision
52:51
Social Care for Young
53:28
Brain
53:43
Example 1: Distinguishing Characteristics of Chordates
54:33
Example 2: Match Description to Correct Term
55:56
Example 3: Bird's Anatomy
57:38
Example 4: Vertebrate Animal, Marine Environment, and Ectothermic
59:14
Section 9: Plants
Seedless Plants

34m 31s

Intro
0:00
Origin and Classification of Plants
0:06
Origin and Classification of Plants
0:07
Non-Vascular vs. Vascular Plants
1:29
Seedless Vascular & Seed Plants
2:28
Angiosperms & Gymnosperms
2:50
Alternation of Generations
3:54
Alternation of Generations
3:55
Bryophytes
7:58
Overview of Bryrophytes
7:59
Example: Moss Gametophyte
9:29
Example: Moss Sporophyte
9:50
Moss Life Cycle
10:12
Moss Life Cycle
10:13
Seedless Vascular Plants
13:23
Vascular Structures: Cell Walls, and Lignin
13:24
Homosporous
17:11
Heterosporous
17:48
Adaptations to Life on land
21:10
Adaptation 1: Cell Walls
21:38
Adaptation 2: Vascular Plants
21:59
Adaptation 3 : Xylem & Phloem
22:31
Adaptation 4: Seeds
23:07
Adaptation 5: Pollen
23:35
Adaptation 6: Stomata
24:45
Adaptation 7: Reduced Gametophyte Generation
25:32
Example 1: Bryophytes
26:39
Example 2: Sporangium, Lignin, Gametophyte, and Antheridium
28:34
Example 3: Adaptations to Life on Land
29:47
Example 4: Life Cycle of Plant
32:06
Plant Structure

1h 1m 21s

Intro
0:00
Plant Tissue
0:05
Dermal Tissue
0:15
Vascular Tissue
0:39
Ground Tissue
1:31
Cell Types in Plants
2:14
Parenchyma Cells
2:24
Collenchyma Cells
3:21
Sclerenchyma Cells
3:59
Xylem
5:04
Xylem: Tracheids and Vessel Elements
6:12
Gymnosperms vs. Angiosperms
7:53
Phloem
8:37
Phloem: Structures and Function
8:38
Sieve-Tube Elements
8:45
Companion Cells & Sieve Plates
9:11
Roots
10:08
Taproots & Fibrous
10:09
Aerial Roots & Prop Roots
11:41
Structures and Functions of Root: Dicot & Monocot
13:00
Pericyle
16:57
The Nitrogen Cylce
18:05
The Nitrogen Cycle
18:06
Mycorrhizae
24:20
Mycorrhizae
24:23
Ectomycorrhiza
26:03
Endomycorrhiza
26:25
Stems
26:53
Stems
26:54
Vascular Bundles of Monocots and Dicots
28:18
Leaves
29:48
Blade & Petiole
30:13
Upper Epidermis, Lower Epidermis & Cuticle
30:39
Ground Tissue, Palisade Mesophyll, Spongy Mesophyll
31:35
Stomata Pores
33:23
Guard Cells
34:15
Vascular Tissues: Vascular Bundles and Bundle Sheath
34:46
Stomata
36:12
Stomata & Gas Exchange
36:16
Guard Cells, Flaccid, and Turgid
36:43
Water Potential
38:03
Factors for Opening Stoma
40:35
Factors Causing Stoma to Close
42:44
Overview of Plant Growth
44:23
Overview of Plant Growth
44:24
Primary Plant Growth
46:19
Apical Meristems
46:25
Root Growth: Zone of Cell Division
46:44
Root Growth: Zone of Cell Elongation
47:35
Root Growth: Zone of Cell Differentiation
47:55
Stem Growth: Leaf Primodia
48:16
Secondary Plant Growth
48:48
Secondary Plant Growth Overview
48:59
Vascular Cambium: Secondary Xylem and Phloem
49:38
Cork Cambium: Periderm and Lenticels
51:10
Example 1: Leaf Structures
53:30
Example 2: List Three Types of Plant Tissue and their Major Functions
55:13
Example 3: What are Two Factors that Stimulate the Opening or Closing of Stomata?
56:58
Example 4: Plant Growth
59:18
Gymnosperms and Angiosperms

1h 1m 51s

Intro
0:00
Seed Plants
0:22
Sporopollenin
0:58
Heterosporous: Megasporangia
2:49
Heterosporous: Microsporangia
3:19
Gymnosperms
5:20
Gymnosperms
5:21
Gymnosperm Life Cycle
7:30
Gymnosperm Life Cycle
7:31
Flower Structure
15:15
Petal & Pollination
15:48
Sepal
16:52
Stamen: Anther, Filament
17:05
Pistill: Stigma, Style, Ovule, Ovary
17:55
Complete Flowers
20:14
Angiosperm Gametophyte Formation
20:47
Male Gametophyte: Microsporocytes, Microsporangia & Meiosis
20:57
Female Gametophyte: Megasporocytes & Meiosis
24:22
Double Fertilization
25:43
Double Fertilization: Pollen Tube and Endosperm
25:44
Angiosperm Life Cycle
29:43
Angiosperm Life Cycle
29:48
Seed Structure and Development
33:37
Seed Structure and Development
33:38
Pollen Dispersal
37:53
Abiotic
38:28
Biotic
39:30
Prevention of Self-Pollination
40:48
Mechanism 1
41:08
Mechanism 2: Dioecious
41:37
Mechanism 3
42:32
Self-Incompatibility
43:08
Gametophytic Self-Incompatibility
44:38
Sporophytic Self-Incompatibility
46:50
Asexual Reproduction
48:33
Asexual Reproduction & Vegetative Propagation
48:34
Graftiry
50:19
Monocots and Dicots
51:34
Monocots vs.Dicots
51:35
Example 1: Double Fertilization
54:43
Example 2: Mechanisms of Self-Fertilization
56:02
Example 3: Monocots vs. Dicots
58:11
Example 4: Flower Structures
1:00:11
Transport of Nutrients and Water in Plants

40m 30s

Intro
0:00
Review of Plant Cell Structure
0:14
Cell Wall, Plasma Membrane, Middle lamella, and Cytoplasm
0:15
Plasmodesmata, Chloroplasts, and Central Vacuole
3:24
Water Absorption by Plants
4:28
Root Hairs and Mycorrhizae
4:30
Osmosis and Water Potential
5:41
Apoplast and Symplast Pathways
10:01
Apoplast and Symplast Pathways
10:02
Xylem Structure
21:02
Tracheids and Vessel Elements
21:03
Bulk Flow
23:00
Transpiration
23:26
Cohesion
25:10
Adhesion
26:10
Phloem Structure
27:25
Pholem
27:26
Sieve-Tube Elements
27:48
Companion Cells
28:17
Translocation
28:42
Sugar Source and Sugar Sink Overview
28:43
Example of Sugar Sink
30:01
Example of Sugar Source
30:48
Example 1: Match the Following Terms to their Description
33:17
Example 2: Water Potential
34:58
Example 3: Bulk Flow
36:56
Example 4: Sugar Sink and Sugar Source
38:33
Plant Hormones and Tropisms

48m 10s

Intro
0:00
Plant Cell Signaling
0:17
Plant Cell Signaling Overview
0:18
Step 1: Reception
1:03
Step 2: Transduction
2:32
Step 3: Response
2:58
Second Messengers
3:52
Protein Kinases
4:42
Auxins
6:14
Auxins
6:18
Indoleacetic Acid (IAA)
7:23
Cytokinins and Gibberellins
11:10
Cytokinins: Apical Dominance & Delay of Aging
11:16
Gibberellins: 'Bolting'
13:51
Ethylene
15:33
Ethylene
15:34
Positive Feedback
15:46
Leaf Abscission
18:05
Mechanical Stress: Triple Response
19:36
Abscisic Acid
21:10
Abscisic Acid
21:15
Tropisms
23:11
Positive Tropism
23:50
Negative Tropism
24:07
Statoliths
26:21
Phytochromes and Photoperiodism
27:48
Phytochromes: PR and PFR
27:56
Circadian Rhythms
32:06
Photoperiod
33:13
Photoperiodism
33:38
Gerner & Allard
34:35
Short-Day Plant
35:22
Long-Day Plant
37:00
Example 1: Plant Hormones
41:28
Example 2: Cytokinins & Gibberellins
43:00
Example 3: Match the Following Terms to their Description
44:46
Example 4: Hormones & Cell Response
46:14
Section 10: Animal Structure and Physiology
The Respiratory System

48m 14s

Intro
0:00
Gas Exchange in Animals
0:17
Respiration
0:19
Ventilation
1:09
Characteristics of Respiratory Surfaces
1:53
Gas Exchange in Aquatic Animals
3:05
Simple Aquatic Animals
3:06
Gills & Gas Exchange in Complex Aquatic Animals
3:49
Countercurrent Exchange
6:12
Gas Exchange in Terrestrial Animals
13:46
Earthworms
14:07
Internal Respiratory
15:35
Insects
16:55
Circulatory Fluid
19:06
The Human Respiratory System
21:21
Nasal Cavity, Pharynx, Larynx, and Epiglottis
21:50
Bronchus, Bronchiole, Trachea, and Alveoli
23:38
Pulmonary Surfactants
28:05
Circulatory System: Hemoglobin
29:13
Ventilation
30:28
Inspiration/Expiration: Diaphragm, Thorax, and Abdomen
30:33
Breathing Control Center: Regulation of pH
34:34
Example 1: Tracheal System in Insects
39:08
Example 2: Countercurrent Exchange
42:09
Example 3: Respiratory System
44:10
Example 4: Diaphragm, Ventilation, pH, and Regulation of Breathing
45:31
The Circulatory System

1h 20m 21s

Intro
0:00
Types of Circulatory Systems
0:07
Circulatory System Overview
0:08
Open Circulatory System
3:19
Closed Circulatory System
5:58
Blood Vessels
7:51
Arteries
8:16
Veins
10:01
Capillaries
12:35
Vasoconstriction and Vasodilation
13:10
Vasoconstriction
13:11
Vasodilation
13:47
Thermoregulation
14:32
Blood
15:53
Plasma
15:54
Cellular Component: Red Blood Cells
17:41
Cellular Component: White Blood Cells
20:18
Platelets
21:14
Blood Types
21:35
Clotting
27:04
Blood, Fibrin, and Clotting
27:05
Hemophilia
30:26
The Heart
31:09
Structures and Functions of the Heart
31:19
Pulmonary and Systemic Circulation
40:20
Double Circuit: Pulmonary Circuit and Systemic Circuit
40:21
The Cardiac Cycle
42:35
The Cardiac Cycle
42:36
Autonomic Nervous System
50:00
Hemoglobin
51:25
Hemoglobin & Hemocyanin
51:26
Oxygen-Hemoglobin Dissociation Curve
55:30
Oxygen-Hemoglobin Dissociation Curve
55:44
Transport of Carbon Dioxide
1:06:31
Transport of Carbon Dioxide
1:06:37
Example 1: Pathway of Blood
1:12:48
Example 2: Oxygenated Blood, Pacemaker, and Clotting
1:15:24
Example 3: Vasodilation and Vasoconstriction
1:16:19
Example 4: Oxygen-Hemoglobin Dissociation Curve
1:18:13
The Digestive System

