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Dr. Carleen Eaton

Dr. Carleen Eaton

Plant Structure

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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 (7)

1 answer

Last reply by: Abdullah Farajallah
Sun May 26, 2019 2:54 AM

Post by Muna Lakhani on May 18, 2013

Are only vessels elements cells dead and cannot divide, or both tracheids and vessel elements cannot divide?

0 answers

Post by Jonathan Aguero on February 26, 2013

29:00

1 answer

Last reply by: Dr Carleen Eaton
Sun Mar 3, 2013 5:15 PM

Post by Jonathan Aguero on February 26, 2013

I thought dicots vascular part was scattered?

1 answer

Last reply by: Dr Carleen Eaton
Tue Mar 13, 2012 11:46 PM

Post by John Wadsworth on March 13, 2012

great job

Plant Structure

  • Roots anchor the plant to the ground. They are also the site of absorption of water and minerals from the soil and a site of food storage.
  • The leaf is the primary site of photosynthesis in most plants. The outer layer of the leaf is covered with a cuticle to prevent the loss of water. The cells of the mesophyll contain numerous chloroplasts where photosynthesis takes place.
  • Stomata are pores on the surface of leaves that allow for gas exchange. Guard cells flanking a stoma change shape in order to control the opening and closing of the stoma.
  • The xylem conducts water and minerals from the roots to the rest of the plant. The xylem is composed of tracheids and vessel elements arranged in chains.
  • The phloem conducts nutrients from sites of production to the rest of the plant. Companion cells associated with the sieve-tube elements regulate the flow of nutrients.
  • Plants can grow indefinitely due to the undifferentiated, embryonic cells in their meristems. Primary growth increases the length of the plant. Non-herbaceous plants also undergo secondary growth, which results in an increase in width.

Plant Structure

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
  • Plant Tissue 0:05
    • Dermal Tissue
    • Vascular Tissue
    • Ground Tissue
  • Cell Types in Plants 2:14
    • Parenchyma Cells
    • Collenchyma Cells
    • Sclerenchyma Cells
  • Xylem 5:04
    • Xylem: Tracheids and Vessel Elements
    • Gymnosperms vs. Angiosperms
  • Phloem 8:37
    • Phloem: Structures and Function
    • Sieve-Tube Elements
    • Companion Cells & Sieve Plates
  • Roots 10:08
    • Taproots & Fibrous
    • Aerial Roots & Prop Roots
    • Structures and Functions of Root: Dicot & Monocot
    • Pericyle
  • The Nitrogen Cylce 18:05
    • The Nitrogen Cycle
  • Mycorrhizae 24:20
    • Mycorrhizae
    • Ectomycorrhiza
    • Endomycorrhiza
  • Stems 26:53
    • Stems
    • Vascular Bundles of Monocots and Dicots
  • Leaves 29:48
    • Blade & Petiole
    • Upper Epidermis, Lower Epidermis & Cuticle
    • Ground Tissue, Palisade Mesophyll, Spongy Mesophyll
    • Stomata Pores
    • Guard Cells
    • Vascular Tissues: Vascular Bundles and Bundle Sheath
  • Stomata 36:12
    • Stomata & Gas Exchange
    • Guard Cells, Flaccid, and Turgid
    • Water Potential
    • Factors for Opening Stoma
    • Factors Causing Stoma to Close
  • Overview of Plant Growth 44:23
    • Overview of Plant Growth
  • Primary Plant Growth 46:19
    • Apical Meristems
    • Root Growth: Zone of Cell Division
    • Root Growth: Zone of Cell Elongation
    • Root Growth: Zone of Cell Differentiation
    • Stem Growth: Leaf Primodia
  • Secondary Plant Growth 48:48
    • Secondary Plant Growth Overview
    • Vascular Cambium: Secondary Xylem and Phloem
    • Cork Cambium: Periderm and Lenticels
  • 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

Transcription: Plant Structure

Welcome to Educator.com.0000

In this section, we are going to be focusing on plant structure.0002

And I am going to start out by talking about the different tissue types that are found in a plant.0005

There are three types: the dermal tissue, vascular tissue and ground tissue.0010

The outer covering of a plant consists of dermal tissue, so the epidermis. Epidermal cells are an example of dermal tissue.0016

The epidermis provides a protective covering on the plant, and it also secretes a waxy layer called the cuticle.0028