56m 11s

Intro
0:00
Introduction to Digestion
0:07
Digestive Process
0:08
Intracellular Digestion
0:45
Extracellular Digestion
1:44
Types of Digestive Tracts
2:08
Gastrovascular Cavity
2:09
Complete Gastrointestinal Tract (Alimentary Canal)
3:54
'Crop'
4:43
The Human Digestive System
5:41
Structures of the Human Digestive System
5:47
The Oral Cavity and Esophagus
7:47
Mechanical & Chemical Digestion
7:48
Salivary Glands
8:55
Pharynx and Epigloltis
9:43
Peristalsis
11:35
The Stomach
12:57
Lower Esophageal Sphincter
13:00
Gastric Gland, Parietal Cells, and Pepsin
14:32
Mucus Cell
15:48
Chyme & Pyloric Sphincter
17:32
The Pancreas
18:31
Endocrine and Exocrine
19:03
Amylase
20:05
Proteases
20:51
Lipases
22:20
The Liver
23:08
The Liver & Production of Bile
23:09
The Small Intestine
24:37
The Small Intestine
24:38
Duodenum
27:44
Intestinal Enzymes
28:41
Digestive Enzyme
33:30
Site of Production: Mouth
33:43
Site of Production: Stomach
34:03
Site of Production: Pancreas
34:16
Site of Production: Small Intestine
36:18
Absorption of Nutrients
37:51
Absorption of Nutrients: Jejunum and Ileum
37:52
The Large Intestine
44:52
The Large Intestine: Colon, Cecum, and Rectum
44:53
Regulation of Digestion by Hormones
46:55
Gastrin
47:21
Secretin
47:50
Cholecystokinin (CCK)
48:00
Example 1: Intestinal Cell, Bile, and Digestion of Fats
48:29
Example 2: Matching
51:06
Example 3: Digestion and Absorption of Starch
52:18
Example 4: Large Intestine and Gastric Fluids
54:52
The Excretory System

1h 12m 14s

Intro
0:00
Nitrogenous Wastes
0:08
Nitrogenous Wastes Overview
0:09
NH3
0:39
Urea
2:43
Uric Acid
3:31
Osmoregulation
4:56
Osmoregulation
5:05
Saltwater Fish vs. Freshwater Fish
8:58
Types of Excretory Systems
13:42
Protonephridia
13:50
Metanephridia
16:15
Malpighian Tubule
19:05
The Human Excretory System
20:45
Kidney, Ureter, bladder, Urethra, Medula, and Cortex
20:53
Filtration, Reabsorption and Secretion
22:53
Filtration
22:54
Reabsorption
24:16
Secretion
25:20
The Nephron
26:23
The Nephron
26:24
The Nephron, cont.
41:45
Descending Loop of Henle
41:46
Ascending Loop of Henle
45:45
Antidiuretic Hormone
54:30
Antidiuretic Hormone (ADH)
54:31
Aldosterone
58:58
Aldosterone
58:59
Example 1: Nephron of an Aquatic Mammal
1:04:21
Example 2: Uric Acid & Saltwater Fish
1:06:36
Example 3: Nephron
1:09:14
Example 4: Gastrointestinal Infection
1:10:41
The Endocrine System

51m 12s

Intro
0:00
The Endocrine System Overview
0:07
Thyroid
0:08
Exocrine
1:56
Pancreas
2:44
Paracrine Signaling
4:06
Pheromones
5:15
Mechanisms of Hormone Action
6:06
Reception, Transduction, and Response
7:06
Classes of Hormone
10:05
Negative Feedback: Testosterone Example
12:16
The Pancreas
15:11
The Pancreas & islets of Langerhan
15:12
Insulin
16:02
Glucagon
17:28
The Anterior Pituitary
19:25
Thyroid Stimulating Hormone
20:24
Adrenocorticotropic Hormone
21:16
Follide Stimulating Hormone
22:04
Luteinizing Hormone
22:45
Growth Hormone
23:45
Prolactin
24:24
Melanocyte Stimulating Hormone
24:55
The Hypothalamus and Posterior Pituitary
25:45
Hypothalamus, Oxytocin, Antidiuretic Hormone (ADH), and Posterior Pituitary
25:46
The Adrenal Glands
31:20
Adrenal Cortex
31:56
Adrenal Medulla
34:29
The Thyroid
35:54
Thyroxine
36:09
Calcitonin
40:27
The Parathyroids
41:44
Parathyroids Hormone (PTH)
41:45
The Ovaries and Testes
43:32
Estrogen, Progesterone, and Testosterone
43:33
Example 1: Match the Following Hormones with their Descriptions
45:38
Example 2: Pancreas, Endocrine Organ & Exocrine Organ
47:06
Example 3: Insulin and Glucagon
48:28
Example 4: Increased Level of Cortisol in Blood
50:25
The Nervous System

1h 10m 38s

Intro
0:00
Types of Nervous Systems
0:28
Nerve Net
0:37
Flatworm
1:07
Cephalization
1:52
Arthropods
2:44
Echinoderms
3:11
Nervous System Organization
3:40
Nervous System Organization Overview
3:41
Automatic Nervous System: Sympathetic & Parasympathetic
4:42
Neuron Structure
6:57
Cell Body & Dendrites
7:16
Axon & Axon Hillock
8:20
Synaptic Terminals, Mylenin, and Nodes of Ranvier
9:01
Pre-synaptic and Post-synaptic Cells
10:16
Pre-synaptic Cells
10:17
Post-synaptic Cells
11:05
Types of Neurons
11:50
Sensory Neurons
11:54
Motor Neurons
13:12
Interneurons
14:24
Resting Potential
15:14
Membrane Potential
15:25
Resting Potential: Chemical Gradient
16:06
Resting Potential: Electrical Gradient
19:18
Gated Ion Channels
24:40
Voltage-Gated & Ligand-Gated Ion Channels
24:48
Action Potential
30:09
Action Potential Overview
30:10
Step 1
32:07
Step 2
32:17
Step 3
33:12
Step 4
35:14
Step 5
36:39
Action Potential Transmission
39:04
Action Potential Transmission
39:05
Speed of Conduction
41:19
Saltatory Conduction
42:58
The Synapse
44:17
The Synapse: Presynaptic & Postsynaptic Cell
44:31
Examples of Neurotransmitters
50:05
Brain Structure
51:57
Meniges
52:19
Cerebrum
52:56
Corpus Callosum
53:13
Gray & White Matter
53:38
Cerebral Lobes
55:35
Cerebellum
56:00
Brainstem
56:30
Medulla
56:51
Pons
57:22
Midbrain
57:55
Thalamus
58:25
Hypothalamus
58:58
Ventricles
59:51
The Spinal Cord
1:00:29
Sensory Stimuli
1:00:30
Reflex Arc
1:01:41
Example 1: Automatic Nervous System
1:04:38
Example 2: Synaptic Terminal and the Release of Neurotransmitters
1:06:22
Example 3: Volted-Gated Ion Channels
1:08:00
Example 4: Neuron Structure
1:09:26
Musculoskeletal System

39m 29s

Intro
0:00
Skeletal System Types and Function
0:30
Skeletal System
0:31
Exoskeleton
1:34
Endoskeleton
2:32
Skeletal System Components
2:55
Bone
3:06
Cartilage
5:04
Tendons
6:18
Ligaments
6:34
Skeletal Muscle
6:52
Skeletal Muscle
7:24
Sarcomere
9:50
The Sliding Filament Theory
13:12
The Sliding Filament Theory: Muscle Contraction
13:13
The Neuromuscular Junction
17:24
The Neuromuscular Junction: Motor Neuron & Muscle Fiber
17:26
Sarcolemma, Sarcoplasmic
21:54
Tropomyosin & Troponin
23:35
Summation and Tetanus
25:26
Single Twitch, Summation of Two Twitches, and Tetanus
25:27
Smooth Muscle
28:50
Smooth Muscle
28:58
Cardiac Muscle
30:40
Cardiac Muscle
30:42
Summary of Muscle Types
32:07
Summary of Muscle Types
32:08
Example 1: Contraction and Skeletal Muscle
33:15
Example 2: Skeletal Muscle and Smooth Muscle
36:23
Example 3: Muscle Contraction, Bone, and Nonvascularized Connective Tissue
37:31
Example 4: Sarcomere
38:17
The Immune System

1h 24m 28s

Intro
0:00
The Lymphatic System
0:16
The Lymphatic System Overview
0:17
Function 1
1:23
Function 2
2:27
Barrier Defenses
3:41
Nonspecific vs. Specific Immune Defenses
3:42
Barrier Defenses
5:12
Nonspecific Cellular Defenses
7:50
Nonspecific Cellular Defenses Overview
7:53
Phagocytes
9:29
Neutrophils
11:43
Macrophages
12:15
Natural Killer Cells
12:55
Inflammatory Response
14:19
Complement
18:16
Interferons
18:40
Specific Defenses - Acquired Immunity
20:12
T lymphocytes and B lymphocytes
20:13
B Cells
23:35
B Cells & Humoral Immunity
23:41
Clonal Selection
29:50
Clonal Selection
29:51
Primary Immune Response
34:28
Secondary Immune Response
35:31
Cytotoxic T Cells
38:41
Helper T Cells
39:20
Major Histocompatibility Complex Molecules
40:44
Major Histocompatibility Complex Molecules
40:55
Helper T Cells
52:36
Helper T Cells
52:37
Mechanisms of Antibody Action
59:00
Mechanisms of Antibody Action
59:01
Opsonization
1:00:01
Complement System
1:01:57
Classes of Antibodies
1:02:45
IgM
1:03:01
IgA
1:03:17
IgG
1:03:53
IgE
1:04:10
Passive and Active Immunity
1:05:00
Passive Immunity
1:05:01
Active Immunity
1:07:49
Recognition of Self and Non-Self
1:09:32
Recognition of Self and Non-Self
1:09:33
Self-Tolerance & Autoimmune Diseases
1:10:50
Immunodeficiency
1:13:27
Immunodeficiency
1:13:28
Chemotherapy
1:13:56
AID
1:14:27
Example 1: Match the Following Terms with their Descriptions
1:15:26
Example 2: Three Components of Non-specific Immunity
1:17:59
Example 3: Immunodeficient
1:21:19
Example 4: Self-tolerance and Autoimmune Diseases
1:23:07
Section 11: Animal Reproduction and Development
Reproduction

1h 1m 41s

Intro
0:00
Asexual Reproduction
0:17
Fragmentation
0:53
Fission
1:54
Parthenogenesis
2:38
Sexual Reproduction
4:00
Sexual Reproduction
4:01
Hermaphrodite
8:08
The Male Reproduction System
8:54
Seminiferous Tubules & Leydig Cells
8:55
Epididymis
9:48
Seminal Vesicle
11:19
Bulbourethral
12:37
The Female Reproductive System
13:25
Ovaries
13:28
Fallopian
14:50
Endometrium, Uterus, Cilia, and Cervix
15:03
Mammary Glands
16:44
Spermatogenesis
17:08
Spermatogenesis
17:09
Oogenesis
21:01
Oogenesis
21:02
The Menstrual Cycle
27:56
The Menstrual Cycle: Ovarian and Uterine Cycle
27:57
Summary of the Ovarian and Uterine Cycles
42:54
Ovarian
42:55
Uterine
44:51
Oxytocin and Prolactin
46:33
Oxytocin
46:34
Prolactin
47:00
Regulation of the Male Reproductive System
47:28
Hormones: GnRH, LH, FSH, and Testosterone
47:29
Fertilization
50:11
Fertilization
50:12
Structures of Egg
50:28
Acrosomal Reaction
51:36
Cortical Reaction
53:09
Example 1: List Three Differences between Spermatogenesis and oogenesis
55:36
Example 2: Match the Following Terms to their Descriptions
57:34
Example 3: Pregnancy and the Ovarian Cycle
58:44
Example 4: Hormone
1:00:43
Development

50m 5s

Intro
0:00
Cleavage
0:31
Cleavage
0:32
Meroblastic
2:06
Holoblastic Cleavage
3:23
Protostomes
4:34
Deuterostomes
5:13
Totipotent
5:52
Blastula Formation
6:42
Blastula
6:46
Gastrula Formation
8:12
Deuterostomes
11:02
Protostome
11:44
Ectoderm
12:17
Mesoderm
12:55
Endoderm
13:40
Cytoplasmic Determinants
15:19
Cytoplasmic Determinants
15:23
The Bird Embryo
22:52
Cleavage
23:35
Blastoderm
23:55
Primitive Streak
25:38
Migration and Differentiation
27:09
Extraembryonic Membranes
28:33
Extraembryonic Membranes
28:34
Chorion
30:02
Yolk Sac
30:36
Allantois
31:04
The Mammalian Embryo
32:18
Cleavage
32:28
Blastocyst
32:44
Trophoblast
34:37
Following Implantation
35:48
Organogenesis
37:04
Organogenesis, Notochord and Neural Tube
37:05
Induction
40:15
Induction
40:39
Fate Mapping
41:40
Example 1: Processes and Stages of Embryological Development
42:49
Example 2: Transplanted Cells
44:33
Example 3: Germ Layer
46:41
Example 4: Extraembryonic Membranes
47:28
Section 12: Animal Behavior
Animal Behavior

47m 48s

Intro
0:00
Introduction to Animal Behavior
0:05
Introduction to Animal Behavior
0:06
Ethology
1:04
Proximate Cause & Ultimate Cause
1:46
Fixed Action Pattern
3:07
Sign Stimulus
3:40
Releases and Example
3:55
Exploitation and Example
7:23
Learning
8:56
Habituation, Associative Learning, and Imprinting
8:57
Habituation
10:03
Habituation: Definition and Example
10:04
Associative Learning
11:47
Classical
12:19
Operant Conditioning
13:40
Positive & Negative Reinforcement
14:59
Positive & Negative Punishment
16:13
Extinction
17:28
Imprinting
17:47
Imprinting: Definition and Example
17:48
Social Behavior
20:12
Cooperation
20:38
Agonistic
21:37
Dorminance Heirarchies
23:23
Territoriality
24:08
Altruism
24:55
Communication
26:56
Communication
26:57
Mating
32:38
Mating Overview
32:40
Promiscuous
33:13
Monogamous
33:32
Polygamous
33:48
Intrasexual
34:22
Intersexual Selection
35:08
Foraging
36:08
Optimal Foraging Model
36:39
Foraging
37:47
Movement
39:12
Kinesis
39:20
Taxis
40:17
Migration
40:54
Lunar Cycles
42:02
Lunar Cycles
42:08
Example 1: Types of Conditioning
43:19
Example 2: Match the Following Terms to their Descriptions
44:12
Example 3: How is the Optimal Foraging Model Used to Explain Foraging Behavior
45:47
Example 4: Learning
46:54
Section 13: Ecology
Biomes

58m 49s

Intro
0:00
Ecology
0:08
Ecology
0:14
Environment
0:22
Integrates
1:41
Environment Impacts
2:20
Population and Distribution
3:20
Population
3:21
Range
4:50
Potential Range
5:10
Abiotic
5:46
Biotic
6:22
Climate
7:55
Temperature
8:40
Precipitation
10:00
Wind
10:37
Sunlight
10:54
Macroclimates & Microclimates
11:31
Other Abiotic Factors
12:20
Geography
12:28
Water
13:17
Soil and Rocks
13:48
Sunlight
14:42
Sunlight
14:43
Seasons
15:43
June Solstice, December Solstice, March Equinox, and September Equinox
15:44
Tropics
19:00
Seasonability
19:39
Wind and Weather Patterns
20:44
Vertical Circulation
20:51
Surface Wind Patterns
25:18
Local Climate Effects
26:51
Local Climate Effects
26:52
Terrestrial Biomes
30:04
Biome
30:05
Forest
31:02
Tropical Forest
32:00
Tropical Forest
32:01
Temperate Broadleaf Forest
32:55
Temperate Broadleaf Forest
32:56
Coniferous/Taiga Forest
34:10
Coniferous/Taiga Forest
34:11
Desert
36:05
Desert
36:06
Grassland
37:45
Grassland
37:46
Tundra
40:09
Tundra
40:10
Freshwater Biomes
42:25
Freshwater Biomes: Zones
42:27
Eutrophic Lakes
44:24
Oligotrophic Lakes
45:01
Lakes Turnover
46:03
Rivers
46:51
Wetlands
47:40
Estuary
48:11
Marine Biomes
48:45
Marine Biomes: Zones
48:46
Example 1: Diversity of Life
52:18
Example 2: Marine Biome
53:08
Example 3: Season
54:20
Example 4: Biotic vs. Abiotic
55:54
Population

41m 16s

Intro
0:00
Population
0:07
Size 'N'
0:16
Density
0:41
Dispersion
1:01
Measure Population: Count Individuals, Sampling, and Proxymeasure
2:26
Mortality
7:29
Mortality and Survivorship
7:30
Age Structure Diagrams
11:52
Expanding with Rapid Growth, Expanding, and Stable
11:58
Population Growth
15:39
Biotic Potential & Exponential Growth
15:43
Logistic Population Growth
19:07
Carrying Capacity (K)
19:18
Limiting Factors
20:55
Logistic Model and Oscillation
22:55
Logistic Model and Oscillation
22:56
Changes to the Carrying Capacity
24:36
Changes to the Carrying Capacity
24:37
Growth Strategies
26:07
'r-selected' or 'r-strategist'
26:23
'K-selected' or 'K-strategist'
27:47
Human Population
30:15
Human Population and Exponential Growth
30:21
Case Study - Lynx and Hare
31:54
Case Study - Lynx and Hare
31:55
Example 1: Estimating Population Size
34:35
Example 2: Population Growth
36:45
Example 3: Carrying Capacity
38:17
Example 4: Types of Dispersion
40:15
Communities

1h 6m 26s

Intro
0:00
Community
0:07
Ecosystem
0:40
Interspecific Interactions
1:14
Competition
2:45
Competition Overview
2:46
Competitive Exclusion
3:57
Resource Partitioning
4:45
Character Displacement
6:22
Predation
7:46
Predation
7:47
True Predation
8:05
Grazing/ Herbivory
8:39
Predator Adaptation
10:13
Predator Strategies
10:22
Physical Features
11:02
Prey Adaptation
12:14
Prey Adaptation
12:23
Aposematic Coloration
13:35
Batesian Mimicry
14:32
Size
15:42
Parasitism
16:48
Symbiotic Relationship
16:54
Ectoparasites
18:31
Endoparasites
18:53
Hyperparisitism
19:21
Vector
20:08
Parasitoids
20:54
Mutualism
21:23
Resource - Resource mutualism
21:34
Service - Resource Mutualism
23:31
Service - Service Mutualism: Obligate & Facultative
24:23
Commensalism
26:01
Commensalism
26:03
Symbiosis
27:31
Trophic Structure
28:35
Producers & Consumers: Autotrophs & Heterotrophs
28:36
Food Chain
33:26
Producer & Consumers
33:38
Food Web
39:01
Food Web
39:06
Significant Species within Communities
41:42
Dominant Species
41:50
Keystone Species
42:44
Foundation Species
43:41
Community Dynamics and Disturbances
44:31
Disturbances
44:33
Duration
47:01
Areal Coverage
47:22
Frequency
47:48
Intensity
48:04
Intermediate Level of Disturbance
48:20
Ecological Succession
50:29
Primary and Secondary Ecological Succession
50:30
Example 1: Competition Situation & Outcome
57:18
Example 2: Food Chains
1:00:08
Example 3: Ecological Units
1:02:44
Example 4: Disturbances & Returning to the Original Climax Community
1:04:30
Energy and Ecosystems

57m 42s

Intro
0:00
Ecosystem: Biotic & Abiotic Components
0:15
First Law of Thermodynamics & Energy Flow
0:40
Gross Primary Productivity (GPP)
3:52
Net Primary Productivity (NPP)
4:50
Biogeochemical Cycles
7:16
Law of Conservation of Mass & Biogeochemical Cycles
7:17
Water Cycle
10:55
Water Cycle
10:57
Carbon Cycle
17:52
Carbon Cycle
17:53
Nitrogen Cycle
22:40
Nitrogen Cycle
22:41
Phosphorous Cycle
29:34
Phosphorous Cycle
29:35
Climate Change
33:20
Climate Change
33:21
Eutrophication
39:38
Nitrogen
40:34
Phosphorous
41:29
Eutrophication
42:55
Example 1: Energy and Ecosystems
45:28
Example 2: Atmospheric CO2
48:44
Example 3: Nitrogen Cycle
51:22
Example 4: Conversion of a Forest near a Lake to Farmland
53:20
Section 14: Laboratory Review
Laboratory Review

2h 4m 30s

Intro
0:00
Lab 1: Diffusion and Osmosis
0:09
Lab 1: Diffusion and Osmosis
0:10
Lab 1: Water Potential
11:55
Lab 1: Water Potential
11:56
Lab 2: Enzyme Catalysis
18:30
Lab 2: Enzyme Catalysis
18:31
Lab 3: Mitosis and Meiosis
27:40
Lab 3: Mitosis and Meiosis
27:41
Lab 3: Mitosis and Meiosis
31:50
Ascomycota Life Cycle
31:51
Lab 4: Plant Pigments and Photosynthesis
40:36
Lab 4: Plant Pigments and Photosynthesis
40:37
Lab 5: Cell Respiration
49:56
Lab 5: Cell Respiration
49:57
Lab 6: Molecular Biology
55:06
Lab 6: Molecular Biology & Transformation 1st Part
55:07
Lab 6: Molecular Biology
1:01:16
Lab 6: Molecular Biology 2nd Part
1:01:17
Lab 7: Genetics of Organisms
1:07:32
Lab 7: Genetics of Organisms
1:07:33
Lab 7: Chi-square Analysis
1:13:00
Lab 7: Chi-square Analysis
1:13:03
Lab 8: Population Genetics and Evolution
1:20:41
Lab 8: Population Genetics and Evolution
1:20:42
Lab 9: Transpiration
1:24:02
Lab 9: Transpiration
1:24:03
Lab 10: Physiology of the Circulatory System
1:31:05
Lab 10: Physiology of the Circulatory System
1:31:06
Lab 10: Temperature and Metabolism in Ectotherms
1:38:25
Lab 10: Temperature and Metabolism in Ectotherms
1:38:30
Lab 11: Animal Behavior
1:40:52
Lab 11: Animal Behavior
1:40:53
Lab 12: Dissolved Oxygen & Aquatic Primary Productivity
1:45:36
Lab 12: Dissolved Oxygen & Aquatic Primary Productivity
1:45:37
Lab 12: Primary Productivity
1:49:06
Lab 12: Primary Productivity
1:49:07
Example 1: Chi-square Analysis
1:56:31
Example 2: Mitosis
1:59:28
Example 3: Transpiration of Plants
2:00:27
Example 4: Population Genetic
2:01:16
Section 15: The AP Biology Test
Understanding the Basics

13m 2s

Intro
0:00
AP Biology Structure
0:18
Section I
0:31
Section II
1:16
Scoring
2:04
The Four 'Big Ideas'
3:51
Process of Evolution
4:37
Biological Systems Utilize
4:44
Living Systems
4:55
Biological Systems Interact
5:03
Items to Bring to the Test
7:56
Test Taking Tips
9:53
Section 16: Practice Test (Barron's 4th Edition)
AP Biology Practice Exam: Section I, Part A, Multiple Choice Questions 1-31

1h 4m 29s

Intro
0:00
AP Biology Practice Exam
0:14
Multiple Choice 1
0:40
Multiple Choice 2
2:27
Multiple Choice 3
4:30
Multiple Choice 4
6:43
Multiple Choice 5
9:27
Multiple Choice 6
11:32
Multiple Choice 7
12:54
Multiple Choice 8
14:42
Multiple Choice 9
17:06
Multiple Choice 10
18:42
Multiple Choice 11
20:49
Multiple Choice 12
23:23
Multiple Choice 13
26:20
Multiple Choice 14
27:52
Multiple Choice 15
28:44
Multiple Choice 16
33:07
Multiple Choice 17
35:31
Multiple Choice 18
39:43
Multiple Choice 19
40:37
Multiple Choice 20
42:47
Multiple Choice 21
45:58
Multiple Choice 22
49:49
Multiple Choice 23
53:44
Multiple Choice 24
55:12
Multiple Choice 25
55:59
Multiple Choice 26
56:50
Multiple Choice 27
58:08
Multiple Choice 28
59:54
Multiple Choice 29
1:01:36
Multiple Choice 30
1:02:31
Multiple Choice 31
1:03:50
AP Biology Practice Exam: Section I, Part A, Multiple Choice Questions 32-63