And that prevents water loss from the plants, so that is one type of tissue.0036

The second is the vascular tissue. The vascular tissue is composed of the xylem and phloem.0041

And we will talk in detail about the xylem and phloem in a few minutes.0049

For now, though, you should just know that the xylem transports water and0053

minerals throughout the plant from the roots up through the stem and leaves.0057

The phloem transports nutrients from where they are created via photosynthesis in the leaves.0062

It transports those nutrients from the site of their creation in the leaves to the rest of the plant, these carbohydrates.0069

And the region, the areas containing vascular tissue are...if you cut through a cross-section, you can see that they are arranged in these cylinders.0076

And these cylinders are known as vascular cylinders that contain vascular tissue.0086

The third type of tissue is the ground tissue. The majority of the plant is ground tissue.0093

Ground tissue is the site of photosynthesis. It is also important for support of the plant, and it is the site of storage of water and nutrients.0098

All three types of tissue are found throughout the plant. For example, the roots, leaves and stem all have a covering composed of dermal tissue.0110

The vascular tissue, the xylem and phloem, runs throughout the plant from the roots0119

up through the stem and leaves to deliver nutrients and water to all areas of the plant.0123

Delving a little deeper going from tissue to the cellular level of organization,0130

there are three major cell types in plants that I am going to talk about right now.0135

And those are the parenchyma, sclerenchyma and collenchyma.0140

Parenchyma cells have a primary cell wall that is thin and flexible, so they have a thin, flexible primary cell wall.0147

However, they lack a secondary cell wall.0165

Often, when people imagine a plant cell or when we talk about a plant cell, what we are talking about is the parenchyma.0169

They are thought of as this is the typical plant cell, and they have a large central vacuole usually.0174

They are specialized depending on their location. So, a parenchyma cell in the leaf would be specialized to carry out photosynthesis.0182

Those in the roots are a site of storage for starches within plastids.0188

Parenchyma cells retain the ability to divide. Therefore, if a plant is injured, repair can occur through division of parenchyma cells.0193

The second type of cell are...let's talk about the collenchyma cells next.0202

Collenchyma cells also lack a secondary cell wall. They have primary cell walls of varying thickness.0208

One region will be a little thicker, the other a little thinner but no secondary cell walls.0219

And their function is to support the stem as the plant is growing. An example of collenchyma cells are the strings that you will find in a stalk of celery.0231

Finally, sclerenchyma cells, these cells have a thick primary cell wall, and a thick secondary cell wall, thick primary and secondary cell walls.0240

The secondary cell wall contains lignin. It provides a lot of strength, and the function of a sclerenchyma cell is to provide support to the plant.0257

You should be aware that there are two types of sclerenchyma cells: fiber cells and sclereids.0271

Fiber cells are longer and thinner than the sclereids, so fibers are longer and thinner. The sclereids are shorter and more than irregular shaped.0277

An example of fiber cells are flax. Flax fibers are used to make linen.0290

An example of sclereid cells...you know how a pear has that gritty feel? That is due to sclereid cells.0296

Next, we are going to talk about the xylem and then, the phloem.0305

So, remember, vascular tissue is composed of xylem and phloem. Right now, I am focusing on the structure.0308

We are going to talk about transport of nutrients in water throughout the plant in a later lecture. Right now, the focus is on structure.0313

General features and just talking about vascular tissues, recall from the previous lecture,0323

while nonvascular plants like moss have certainly some adaptations that allow them to live on land,0329

tracheophytes or vascular plants evolved even further to adapt to new environments and to succeed in terrestrial environments.0336

Vascular systems and their supporting structures contain lignin, and that is the polymer that strengthens the cell walls in these plants0345

and allows them to grow very tall and also provides a structure through which water and nutrients can reach all areas of the plant.0356

In addition, vascular plants have true roots, stems and leaves.0366

First, talking about the xylem, the job of the xylem is to conduct water and minerals from the roots to the rest of the plant.0374

And there are two types of cells that compose the xylem: tracheids and vessel elements.0382

And these are arranged in chains, and the result is that they form essentially tubes through which0389

water can be conducted from the roots up through to the leaves, to the stem, to all parts of the plants.0396

Tracheids are long and thin. Vessel elements, they tend to be shorter and fatter.0404

They are represented as, kind of, similar with hair, but usually the vessel elements are a little shorter and fatter than the tracheids.0411