50m 44s

Intro
0:00
AP Biology Practice Exam
0:14
Multiple Choice 32
0:27
Multiple Choice 33
4:14
Multiple Choice 34
5:12
Multiple Choice 35
6:51
Multiple Choice 36
10:46
Multiple Choice 37
11:27
Multiple Choice 38
12:17
Multiple Choice 39
13:49
Multiple Choice 40
17:02
Multiple Choice 41
18:27
Multiple Choice 42
19:35
Multiple Choice 43
21:10
Multiple Choice 44
23:35
Multiple Choice 45
25:00
Multiple Choice 46
26:20
Multiple Choice 47
28:40
Multiple Choice 48
30:14
Multiple Choice 49
31:24
Multiple Choice 50
32:45
Multiple Choice 51
33:41
Multiple Choice 52
34:40
Multiple Choice 53
36:12
Multiple Choice 54
38:06
Multiple Choice 55
38:37
Multiple Choice 56
40:00
Multiple Choice 57
41:18
Multiple Choice 58
43:12
Multiple Choice 59
44:25
Multiple Choice 60
45:02
Multiple Choice 61
46:10
Multiple Choice 62
47:54
Multiple Choice 63
49:01
AP Biology Practice Exam: Section I, Part B, Grid In

21m 52s

Intro
0:00
AP Biology Practice Exam
0:17
Grid In Question 1
0:29
Grid In Question 2
3:49
Grid In Question 3
11:04
Grid In Question 4
13:18
Grid In Question 5
17:01
Grid In Question 6
19:30
AP Biology Practice Exam: Section II, Long Free Response Questions

31m 22s

Intro
0:00
AP Biology Practice Exam
0:18
Free Response 1
0:29
Free Response 2
20:47
AP Biology Practice Exam: Section II, Short Free Response Questions

24m 41s

Intro
0:00
AP Biology Practice Exam
0:15
Free Response 3
0:26
Free Response 4
5:21
Free Response 5
8:25
Free Response 6
11:38
Free Response 7
14:48
Free Response 8
22:14
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Lecture Comments (21)

0 answers

Post by Hammal on October 30, 2021

Hello Professor ! can you give another example of co-dominance ?

2 answers

Last reply by: Andrew Cheesman
Thu Feb 12, 2015 10:44 AM

Post by martin yu on January 19, 2014

The last question about the albino with the punnett square.
Cc x Cc - shouldn't cc = 1/4; why 1/2?

1 answer

Last reply by: Dr Carleen Eaton
Wed Mar 26, 2014 6:34 PM

Post by Muhammad Ziad on January 11, 2014

Hi Dr. Eaton, I am still a little confused on epistasis. Could you clarify it a little bit?

1 answer

Last reply by: Dr Carleen Eaton
Wed Nov 6, 2013 1:18 AM

Post by Maddie G on October 31, 2013

How do alleles differ from variations of genes or single nucleotide polymorphisms?
Particularly in terms of addictions- if a study says they investigated single nucleotide polymorphisms, and that a variant of gene increases vulnerability, how are these two linked? Or are they basically the same thing

0 answers

Post by Omar Younes on October 8, 2013

Hello,

are we not able to fast forward videos?

1 answer

Last reply by: Dr Carleen Eaton
Sun Jan 19, 2014 4:02 PM

Post by bo young lee on March 5, 2013

where can i find more genetic video in your section? (i really like your teaching style then other teacher in educator.com)

1 answer

Last reply by: Dr Carleen Eaton
Wed Jan 9, 2013 2:16 AM

Post by Ramitha Manivannan on December 22, 2012

Dr. Eaton, can I please have your email address so I can ask you questions on this lecture?

1 answer

Last reply by: Dr Carleen Eaton
Fri Dec 9, 2011 12:59 PM

Post by Cameron Saghaiepour on December 8, 2011

I still don't understand law of independent assortment.

1 answer

Last reply by: Dr Carleen Eaton
Fri Dec 9, 2011 12:54 PM

Post by Chris Hahn on December 6, 2011

Example 1:
What is the probability that the child will be tall and have brown eyes?

I thought it was (1/16) x (9/16) = 9/256

0 answers

Post by Sai Nettyam on November 6, 2011

Dr. Easton,

Thank you for the great videos.

0 answers

Post by Billy Jay on April 13, 2011

Little error towards the end. The Test Cross should consist of: CC, Cc, cC, and cc with a 1/4 probability.

1 answer

Last reply by: Ramin Sadat
Thu Sep 5, 2013 7:46 PM

Post by Billy Jay on April 13, 2011

Hi Dr. Eaton,

Do you think the information organized into these series of lectures (on Genetics) are sufficient enough for the Genetics portion of MCAT?

Mendelian Genetics

  • The law of segregation — For any given trait the pair of alleles separate and each gamete receives only one of the alleles.
  • The law of independent assortment — Alleles for a particular trait assort independently of the alleles for other traits.
  • The genotype is the alleles that an individual has for a particular trait. The phenotype is the physical manifestation of the genotype
  • Only one allele is required for the dominant phenotype to be expressed. Two alleles must be present for phenotypic expression of the recessive form of a trait.
  • A Punnett square can be used to predict the genotypes and phenotypes of the offspring from a cross.
  • Incomplete dominance occurs when neither allele is fully dominant over the other. Codominance refers to situations in which both alleles are expressed.
  • With polygenic inheritance, more than one gene controls a trait. Pleiotropy means that a single gene affects multiple traits.
  • Epistasis refers to a gene at one locus affecting the expression of genes at other loci.

Mendelian Genetics

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Background 0:40
    • Gregory Mendel & Mendel's Law
    • Blending Hypothesis
    • Particulate Inheritance
  • Terminology 2:55
    • Gene
    • Locus
    • Allele
    • Dominant Allele
    • Recessive Allele
    • Genotype
    • Phenotype
    • Homozygous
    • Heterozygous
    • Penetrance
    • Expressivity
  • Mendel's Experiments 15:31
    • Mendel's Experiments: Pea Plants
  • The Law of Segregation 21:16
    • Mendel's Conclusions
    • The Law of Segregation
  • Punnett Squares 28:27
    • Using Punnet Squares
  • The Law of Independent Assortment 32:35
    • Monohybrid
    • Dihybrid
    • The Law of Independent Assortment
  • The Law of Independent Assortment, cont. 38:13
    • The Law of Independent Assortment: Punnet Squares
  • Meiosis and Mendel's Laws 43:38
    • Meiosis and Mendel's Laws
  • Test Crosses 49:07
    • Test Crosses Example
  • Probability: Multiplication Rule and the Addition Rule 53:39
    • Probability Overview
    • Independent Events & Multiplication Rule
    • Mutually Exclusive Events & Addition Rule
  • Incomplete Dominance, Codominance and Multiple Alleles 1:02:55
    • Incomplete Dominance
  • Incomplete Dominance, Codominance and Multiple Alleles 1:07:06
    • Codominance and Multiple Alleles
  • Polygenic Inheritance and Pleoitropy 1:10:19
    • Polygenic Inheritance and Pleoitropy
  • Epistasis 1:12:51
    • Example of Epistasis
  • Example 1: Genetic of Eye Color and Height 1:17:39
  • Example 2: Blood Type 1:21:57
  • Example 3: Pea Plants 1:25:09
  • Example 4: Coat Color 1:28:34

Transcription: Mendelian Genetics

Welcome to Educator.com.0000

We are going to start our discussion of heredity with the topic of Mendelian genetics.0002

Let's start out with an exercise. Try to quickly clasp your hands together, and then, look down and see which thumb is on top.0007

Most of you will actually have clasped your hands so that your left thumb is on top. That is actually the dominant trait.0018

Some of you will have your right hand on top. That is the recessive trait.0026

And what we are going to be talking about in today's lesson is going to explain the inheritance of dominant versus recessive traits, and this is just one example.0029

Let's go ahead and get started with Mendelian genetics.0038

To give you some background, Mendelian genetics is named after Gregor Mendel.0044

Mendel was an Austrian monk who performed studies on pea plants in the mid-19th century.0047

And using his observations, he described fundamental principles of inheritance that came to be known as Mendel's laws.0055

Prior to Mendel's discoveries, people believed that the offspring of plants, animals and humans had traits that were a blend of the traits of both their parents.0065

And this was known as the blending hypothesis, so this predated Mendel.0077

For example, if one parent had the blue eyes, and the other had brown eyes, according to the blending hypothesis, the offspring, the children of that couple0086

would have eyes that were a color between the two, maybe light brown or very, very dark blue, so a blend of the two, but it does not always work this way.0099

As you know, the father and mother who both have dark brown eyes can actually have a child with blue eyes.0109

Or parents who the father is very tall and the mother is very short, their kids do not all end up with medium height.0116

So, this theory did not really explain how inheritance worked.0124

Through careful studies of pea plants, Mendel was able to determine that inheritance is through a particulate mechanism, so particulate inheritance.0129

Particulate inheritance describes traits as being passed along via discreet units.0149

Inheritance is through discreet units, and we, now, know the modern term for this is genes.0158

Back in Mendel's time, they did not have the concept of genes, so he called them units; but it is the same idea.0168

Before we go on to Mendel's experiments and Mendelian inheritance, we are going to go through some terminology, just an overview.0175

And then, we are going to go into detail about these concepts throughout the lesson.0182

Starting out with gene, a gene is a section of a chromosome that contains the information about a trait.0186

And in lectures earlier on in the molecular genetics, molecular biology lectures, we talked about DNA, RNA and protein, and we talked about the concept of genes.0194

But just to review, it is a section of a chromosome that contains the information about a trait.0206

And on the molecular level, when we say "contains the information", what we actually mean is the DNA sequence.0226

The DNA sequence - I will put that up here - for a trait.0232

Locus: the locus is the location of a gene on a chromosome.0238

We might say the locus for height. If we have a chromosome, we mean right here.0243

If the gene for height is located right there, we would say this is the locus for height.0252

This is the location of a gene on a chromosome. The plural form is loci- L-O-C-I, this plural.0260

Allele: alleles are alternative forms of a gene.0278

For example, we would say there is a gene for eye color, and two alleles would be a brown allele for brown eyes or blue allele for blue eyes.0289

We could say there is a gene for height. Example: the gene for eye color has two alleles- blue and brown.0300

The gene for height that determines height, there could be a tall allele. There could be a short allele.0314

When we talk about just simple Mendelian inheritance, there are only two alleles per trait.0325

What we are going to be talking about today with pea plants, there will be a tall allele, a short allele, for flower color, purple allele, white allele.0330

In reality, it is often more complex.0339

But a lot of the problems you will see in the AP test, and the problems we will work on today, we will just assume that there is two alleles per trait.0341

The dominant allele: if an allele is dominant, only one allele is needed for the genotype to be expressed, so one allele needed for expression.0348

What I mean by that is recall that humans and many, many organisms are diploid, so if an organism is diploid,0365

they are going to have two copies of each chromosome- one maternally derived, one paternally derived.0376

Let's say that we have a cell, and there is, for human, 46 chromosomes, 23 sets, and on chromosome 1, there is the allele for eye color.0386

And there would be a chromosome 1 from your father and a chromosome 1 from your mother.0399

Maybe your father gave you the blue-eyed gene, the blue-eyed allele for the eye gene, the trait eye color.0403

And maybe from your mother you got the brown-eyed allele.0415

Well, only one allele is needed for expression of the dominant trait, so it turns out that brown eyes are dominant.0421

So, if you have one blue eye allele and one brown eye allele, your eyes would be brown according to the type of expression.0428

The terminology or the symbolism used in Mendelian genetics for a dominant allele is a capital letter.0443

If we are talking about eye color, brown eyes would be big B. That is the dominant allele.0452

The recessive allele, two alleles are needed for expression of that form of the trait.0459

An example would be blue eyes. Little b is blue.0470

So, this individual has a big B, brown and a little b, blue. This individual has brown eyes.0475

There may be another individual who has received from both their mother and father blue-eyed allele- blue from mom and blue from dad.0484

This individual would have little b-little b and, therefore, blue eyes.0496

You can think of it as the brown takes over. It covers up the blue allele, so therefore, it is dominant.0501

Just another example is height.0510

If tall is dominant, then, we would say that the tall allele is big T, and if short is recessive, then, we would have a little t and say that is short.0513

An individual who is big T-big T would be tall. An individual who is little t-little t would be short.0524

And an individual who is one big T-one little t would be tall because when there is a dominant allele, it does not matter what the second allele is.0533

Any individual with the big T, no matter what the second allele is, will be tall.0543

An individual with a big B, no matter what the second allele is, will be brown-eyed according to Mendelian genetics.0547

And again, we are going to go through all of this step by step, but just to give you a vocabulary to be able to understand what we are going over.0555

Genotype: I already mentioned the word genotype, but formally, that is the alleles an individual has for a trait.0563

This person has the genotype big B-little b, brown-eyed allele and a blue-eyed allele.0579

This individual has the genotype little b-little b. Here, we might have an individual big T-big T.0588

So, it is the alleles that they inherited, brown and blue; blue and blue; tall and tall.0596

Phenotype is the physical manifestation of the genotype, so it is the physical manifestation of the genotype.0602

Here, the genotype is big B-big B, so example would be big B-big B. I would say that is the genotype; the phenotype- brown eyes.0619

Here, the genotype is little b-little b; phenotype- blue eyes.0634

Here, genotype- big T-big T; phenotype- tall height.0639

Homozygous means that both alleles are the same.0646

If an individual is homozygous dominant, they would have two dominant alleles.0664

This individual is homozygous dominant, so example would be big T-big T- homozygous dominant.0670

If an individual is, say, little t-little t, they have both alleles for short height,0681

then, we say that individual is homozygous recessive concerning their genotypes.0687

So, the genotype here is homozygous recessive. The genotype here is homozygous dominant.0694

Heterozygous means the alleles are different.0700

This individual has an allele for brown eyes and the allele for blue eyes, so they are heterozygous for the trait of eye color.0706

Penetrance refers to the proportion of people with the particular allele who express the phenotype,0719

so proportion of individuals with an allele who express the phenotype. Now, what does this mean?0728

Well, when we talk later today about Mendelian inheritance,0747

we are going to assume full penetrance meaning if an individual gets an allele for brown eyes, she will have brown eyes.0751

If an individual is heterozygous for height, big T-little t, we expect an individual to be tall. He will be tall, so that is full penetrance.0761

A lot of times when we talk about penetrance, we are talking about diseases, so let's talk about disorders that have a genetic basis as an example.0773

One example is a mutation that can occur in - or mutations - in the BRCA1 and BRCA2 genes.0784

Mutations in these genes have been associated with a greatly increased risk of developing breast cancer. However, there is not complete penetrance.0794

Complete penetrance means if somebody has the allele, they show the phenotype.0803

Complete penetrance with eye color would mean 100% of the time that somebody has the brown genotype,0809

big B-little b or big B-big B, they have brown eyes. That is complete penetrance.0817

Looking at mutations in these genes, if somebody gets the mutated allele of BRCA1 and BRCA2,0823

they have an increased chance of breast cancer, but it is not 100%.0830

Let's say that it is 80%. Let's say they have an 80% chance of developing breast cancer.0833

That means that the penetrance is 80%.0839

Complete penetrance is 100%. That means an individual has the allele.0843

They will express the trait. When we talk about Mendelian genetics, we are going to assume full penetrance.0849

Expressivity is a little bit different. This refers to the range of symptoms a person could have for a disease.0856

If penetrance means they have the disease, they do not have the disease or the trait, but within that, there could be variable expression of it.0866

You could have influenza. You could have the flu.0875

You might have just a little bit of coughing and a low-grade fever.0879

Somebody else gets the flu. They might be very, very ill, have respiratory distress, very high fever, get extremely sick.0883

Those are not genetic disorders, but just to give you an example of range of symptoms.0894

When we are talking about a genetic disorder, same idea with the range of symptoms, so a range of symptoms.0899

Let's say the penetrance was 70% if somebody gets an allele for disease, and the 70% of individuals with the allele get the disease.0910

But within that, there is variable level of expression.0921

Some of those individuals, lot of symptoms. Some only have a few symptoms.0925

With the terminology down, we are going to go on and talk about the experiments that Mendel performed.0933

And Mendel used pea plants as a method of studying inheritance.0937

And pea plants were an excellent organism to use, and the reason is, they had advantages such as the ability to both self-pollinate and to cross-pollinate.0942

They had traits that are easily distinguishable. You could just look and see, there is flower color that is different or the height or the seeds.0956

They also produced a large number of offspring. To have a statistically significant result, you need a lot of offspring to tally up.0964

I will list the traits that he looked at. You do not have to memorize all these, and we are just going to focus on a couple of them.0976

But just so you know, he studied the length of the stem, which gives the height; pod shape; seed shape;0981

seed color; the position of the flower; the color of the flower; and the color of the pods.0988

These are the traits that he studied, and each of these traits came in two forms.0993

Looking first here at height, height in pea plants, they could be either tall or short.0999

And we are going to have, just as I mentioned, big T is going to be the allele for tall, and little t is going to be the allele for short.1006

And at this point, of course, when he started out, Mendel did not know about alleles and all that.1016

So, what he started out doing first is establishing that the plants he started out with were true breeding.1021

And by true breeding, that means that when he self-pollinated a tall plant, all of the offspring were tall.1029

When he self-pollinated a short plant, all of the offspring were short- over and over and over.1038

If he took one tall plant, that when it was self-pollinated, always a tall offspring, and he took a tall plant like that and crossed it.1043

By crossing, we mean he mated it with another tall plant. All of those offspring were tall, so they were true breeding for a trait.1052

The offspring had that trait as long as they were bred with another true breeding tall plant1059

or the short with the short or crossed with another true breeding plant.1065

Looking at some more terminology when we talk about these crosses or these matings, you will see this frequently used.1074

So, this capital P stands for the parental generation.1083

The next generation is F1, the offspring from the parental generation, and this F means filial, so F1 and then, F2, so filial 1, filial 2.1094

Once Mendel had determined that he had true breeding tall plants and true breeding short plants, then, he went ahead, and he crossed them.1109

He mated them, and he was able to do this cross-pollination by cutting this stamen.1120

The stamen is the male reproductive part in the plant. It produces the pollen, so it is the male reproductive organ on the plant.1126

And he cut those off before they were mature so that the plant could not self-pollinate.1139

He, then, took that pollen from the stamen and dusted it on the carpal. The carpal is the female reproductive organ in a plant.1143

He did these cross-pollinations with a tall plant and a short plant.1153

And he did many of these, and what he found was that all of the offspring turned out to be tall.1159

So, here, we have a tall plant, and then, here, we have a short cross in the parental generation- the F1 generation, all tall.1167

According to the blending hypothesis, what you would have expected crossing a tall and short plant is a bunch of medium height plants.1180

That did not happen, and for now, the short trait seemed to be gone.1188

This finding right here, first of all, did support the particular model that it is not just blend between the two.1194

But he went further and really showed what happened.1204

What Mendel, then, did was self-pollinated these F1 plants and then, looked at their offspring.1207

And what happened is the short height reappeared. The short phenotype reappeared.1216

And he found that there was a 3:1 ratio of tall to short, so it was 3:1 ratio of tall to short.1222

The allele or the form of the trait for height that is the short trait stayed intact.1242

It did not blend together with the tall and get changed in some way. It stayed intact, but it just remained hidden for one generation.1251

And now, we are going to talk a little bit about the observations he made and the laws that he derived from this,1258

and talk about how chromosomes and what we know about organisms being diploid can account for these findings.1268

Mendel made some observations and some conclusions, and then, based on the conclusions, we get Mendel's laws; and one of them is the law of segregation.1279

Before we go into that, let's look at Mendel's conclusions. One of his conclusions was that inheritance of each trait is determined by units.1287

Again, we call these units genes now. That is what we realized that they are and that genes are located on chromosomes.1314

The second conclusion that he drew is that an individual inherits one unit from each parent.1325

And you know this already from the molecular biology that we are diploid and that we inherit one of each type of chromosome from each parent.1341

The third conclusion that Mendel drew is that a trait may not show up in an individual, but it can still be passed on to the next generation.1352

So, just abbreviating that as a trait may skip a generation.1367

Let's look at what is happening. The parental plants were true breeding.1378

If they were true breeding, it turns out that all the alleles that they carry, the only alleles that they had for the tall plants, the tall allele.1385

So, they were homozygous dominant. They were homozygous dominant.1395

The short plants carried only the short alleles, the short height alleles, so they were homozygous recessive.1406

And what the law of segregation is telling us is that for any given trait, the pair of alleles will separate, and each gamete receives only one of the alleles.1420

In the P generation, we have got a tall parent who is diploid, and we have the short parent who is also diploid. They form gametes.1428

Let's say that this is the mother. This is the father.1438

Then, gametes are going to form for the female parent, and during meiosis, homologous chromosomes separate.1442

The egg is going to end up with just one of each chromosomes, so here, we are going to end up with gametes carrying just one big T.1457

That is the only choice because there is no other type of allele in there.1466

Here, the alleles also separate to form male gametes, and each of those will carry a little T.1470

Now, when these are crossed, fertilization occurs. Pollination occurs, and the gametes will join to form a zygote, and that is in the F1 generation.1481

The female parent is going to donate a gamete containing a big T. The male parent is going to donate a gamete containing a little t.1498

And so here, we have the F1 generation, and they are all heterozygous.1507

There is no other choice. There is no other combination because they are going to get one allele from each parent, so they are heterozygous.1518

Because tall is dominant, the heterozygotes are going to be tall because a dominant trait only requires one allele for phenotypic expression.1528

In order to get expression of the recessive trait, there needs to be two alleles. There needs to be two alleles.1539

The only way you are going to get short height is if the individual is homozygous recessive.1545

Now, how did short height reappear?1551

Well, in the F1 generation, once again, gametes are formed.1554

And this time, the pair of alleles separate as usual, and gametes form one allele in each gamete.1561

Some gametes get the big T. Some gametes get the little t.1570

You have all these gametes, and now, self-pollination occurs, and you could get a variety of combinations.1577

The big T from the mother could pair up with the little t. It is self-pollination, so it is the same plant, but still, there would be male and female gametes.1591

Big T with the little t- that is one possibility for the F2 generation.1603

The mother might donate a big T. The father might donate a little t.1609

The mother might donate a big T, and the father donates a big T.1616

The other possibility is that the mother donates the big T. Father donates the little t, or the mother donates the little t; and the father donates the little t.1626

These gametes can mix and match, and we are going to lay this all out in a couple minutes in a Punnett square.1637

But the idea is that the gametes, some are carrying big T. Some are carrying little t from the mother.1643

The male gametes, some are carrying big T. Some are carrying little t, and these can mix all different ways to give you four possibilities.1649

Big T-little t, the heterozygote, that plant will be tall. Big T-Big T, homozygous dominant, that plant will be tall.1660

Big T-little t, that is just another heterozygote I wrote it the opposite way. We usually write it this way, but I was trying to show each match, again, tall.1668

Little t-little t, homozygous recessive, that plant will be short, and here is where we get the 3:1 phenotypic ratio of tall to short.1678

The genotypic ratio is actually 1:2:1, one homozygous dominant to two heterozygotes to one homozygous recessive.1689

And the easiest way to understand this F1 cross is by organizing information as a Punnett square.1704

Punnett squares are a way of diagraming out information into a table and allowing you to analyze it and predict the outcome of a particular cross.1711