Something else to note is that these cells are dead. They cannot divide, so they can do their job of conducting water, but they can no longer divide.0417

So, they have lost the ability to divide. Now, they have these thick secondary cell walls, but the water needs to be able to go from cell to cell.0428

And the solution in tracheids is these areas called piths, and water can flow from cell to cell via these piths.0437

These piths lack secondary cell walls, so they are regions of the tracheid that lack secondary cell walls, and they allow water to move from cell to cell.0450

The vessel elements are lined up end to end and have openings through which the water can pass. That is shown right here.0463

Also, tracheids are found in both non-flowering plants, gymnosperms and in angiosperms.0474

However, only angiosperms generally have vessel elements.0484

So, gymnosperms, which are non-flowering plants, they are vascular. They are seed plants, but they are non-flowering.0489

They only have tracheids, whereas, angiosperms have both cell types.0498

So, that is the xylem.0514

The second type of cell found in vascular tissue is the phloem, and the phloem conducts nutrients from the leaves to the rest of the plant.0515

And it is composed of what is called sieve-tube elements and companion cells.0524

So, the sieve-tube elements are the cells through which the nutrients actually move through.0534

Up in the leaves, photosynthesis occurs. Glucose and carbohydrates are made, and those move down through the phloem.0542

The sieve-tube elements are accompanied by companion cells.0552

And the companion cells are located near plates called sieve plates through which the nutrients can move.0557

And the job of the companion cells is believed to be to regulate the flow of the nutrients through the sieve-tube elements through the sieve plates.0569

So, companion cells are associated with the sieve-tube elements and provide supporting0578

function and allow for regulation of the flow of nutrients through these cells, OK?0589

So, xylem conducts water, and phloem conducts nutrients.0598

Now, we are going to go ahead and talk about the different systems in the plant.0603

OK, there are two major systems in the plant: the root system and the shoot system. The root system is largely below ground.0609

And the shoot system are the parts of the plant that are above ground such as the stem, leaves and flowers.0615

The root is a structure that anchors the plant to the ground. It is also the site of the absorption of water and minerals, and a site of food storage.0622

Two major types of root systems are tap roots and fibrous roots.0631

With tap roots, there is a single large root from which lateral roots called branch roots arise, and tap root systems penetrate deep into the ground.0639

Carrots are tap roots for example. Carrots or turnips and other root vegetables are also an0654

example of what is called a storage root because they are a site of long-term storage of food.0660

Fibrous roots have a different structure. Fibrous roots are bound in grasses such as wheat.0665

They are thinner, and they are more spread out to form a mat, and they do not penetrate as deep.0671

They do not have a single main root. They are more spread out, so it is more of a mat or net of roots.0678

And what is very important about these roots is that they also prevent erosion of the soil.0690

Because they are thin and spread out like this, they help to hold the soil down and prevent erosion.0696

Other types of roots that are specialized, one is aerial roots.0702

So, although I said for the most part, the root system is below ground, there are some exceptions.0707

Plants such as ivy cling to the sides of buildings and trees, so aerial roots allow plants to attach to these surfaces and grow up along a vertical surface.0712

Another type of root that extends above ground are prop roots.0722

Prop roots grow from the base of the stem, and they help support a plant like corn0726

that is tall and, sort of, heavy on top and might fall over without the support.0730

If this is the ground, and then, you have a plant growing up, a tall, sort of, heavy plant, what prop roots do is they come out from the base of the stem.0735

They grow from the base of the stem and into the ground, and they hold - literally prop up - the plant.0750

This prop root is a type of adventitious root.0760

So, adventitious roots arise from the stem, branch or another area of the plant other than the primary root.0763

Prop roots are adventitious roots because they do not originate from the primary root. They grow out from the stem of the plant.0774

Next, we are going to look at the structure of a cross-section of the roots and the different structures within monocots and dicots.0782

First, starting from the outer layer, we talked about dermal tissue, and dermal tissue is, it forms the epidermis.0796

The epidermis is right here. This is an outer covering, and in roots, the epidermal cells have projections called root hairs.0807

Root hairs are projections of epidermal cells.0815

And their function is to increase the surface area of the root, which makes sense because the job of the root is absorption.0819

This increased surface allows for absorption.0826

Now, seeing that there are two different structures here, this is a monocot. Remember that angiosperms can be divided into monocots and dicots.0830