Let's start with our parental generation.1720

In the parental cross, we had true breeding tall plants and true breeding short plants.1725

And in a Punnett square, what you are going to do at the top is put the gametes from one parent, so let's say that this is the female, and this is the male.1733

It does not matter, but let's just say. One parent will create gametes, and her gametes are all going to be...she is going to give T or T.1743

That is the only choices, so the gametes are going to be right here.1757

Then, we have the male parent. His gametes are all going to carry little t alleles, so little t-little t.1763

So, we have two parents. We showed the possibilities for the alleles that will be carried in their gametes, and now, we do the cross.1769

The father could donate a big T, and the mother or excuse me, the father could donate a little t, the mother, a big T.1777

And we usually write the dominant allele first.1785

Here, the second box, we are going to cross the little t and big T. We are going to combine to show what the offspring could be genotypically.1788

Next, little t-big T, next, little t again, big T again.1800

So, this shows the result that you are going to see in the F1 generation and why they are all heterozygotes.1809

Now, let's go on and look at when we take these F1 parents and either self-pollinate or cross-pollinate, what would we get?1816

Well, we are going to have one parent who is big T-little t heterozygote, and the other parent is big T-little t heterozygote.1829

We are going to put one parent up here just to be consistent.1836

This parent when it forms gametes, and the alleles will segregate, and in some gametes, half the gametes will have a big T. Half will have a little t.1842

Same for this parent, it forms gametes.1852

Half the gametes will have bit T. Half will have little t.1854

The cross is performed.1858

The chromosomes come together, and diploidy is restored in the offspring.1861

And we end up with, in this offspring, a big T from one parent, a big T from the other.1869

This cross, a big T from dad, little t from mom. Here, little t from dad, big T from mom, and here, little t and also a little t from mom.1875

Here, we get our 3:1 ratio. This plant will be tall.1888

This plant will be tall. This plant will be tall.1894

The homozygous recessive plant will be short, and we get 3:1 1, 2, 3 tall plants to one short plant.1898

The genotypic ratio is going to be one big T for every big T-big T homozygous dominant,1907

for every two heterozygotes and then, to every one homozygous recessive.1916

Punnett square can be very useful in organizing information about a cross and predicting offspring1926

at what the genotypes and phenotypes of the offspring will be, so this is the F2 offspring.1932

This first law that we talked about, Mendel's law, was the law of segregation,1941

the idea that the alleles segregate during gamete formation, and each gamete receives one allele.1946

The second law is the law of independent assortment.1955

The cross we talked about before, we looked at only one trait. We looked at height.1959

And when you cross individuals who are heterozygous, they differ by one trait, and they are heterozygous for that trait.1964

That is what you are studying. That is called the monohybrid cross.1971

The first cross that we looked at with the height was monohybrid.1974

You cross individuals who are heterozygous for one trait.1979

We did a monohybrid cross that was studying height.1994

And in the F1 generation, that was a monohybrid cross because in the F1 generation, we were crossing big T-little t with big T-little t.1997

Another of Mendel's very important laws is the law of independent assortment, and to determine this, it required a dihybrid cross.2012

In a dihybrid cross, so when we say hybrid, we are talking about heterozygotes and di is two.2019

We crossed individuals who are heterozygous, so we crossed heterozygotes for two traits, so individuals who are heterozygous for two traits.2026

What the law of independent assortment says is that alleles for a particular trait assort independently of alleles for other traits.2043

So, here, Mendel was studying tall versus short, so the two traits here are height.2051

And the second trait is flower color- height, tall or short and flower color.2058

And for flower color, purple is dominant. Big P is purple.2068

It is dominant. Little p is white, and it is recessive.2073

And from these crosses, what it turned out is that the assortment of alleles for height is not affected by the assortment of the alleles for flower color.2083

Those two separate out and mix and match independently, so let's look at what happened in this cross.2097

First, Mendel had to determine that to determine that he had true breeding plants.2103

So, he started out with plants that are true breeding for height and flower color.2106

One plant here is true breeding for tall height, so it is big T-big T.2112

It is also true breeding for purple flower color, so it is big P-big P.2116

The second plant is true breeding for short height, little t-little t and for white flower color, so little p-little p.2122

He crossed these plants and what he came up with is a bunch of plants that were tall with purple flowers.2134

And this is not surprising because if we look at what gametes are going to form, the gametes that are the only possibility is a gamete for big T, big P,2145

homozygous dominant and homozygous recessive because each gamete has to get an allele for height and an allele for flower color.2158

And they are all going to get tall and purple. These gametes are all going to get short and white.2165

So, the result is a bunch of heterozygotes who all are carrying a big T from one parent,2172

a little t from the other, a big P from one parent, a little p from the other.2178

All the plants are heterozygotes, and they are tall with purple flowers.2183

And here is the dihybrid cross self-pollinating the F1 plants so that you are crossing2191

heterozygotes for two traits, big T-little t, big P-little p, little t-little t, big T again.2196

This is parental. This is F1, OK, crossing these heterozygotes.2206

And what happened is Mendel found that he got in the F2 generation some plants that were tall and purple, others that were short with purple flowers.2214

And then, he also got tall with white flowers, short with white flowers.2231

So, we see all different mixes represented, and we are going to talk in a second about why this occurs.2236

But for right now, just know that it was a 9:3:3:1 phenotypic ratio.2244

The 9 is the dominant-dominant, so tall-purple, so both dominant traits, phenotypes, then, 3 and 3 with one dominant trait and one recessive trait.2255

Here, we have height was recessive. Flower color, we got the dominant purple.2274

Here, we have the dominant height but the recessive flower color, and here, recessive for both, so phenotypic ratio 9:3:3:1.2281

What happened? Well, again, we are going to look at Punnett squares and talk about how alleles assort independently.2293

Allele for one trait does not affect where the allele for another trait goes.2302

Let's look at our Punnett square. Let's look at the F1 generation.2311

In the F1 generation, we have big T-little t, big P-little p being crossed with big T-little T, big P-little p.2316

When gametes form, let's look at this parent first, gametes are going to form.2327

One gamete could have a big T and a big P in it, so that is one possibility; or a gamete could have a big T and a little p.2333

A gamete could have a big T with a big P. A gamete could have a little t with a little p.2351

So, you see, this is not just sticking big T with big P. They are mixing and matching.2361

That is one parent. Now, let's look at this second parent and put the gametes over on this side.2372

Again, we could have big T and big P end up in a gamete dominant-dominant.2377

We could have little t with big P. We could have big T, actually, let me start that over, stay consistent, big T with big P.2383

We could have big T with little p, little t-big P, little t-little p.2399

Then, we do our crosses, big T-big T, big P-big P, big T for both, big P, and this one has a little p.2408

Here, we have a gamete with big T and little t, both homozygous dominant for flower color.2421

Here, we have tall with short allele purple flower with white allele.2429

And I am just going to go ahead and write the rest of these in, but definitely try this on your own.2435

Here, we have big T with a little t and then, homozygous dominant for flower color.2454

And then, make sure you double check your work and not go too fast on this.2461

Here, we have homozygous recessive for height and homozygous recessive for height,2466

heterozygous for flower color, big T-little t and then, homozygous for flower color.2477

OK, let's look at what we have.2491

Mendel observed 9:3:3:1. He saw 9 tall purple that says dominant, two 3 tall with white flower, one dominant trait, one recessive phenotype.2494

And then, there were 3 purple short again, one recessive trait, one dominant, and then, the 1 with both recessive phenotypes 9:3:3:1.2514

That would be a plant that is short with white flowers, and let's see what we did get: tall purple.2531

Let's have this be blue, so there is one tall purple, two tall purples, three tall purples2539

because heterozygotes are going to have the dominant phenotype, 4, 5, 6, 7, 8 that is short-short, 9 right here, so 9 tall purples.2546

Now, how about tall-white? Tall-white, that is one.2564

Tall-white, that is two, short-short, tall-white, that is three, then, short-purple.2571

So, we have short and purple one, short and purple two, short and purple three, and finally, short and white with this circle that is only one of those.2583

OK, the genotypic ratio is complicated, but you cannot look through it the Punnett square and figure that out, as well.2595

And this Punnett square demonstrates this 9:3:3:1 ratio from an F1 dihybrid cross that we did.2610

Now, let's look at how the events in meiosis can account for the findings that Mendel had when he bred pea plants.2618

Looking at this on a chromosome level, on a molecular level, the laws of segregation and independent assortment, so let's review meiosis.2627

Here, we have an individual, and let's say that this is a human, and they have their usual 46 chromosomes, 23 pairs.2638

And let's say that the purple chromosome, the large chromosomes are chromosome 1.2648

This individual is diploid, so they have one chromosome 1 from their mother.2654

And we are going to say that purple is the chromosome that is maternally derived.2659

This individual inherited the purple chromosomes from his mother.2666

And he inherited the green chromosomes from his father- maternally derived and paternally derived are inherited.2670

They get a chromosome 1 from each parent, and they received a chromosome 2 from each parent-2683

chromosome 1 and 2 from mom, a chromosome 1 and 2 from dad.2692

Now, let's say that on chromosome 1, let's just say that eye color is on chromosome 1, and let's say that height is on chromosome 2.2695

Maybe this individual received a brown-eyed allele from his mother and a blue-eyed allele from his father.2714

And let's say he received a tall allele from the mother and a short allele from the father2722

because we are saying that eye color is in chromosome 1 and height is in chromosome 2.2728

Now, let's first look at the idea of segregation.2732

According to Mendel's law of segregation, the gametes right here, and if this individual is a male, these are going to be sperm.2736

During spermatogenesis, the formation of sperm, recall that homologous chromosomes will line up on the metaphase plate.2745

And they will separate to opposite poles of the cell.2753

An individual will receive only one chromosome 1 in each cell, and then, one chromosome 2 in each cell.2756

Here is chromosome 1, one over here, chromosome 1, one, one over there, and then, the sister chromatids separate as you will recall.2775

Chromosome 2, they received one here and one there.2784

This is the law of segregation, whereby the alleles separate during gamete formation, and then, gametes each only get one allele.2787

The second law is the law of independent assortment.2804

Now, in independent assortment, it says that alleles from one trait assort or separate out independently from the alleles of another trait.2807

What that means is that the alleles for eye color are not going to affect the assortment of the alleles for height.2821

Even though brown eye color came from the mom, and tall came from the mom, it does not matter.2835

Brown could end up with short. Brown does not have to stay with tall.2844

These two do not stay together. They assort independently.2855

It might so happen that the maternally derived chromosome goes into one cell for chromosome 1.2859

And the paternally derived chromosome 2 goes into that cell.2867

Or it could have so happened that these two did stay together, and then, the gamete could have been tall with brown eyes alleles.2870

The alleles segregate independently because they are in different chromosome.2884

Now, we are going to talk in the next lecture about linkage, what happens if two traits are on the same chromosome.2888

If it just so happened that eye color and height were both on chromosome 1, then, they are going to stay together more often.2895

But for simple Mendelian genetics, we assume that traits are on different chromosomes. They assort independently.2904

And what happens with an eye color allele has nothing to do with what happens to a height allele or allele for flower color or allele for another trait.2911

You can see here the genetic, the chromosomal basis of Mendelian inheritance that each gamete does get one allele for each trait because of segregation,2920

and that the assortment of the alleles for different traits is independent of one another.2938

Alright, we are going to talk about another kind of cross called the test cross.2948

A test cross is sometimes also called a backcross.2953

It can be used to determine the genotype of an individual who exhibits the dominant phenotype for a trait.2955

Again, we are going to talk about height.2962

If a plant is short, that is the phenotype. I know the genotype.2964

It has got to be homozygous recessive because the only way you are going to get a short individual is if they have two alleles for short height.2971

Dominant traits are different. Tall, all you need is one allele to get a tall plant.2979

So, I could look at a plant, see that is tall, and I do not know what its genotype is. I know it is big T something else.2987

But the question is, is it big T-big T, homozygous dominant, or is it big T-little t, homozygous recessive, heterozygous, heterozygous?2993

I can determine the genotype of this individual by crossing it with an individual who has the recessive phenotype.3010

So, a test cross is crossing the unknown individual with a dominant phenotype.3020

And then, I am going to cross that individual with an individual who has the recessive phenotype, again, illustrating it with this example.3033

I have tall question mark. For my test cross, I am going to take that plant, and I am going to cross it with another plant that is short- tall, short.3046

And then, I am going to look at the offspring and see what the offspring are, and that will tell me what this plant's genotype is; so there is two possibilities.3067

The first possibility is it could turn out...so, I know that this plant, this parent is little t-little t, and I know that this parent is big T.3077

Now, what if the second allele is also tall? What am I going to end up getting for these offspring?3086

Well, I am going to get big T-little t here, big T-little t here. Down here, I am going to get big T-big T, little t-little t.3102

If this plant is homozygous dominant, this offspring is tall. This offspring is tall.3116

This offspring is tall, and this offspring is tall; and I have to get enough offspring for this to be statistically significant.3123

So, if I get many, many offspring, and I see they are all tall, I know that this parent plant is actually homozygous dominant.3132

Now, let's say that this plant turns out to be heterozygous. Then, what I will all have is this parent little t-little t, this parent big T-little t right here.3142

Actually, let's make that blue.3163

Big T-little t, big T-little t, here, we have in blue, little t.3170

So, this is if the parent is actually heterozygous, or the unknown genotype plant is heterozygous.3182

What I am going to have here is tall, tall, short, short.3187

If I see that half the plants are tall and half are short, I know that the genotype was big T-little t.3193

If they are all tall, the offspring, then, I know it was homozygous dominant, the unknown genotype.3203

So, this is a test cross, and it is used to determine the genotype for an individual with the dominant phenotype.3210

OK, we have talked about Punnett squares, and we have been using probabilities.3221

And now, we are going to cover some of the laws of probability more formally.3224

You can use a Punnett square, but there are times when it is much faster and simpler to just go straight for the math to do the probabilities.3228

The probability that an event will occur ranges between 0 and 1.3238

0: there is no chance that an event will occur. With 1 there is 100% chance.3243

If you are looking at probability, then, the probabilities of all the possible outcomes need to add up to 1.3266

Probability of all outcomes must add up to 1.3279

For example, if I am rolling a die, the chances that I will roll one are 1 out of 6. The chances that I am going to roll a two are 1 out of 6.3290

The chances I will roll a three, 1 out 6, four, then, I will roll a five; and then, I will roll a six.3303

Now, when I roll the dice, I have to roll one of these numbers. There is 100% chance I will roll one of these numbers.3311

So, the chance that I will roll a one, a two, a three, a four, a five and a six, when I add that up, that equals 1.3317

Thus, I am going to roll one of these, so that is the first thing.3323

Probability, 0 has no chance. A probability of even bet occurring can be all the way up to one.3327

If every side of the dice had a one on it or a four on it, my chances of rolling a four would be 1. It would be 100%.3333

For independent events, the outcome of one event does not affect subsequent outcomes.3343

So, if I roll a two, and then, I roll the dice again...3356

OK, so if I roll the dice and I get a two, and then, I roll it again, and I say 'hmm, what are the chances I am going to get a two?". It is still 1/6.3362

If I roll the dice again, I have gotten 2 twos, what are the chances I am getting a two again? 1/6.3373

Now, let's say, though, before I roll the dice at all, I want to know what are the chances I am going to get 2 or 3 twos.3380

That is where the multiplication rule comes in. The multiplication rule will give you the probability of two independent events occurring.3390

The probability of two independent events occurring is equal to the product of the probabilities of each event occurring.3423

So, the probability of two independent events occurring is equal to the product of the probabilities of each of those events occurring.3448

What does that mean?3454

Let's say that I have two balls, and one is red. One is blue, and I put the balls in a bag; and I cannot see what is in there, and I pull out a ball.3455

And then, I look at what color it is. I throw it back in.3468

I, kind of, shake it up again. I pull out another ball.3470

Those are independent events.3474

What I pulled out the first time has no effect what I pick the second time, and I ask, what is the probability of choosing red two times?3475

If I grab a ball, look at it, throw it back, grab another ball, what are the probability that I am going to choose red twice?3493

Well, the probability that I will choose red the first time is 1/2, 1 out of 2.3499

When I grab a ball, there is red one in there. There is blue one in there.3507

The chances that I am going to get a red ball are, it is 1 out of 2, so that is first time.3512

The second time, same thing. There is still a red ball in there and a blue ball.3519

The chances of choosing the red one, the probability is 1/2.3522

So, the probability of choosing a red ball the first time is 1/2 times the probability of choosing a ball that is red the second time is 1/2.3529

The probability of choosing red both times is 1/4.3538

So, the probability of two events occurring that are independent, this and this occurring, when I hear "and", I am going to multiply.3542

The addition rule has to do with mutually exclusive events, so that is slightly different.3550

Now, before we go on to that, just to quickly apply this probability rule, this multiplication rule, to genetics.3558

Let's say I am doing a monohybrid cross, and I have height, big T-little t. It is heterozygous, and I do the cross.3568

What are the chances that the offspring will be homozygous dominant?3577

Well, in order for it to be homozygous dominant, this parent needs to donate a big T.3585

The chances of that, the probability is 1/2, and so I multiply.3591

What are the chances, the probability, that the second parent will donate a big T? 1/2.3596

Therefore, the probability of the offspring being a homozygous dominant is 1/4.3603

Sometimes, you will be asked to use decimals.3610

It is the same thing. You can convert after, or you can just say "OK, 0.5 x 0.5 is a 0.25", so sometimes, it is easier to work with decimals.3613

Now, the addition rule, the multiplication rule here had to do with independent events. The addition rule has to do with mutually exclusive events.3627

When you are talking about mutually exclusive events, you are talking about a situation where both events cannot occur at the same time.3639

Mutually exclusive, so both events cannot occur.3647

Let's say that I am rolling a die one time, and I want to know the probability that I will roll a one or a six on that single roll.3653

I cannot roll a one and a six. They are mutually exclusive.3665

It has the word "or".3668

If I roll the die one time, what is the probability that I am going to get one or a six?3670

If I get the one, it excludes getting a six. If I get the six, it excludes getting a one.3674

Well, we use the addition rule. The addition rule involves adding the probability of each.3680

The probability that if two events are mutually exclusive, the probability of one of the events occurring3690

and this is for mutually exclusive events, is equal to the sum of the probability of each.3709

For example, if I roll the die one time, what are the chances I will roll a one or a six?3731

When using the addition rule, what is the probability that I am going to roll a one? 1 out of 6.3746

What is the probability that I am going to roll a six? 1 out of 6.3753

So, I add those up. I get 2/6 or 1/3.3757

The chances that I am going to get a one or a six are 1/3. Now, if I am dealing with "and", the chances that two things will happen.3761

They are not mutually exclusive then, the chances that both will happen, then, I need to use the multiplication rule.3770

Alright, so far we have talked about the very straightforward situation where with Mendelian genetics,3777

each trait is controlled by one gene, like a gene for eye color.3784

Each gene only has two possible alleles, like brown or blue, and one allele shows complete dominance over the other.3789

If the individual gets brown-eyed gene, eyes are brown. If they get the tall or brown-eyed allele, eyes are brown.3797

If they get the tall allele, the height is tall.3804

That is when we just talked about simple Mendelian genetics.3810

And on the AP test, they will often give you problems and tell you to assume that there is just these two alleles.3814

One shows complete dominance. They are just 100% penetrance.3821

But, there is a lot of more complex situations in nature, for example, incomplete dominance.3825

A classic example of incomplete dominance is Snap Dragons. Snap Dragons are flowers, and they can be red.3833

Another possibility is that they can be white, and there is third possibility.3845

Let's let red be big R. This would be for a red flower- red-flowered Snap Dragons.3849

Little r is white, so it is for Snap Dragons that have white flowers.3860

With complete dominance, you would expect that if we had big R-little r, heterozygote, that the flowers would be red.3868

It turns out, that is not how it works with Snap Dragons.3876

If we take a true breeding red Snap Dragon and cross it - the P generation - with a true breeding white-flowered Snap Dragon,3880

we get an F1 generation that is much different than expected.3892

They are heterozygotes, big R-little r, so we get a bunch of heterozygous offspring, but they are actually pink.3900

Now, this would seem to support the blending hypothesis. It is a colored part way.3913

It is like a combined phenotype, but it does not because these alleles do not change.3920

They maintain their nature, and we can see that in the F2 generation.3927

If you, then, cross some of these heterozygotes or self-pollinate them, what you will find is interesting.3933

White comes back. Red comes back, and there is some pinks.3943

Now, using our Punnett square, remember that what this cross is going to be for the F1 is the gametes will look like this.3949

And we will end up with genotypes 1 to 2 to 1, one big R-big R for every two heterozygotes, for every one homozygous recessive.3960

So, we end up with one white, which is the little r-little r, two pinks, so let's switch this order around just for consistency.3975

Those are my heterozygotes to a red.3991

This is an example of the pink demonstrates that this is incomplete dominance. Red is not completely dominant over white.4008

The white is still, somewhat, expressed, so incomplete dominance.4014

Codominance and multiple alleles can be illustrated together through one example, and that is using the ABO blood groups.4027

Before, we just talked about having two alleles per trait: tall-short; purple or white-flowered alleles; seeds could be round or wrinkled;4038

ABO blood groups; ABO blood groups; so there turns out to be three alleles: A, B and for O.4053

And the way we show these are I superscripted A, I superscripted B and then, little i.4065

So, this is the allele for A. This is the allele for B, and this is the allele for O.4074

I stands for immunoglobulin. This is an example of multiple alleles, more than two alleles for a trait.4080

It is also an example of codominance. Here is why.4087

If an individual has this A allele, on her blood cells, she will make this A antigen, so I will just draw it like this- an A antigen.4090

If she has a B allele, the B allele will code for a B antigen. The O allele does not code for either one.4108

What about the second allele? Well, if the second allele is the same, this is what you are going to see, right, for the homozygotes.4125

What about for heterozygotes? If the second allele is the O allele, you are going to see the same thing because the O allele does not code for antigens.4134

So, you are just going to see the A antigen on the surface.4147

If the individual is heterozygous, but the second allele has the O which is recessive, then, again, this is going to be blood type A.4152

This individual will be a type A blood, type B blood, type A blood, type B blood, type O blood.4165

Now, here is where the co-dominance comes in.4171

If an individual has both the A allele and the B allele, they are blood type AB because the A antigen will be expressed, and the B antigen will be expressed.4174

It is not incomplete dominance. It is not a type halfway between A and B.4191

They are expressing A, so they are type A; but they are expressing B, so they are type B, so they are actually type AB.4195

This is an example of codominance as well as multiple alleles since there are three alleles for the ABO blood group.4203

Another extension of Mendel's laws, another level of complexity, is the idea of polygenic inheritance and the idea of pleiotropy.4217

Before, what we have been talking about is just one gene per trait. There is a gene for height.4227

It could have two alleles. We talked about how it could have three alleles but just one gene per trait.4232

In reality though, there are many traits that are controlled by multiple genes. In humans, height is an example so is skin pigmentation.4238

And that is why you see these two traits. They go along a continuum.4252

It is not just that a tall parent who is 6-foot and a short parent who is 5-feet can only have tall kids or short kids. There is a continuum.4260

We see all kinds of heights, and the same with skin color from very, very light to very dark; so both of these are polygenic in inheritance.4269

Just one note as well to keep in mind when you think about genetics,4279

we are just talking about genetics and how it affects expression, but the environment can affect expression, as well.4283

A child could inherit plenty of alleles for tall height that they have the nucleotide sequence that says they should be 6-feet tall.4291

But if they do not get adequate nutrition, then, they could end up not achieving the height that is being coded for by those alleles.4300