Flowering plants can be divided into monocots and dicots.0838

Slightly different structure of the vascular tissues of a monocot versus a dicot, OK, the epidermis found in both, that is the outer covering.0841

Next, what you will see is the cortex, and the cortex is composed of parenchyma cells.0852

These cells contain plastids where starch is stored, so cortex cells, which are parenchyma, and they are a site of storage.0860

The cortex is also right here on the monocot.0873

The pith, these are similar cells, but the difference between cortex and pith is that cortex lies outside the vascular cylinder.0878

Whereas, pith lies within the vascular cylinders.0888

So, it is more of the location versus the function, but pith also functions as a site of storage.0891

Now, roots do not undergo photosynthesis.0898

They are non-photosynthetic parts of the plant, and they depend on the leaves to make the carbohydrates.0901

And these are transported by the phloem. Meanwhile, the xylem is transporting the water absorbed from the roots up to the rest of the plant.0908

And these vascular tissues are found in what is called the vascular cylinder, so this entire structure is the vascular cylinder.0917

This layer right here, this black line, represents what is called the endodermis. This is a layer of cells.0933

This whole thing is the vascular cylinder, all these structures, but surrounding it is this endodermis.0943

So, this is just a layer of cells, and the purpose of the endodermis, one purpose is to regulate the entry of water and minerals into the xylem.0956

These endodermal cells, to carry out this job, are packed tightly together, and along the endodermal cells is a structure called the Casparian strip.0965

And this is a belt made of a waxy substance called suberin.0977

Some of the endodermal cells have suberin impregnated in areas of their cell wall, and the result is this strip that is impermeable to water.0983

This means that water cannot just come up to the root and then, just go straight into the xylem, be transported around. It is actually regulated.0993

And because of this Casparian strip, water cannot slip past the endodermal cells.1002

In a later lecture on plant nutrition, I am going to talk about how this regulation1007

occurs and how transport of water and nutrients occurs throughout the plant.1012

Just inside the endodermis is a layer of cells called the pericycle, so we will draw that in right inside the endodermis, the pericycle.1018

And this is the site from which the lateral roots arise.1027

Now, within the vascular cylinder are xylem and phloem.1037

In the monocots, what you see is a circle of xylem here, so the xylem is marked in brown, circle of xylem, and just outside of that, a ring of phloem.1044

In dicots, the structure is different. It is this star or X-type structure of xylem with the phloem located just outside that.1056

So, remember, the central area of parenchymal cells is called the pith. The outer area of parenchymal cells is called the cortex.1065

This is just to give you an idea of the cross-section- what the root structure is if you took a root, cut it and looked at a cross-section in a monocot and a dicot.1074

While we are talking about roots, it is a good time to introduce the nitrogen cycle.1084

And I am going to focus mainly on the plants and how they obtain nitrogen, but remember that they are part of the overall nitrogen cycle.1088

Right now, though, our focus is on plants.1099

The atmosphere is about 78% nitrogen. However, the nitrogen in the atmosphere is dinitrogen N2, and this is a gas.1101

It is not a form that plants can utilize, but nitrogen is needed by plants and other organisms.1110

Plants use it to make proteins, nucleic acids and other organic compounds, so nitrogen is a very important part of organic compounds.1116

Here, we have in the atmosphere, N2, dinitrogen gas. That ends up in the soil.1128

Bacteria play an extremely important role in the nitrogen cycle because what they are capable of doing1135

- nitrogen-fixing bacteria - is converting this gaseous nitrogen in the atmosphere to ammonia, NH3.1141

So, nitrogen-fixing bacteria can take the dinitrogen and convert it to ammonia.1149

I am going to talk here about legumes in a second. Right now, I am talking about nitrogen-fixing bacteria that are free-living.1155

These are in the soil, and these are free-living nitrogen-fixing bacteria.1162

Within the soil are free hydrogen ions, H+, and these combine with the ammonia to create ammonium ions, NH4+.1167

Nitrifying bacteria can take that ammonia and oxidize it to form nitrite.1181

So, nitrifying bacteria take the ammonia and convert it to nitrite, NO2- and then, further convert, oxidize that to nitrate, NO3-.1190

Alright, so, what has happened so far is nitrogen-fixing bacteria converted the N2 to ammonia.1204

The ammonia combined with hydrogen ions in the soil to make ammonium, NH4+ ions.1210

Then, nitrogen-fixing bacteria oxidized that to nitrite and then, further to nitrate.1221