So, just keep in mind that it is much more complex than just the genetics.4309

OK, so, polygenic means that traits are controlled by multiple genes. Pleiotropy is pretty much the opposite.4315

Here, we have several genes affecting one trait. Here, we have one gene affecting multiple.4322

So, this is an example here of polygenic with multiple genes controlling it.4329

In pleiotropy, we could have one gene that affects several traits. An example is the phenotype of red hair, light skin pigmentation and freckles.4334

This is due to a variant of a gene that encodes the melanocortin 1 receptor, and a variant of that gene will not just change one trait.4350

It will not just give red hair or light skin. It actually controls multiple traits, so polygenic inheritance and pleiotropy.4364

Epistasis is another concept you should be familiar with, and this is when a gene at one locust affects the expression of a gene at another locust.4374

This is not the same as just dominant and recessive alleles.4381

When we talk about dominant and recessive alleles, we are talking about alleles at the same genes.4384

So, brown is dominant over blue eye color, but we are saying those are at the same loci.4389

Here, we are talking about one gene totally in a different place on the chromosome affecting another gene.4395

And what can happen is one of these genes can mask the expression of another gene.4402

We say that the expressed gene is epistatic. We say that this gene is the one that is expressed.4407

It is epistatic to another gene. Hypostatic is the one that gets masked.4414

A classic example is coat color in Labrador retrievers.4424

Labradors can have black coat color, black labs, yellow labs and chocolate labs, so chocolate or brown, and they could also have yellow coat color.4431

Coat color is controlled by two loci, and one is epistatic to the other.4444

The first locus determines whether or not the color will be black or brown depending on what happens at the second loci.4450

So, first just looking at this first locus. This first locus, what we have is the dominant allele, big B,4461

which would code for black coat color and the recessive allele, little b, that would code for chocolate coat color.4469

If an individual has one big B, it does not matter what the second is, coat color will be black.4480

They could be big B-big B or big B-little b, heterozygous- black coat color.4487

They may be, I say may because it depends on the second locus what actually happens.4494

If the first locus has two of the recessive alleles, the individual, the Labrador, will be chocolate if they have a certain genotype at the second allele.4501

The second locus has to do with...it controls the deposition of the pigment.4514

This first allele says what the pigment will be. Will it be pigment that will make black coat color or chocolate coat color?4526

The second locus controls whether the pigment actually ends up in the fur.4533

There are two possibilities: dominant allele, which the pigment is deposited.4539

So, if an individual is homozygous dominant or heterozygous, the pigment can be deposited.4549

If the individual is homozygous recessive, the pigment is not deposited.4554

OK, so, let's see the possibilities here. Let's say an individual is big B-big B.4565

If they have an E, it does not matter what else if they have a little e or big E.4574

But if they have one E, their coat color will be black because it is black pigment, and it is being deposited in the fur.4580

If they are big B-little b, E anything, black coat color will occur.4587

If the individual is little b-little b, that is chocolate coat color. If they have E and anything else, chocolate.4595

So, it does not matter. This second one could be E.4604

It could be big E or a little e. It does not matter what the second is.4608

They just need the one allele because it is dominant.4610

Now, let's say that the individual at the second locus is homozygous recessive. Then, no matter what is over here, it will be a yellow lab.4612

It does not matter if it is big B-big B, big B-little b. No matter what, if they are not depositing this color from this first locus, they are yellow.4624

Therefore, what is happening here is masking what is happening at the first loci.4634

So, we say that this locus no. 1 is hypostatic, and this second locus is epistatic.4640

This is an example of epistasis. Again, this is going beyond just the basic Mendelian rules of inheritance.4650

What we are going to do now is practice some problems based on what learned starting with example one.4658

Assume that eye color and height are inherited in a simple Mendelian manner.4664

The alleles for eye color are represented by big B and little b with brown-eyed color dominant, so I am going to start doing some notes.4670

Big B is brown- dominant, and blue eye color is recessive, so little b is blue.4679

The alleles for height are represented by big T and little t with tall height dominant and short height recessive.4688

If a man and a woman are heterozygous for both traits, and they have a child, so we have a man who is heterozygous for both traits,4699

and he and a woman, who is heterozygous for both traits, have a child, what is the probability that here, she will be short and have blue eyes?4711

And what is the probability the child will be tall and have brown eyes?4729

Well, short and blue eyes, since these were assuming simple Mendelian inheritance, these traits assort independently.4733

They are independent events, and I can use my multiplication rule.4743

First, I am just going to address short, chances of being short. Well, height is T-T times T-T.4747

Dad is a heterozygote. Mom is a heterozygote, and in order to be short, the child would have to have both little t-little t.4760

What are the chances that the father will donate a little t? Well, 1 out of 2.4774

What are the chances that the mother will donate a little t? 1 out of 2.4783

What are the chances that the father and the mother will donate little t and the chance of both these events occurring? 1/4- we multiply.4789

Alright, that is the chances of being short. The chances of being blue-eyed, same, by the same logic.4801

So, for the blue eyes, little b-little b is blue. The chances of inheriting the blue-eyed allele from the father? 1/2.4809

The chance of inheriting the blue-eyed allele from the mother? 1/2. The chance of inheriting both, this and this are 1/4.4820

Now, I want to know the chance that this individual will be short and have blue eyes. The chances of being short are 1/4.4829

The chances of having blue eyes are 1/4, so the chances of being short and the chance of being blue-eyed multiplied is 1/16.4837

That is the chance of having the genotype little t-little t, little b-little-b.4850

And if you look back at your Punnett square for a dihybrid cross, you will see that this is indeed correct.4855

What is the probability that the child will be tall and have brown eyes?4861

Well, actually, we are going to do this one another way. There is quicker way to do this.4865

Recall the phenotypic ratio 9:3:3:1 for a dihybrid cross. This would be dominant-dominant, so tall-brown.4868

That is the 9, and here, we have what we just saw, we could have done it this way, as well.4882

Short with blue eyes, I see, is 1 out of a total of 9, 10, 11, 12, 13, 14, 15, 16, so 1 out of 16, we said short and blue.4887

Tall and brown, the chances are 9 out of 16 because they are asking me phenotype, not genotype, so I can just do it this way.4899

Chances of tall with brown eyes are 9 out of 16. Chances of short with blue eyes are 1 out of 16.4908

Example two: a man has type A blood. His mother has type O blood, and his father has type A blood.4916

The man's wife has type AB blood.4926

What are the possible genotypes of their offspring, and what phenotype is associated with each of the genotypes?4928

We take this one step at a time.4935

We know that the man has type A blood, and we eventually want to figure out the possible genotypes of the offspring and phenotypes.4938

What is this man's genotype? Well, if he has got type A, so there is two possibilities for type A blood.4946

He could be homozygous for the A allele, or he could be a heterozygote; and the second allele is an O allele.4956

To figure out what he is, we have to figure out what his parents are.4966

His mother has type O blood, so the man right here, and here are his parents, his mother, she is O, and his father is A.4970

So, I know that his father also have this A allele.4986

O, recall that type O blood is recessive, so the mother has to be homozygous recessive. Therefore, the man has to be heterozygous.4990

He got the A from his father. From his mother, the only thing he can get is the O allele.5003

So, now, I have determined this man's genotype, and the wife has type AB blood.5009

He is a type A. The wife is type AB.5018

Recall that type AB means that she has an A allele and a B allele. Now, we are finally down to the genotypes of the man and the wife.5022

What are the possible genotypes of their offspring?5033

In a simple cross like this, go for a Punnett square.5037

Here, we have the man. I am going to put him right here.5044

He has gametes that will either be the A allele or the O allele. The woman, the mother of the offspring, she is right here.5046

Her gametes will be either of the A allele or the B allele.5058

So, the possibility for their offspring could be homozygous for the A. It could be heterozygous with an A and an O.5062

It could have an A allele and a B allele, or it could have a B allele and an O, so these are the genotypes.5073

What phenotype is associated with each? Well, here, type A blood.5082

Here, A is dominant over O- type A blood. Here, we have codominance, so the blood type is type AB blood.5089

And here, we have B dominant over O, so blood type would be type B.5100

Example three: a scientist is studying pea plants, and one of the plants has round seeds.5110

In pea plants, round seeds are dominant, and wrinkled seeds are recessive.5116

I am going to have round, since this dominant will be big R. Wrinkled is going to be little r because wrinkled seeds are recessive.5121

The scientist wants to determine the genotype of the pea plant.5132

So, one plant has round seeds, and she wants to determine the genotype of that pea plant so round-seeded plant.5138

Since round is dominant, I know that the plant has one dominant allele, but I do not know what the second is.5152

This plant could be homozygous dominant or heterozygous.5161

What type of cross can he perform to determine this, so the scientist wants to determine the genotype of this plant.5170

How can he do it through a cross? What are the possible outcomes of this cross, and what would they indicate the genotype to be?5177

Well, recall that a test cross will tell me the genotype of a dominant plant, a plant with a dominant phenotype.5187

This plant has the dominant phenotype, round, and an unknown genotype.5197

So, what I am going to do is I am going to cross this plant that I want to study with the plant that is wrinkled-seeded.5203

And I know that the wrinkled-seeded plant is homozygous recessive because that is the only way you will end up with the recessive phenotype.5215

What are the possible outcomes of this cross? Well, there is two possibilities.5225

Possibility one is that the plant I am trying to figure out is actually homozygous dominant, and then, here is my homozygous recessive plant.5228

I do the cross, and then, what I would see are offspring that have all round seeds.5246

The second possibility is that the plant I am testing, trying to figure out, actually has a big R and a little r.5256

So it is a heterozygote and then, the homozygous recessive I crossed it with, and what I would see in this case is that these two plants would be round.5269

These two would be wrinkled, so it is ratio. It is probability.5281

So, I would see half the plants would have round seeds, and half would have wrinkled because half would be heterozygotes. Half would be homozygotes.5285

If I have got plenty of offspring and looked at them, and they all had round seeds, I would know that the genotype is homozygous dominant.5298

If I looked at the plants, and about half had wrinkled and half had round, I would know that I was working with a heterozygous plant.5306

Example four: coat color in mice may be black, brown or white. Coat color is controlled by two loci.5315

The first locus has two possible alleles with black dominant to brown, and these may be represented as big B and little b.5323

Alright, so we have two loci, and then, this is going to be the first loci; and it has big B and little b, and black is dominant to brown.5333

Big B is the allele for black coat color, and little b is the allele for brown coat color.5347

There is a second locus, and this locus controls the deposition of melanin; and it has two alleles possible.5354

There is a dominant allele, big C, and this allows for deposited melanin.5363

Little c is recessive so not deposited, and mice with little c-little c, their recessive homozygous genotype are albino. They have white coats.5374

OK, this is similar to the situation with the Labradors. We are talking about epistasis that little c-little c, it does not matter what you have at the first locus.5390

If you have little c-little c, no matter what you have here, these are going to end up being albino mice.5404

Determine the probability of two mice that are heterozygous for both loci producing an offspring that is albino, OK, heterozygous for both loci.5418

So, we have a mouse that is big B-little b, big C-little c, so this is a dihybrid cross, and big B-little b, big C-little c- heterozygous for both loci.5429

And I want to know the chance that the offspring will be albino.5445

Well, in order for the offspring to be albino, all of that matters is that they inherit this.5451

So, this problem is not as complex as it looked at first because I do not even have to pay attention to what is happening here.5458

It does not matter what is happening in there.5463

All I have to do is say "OK, what are the chances of this offspring receiving a little c from one parent and from the other parent?".5465

So, I am just going to treat this as a monohybrid cross: little c-little c times little c-little c.5478

The chances of inheriting the little c from this parent are 1 out of 2, and so I multiply.5486

The chances of inheriting the little c from the second parent are 1/2, 1/4.5493

So, the chance that offspring will be albino is 1 out of 4, and I could have just also done a Punnett square for this monohybrid cross or use probabilities.5500

And I see that 2 out of 4 or 1/2 are going to be albino.5514

OK, that concludes this lecture on Educator.com on Mendelian genetics.5521

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