And this is a form that the plants can absorb and then, convert back into ammonium and use.1233

Now, I do want to note that plants can absorb some ammonium from the soil, but most of the nitrogen they absorb is in this form of nitrate.1242

And in fact, if the ammonia level of the soil gets too high, it is actually toxic to plants.1253

The plants really depend on bacteria to fix nitrogen and then, convert it to nitrate.1260

Denitrifying bacteria actually take some of the nitrate that is created by the nitrifying1269

bacteria and end up releasing nitrogen gas that just goes back up into the atmosphere.1275

Second thing I want to talk about are nitrogen-fixing bacteria that exist on the root nodules of legumes.1286

A group of plants called legumes have a mutualistic relationship with bacteria, and the bacteria are from the genus Rhizobium.1293

These Rhizobium live in close association with legumes like pea plants.1306

Legumes have root nodules, and within the root nodules, within the cells of the root nodules, are bacteria and vesicles, and the bacteria fix nitrogens.1311

They perform this function of changing it from N2 to NH3 for the plant.1324

What the Rhizobium get from this association is protection and nutrition from the plant. The plant gets a supply of nitrogen.1331

Now, while we are focusing on plants right now, just to complete the discussion, which we will take up in ecology section about the nitrogen cycle,1339

so the plants get their nitrogen one way or another, and make it into organic compounds and survive and live.1349

Well, animals eat the plants, and the animals release waste products; and the animals also die and decay.1357

In addition, plants die, and their organic matter is returned to the soil.1368

And within the ground, decomposers break down the waste products and parts from dead plants1373

and animals and return that nitrogen to the soil where it is acted upon by nitrifying bacteria.1382

So, in that way, the nitrogen has been incorporated into plants,1387

gets incorporated into the animals and makes its way back into the soil to complete the cycle.1391

One other thing is just to look at the overall reaction of nitrogen fixation, so this is nitrogen from the atmosphere.1396

Nitrogen gas combines with 16 molecules of ATP plus 8 electrons plus 8 hydrogen ions to yield 2 molecules1403

of NH3, ammonia, plus 16 molecules of ADP plus 16 inorganic phosphates plus hydrogen.1415

You do not need to memorize these, but just to look at the overall reaction to see what is happening,1427

that fixation of nitrogen is an energy-requiring process.1432

And the result is that nitrogen from the atmosphere is converted to ammonia that the nitrifying bacteria can act upon.1436

So, that is the nitrogen cycle, and you see this relationship between bacteria and plants that allows the plants to grow and thrive.1445

A second relationship between plants and another organism is a relationship between plants and fungi.1454

We talked about this in the lecture on fungus.1460

And a mycorrhiza refers to the symbiotic relationship between certain fungi and the roots of a plant.1464

Plural is mycorrhizae, and mycorrhizae provide the plant with an increased surface area.1473

The advantage to a plant that has mycorrhizae associated with it is that it has a1481

bigger surface area that can be used to absorb water and minerals from the soil.1485

Certain fungi have a special type of hyphae that allows them to extend over the root surface and actually partly into the root.1492

I said the advantage for the plant is that this increases the surface area of the root.1502

And the fungus, then, helps the plant root to absorb water and minerals.1506

The added benefit to the fungus is that they take carbohydrate from the root cells, and that allows them to live.1510

In addition, some of these fungi secrete growth factors that help the plant to grow.1517

Mycorrhizae are very commonly associated with plants, and in fact, over 90% of plants have mycorrhizae associated with them.1523

And experiments have been done growing certain types of plants with and without mycorrhizae.1530

And those plants with mycorrhizae grow significantly better than those without them.1536

There are two types of mycorrhizae: ectomycorrhiza and endomycorrhiza.1541

Ectomycorrhiza are a type of mycorrhiza in which the hyphae remain outside the root cell, so hyphae outside the root cell.1563

In this case, the fungus are confined to the extracellular space of the cells in the cortex of the root.1578

In endomycorrhiza, the hyphae actually enter the cell walls. Hyphae enter the plant cell walls.1586

But they do not actually penetrate the cell membrane or enter the cytoplasm of the cell so just two subtypes of mycorrhizae.1597

OK, so we talked about root structure. We also talked about associations between roots in bacteria and roots in fungus.1605

The next part of the plant we are going to focus on are the stems.1612

The stems contain nodes, and these nodes are a point of attachment for the leaves; so these are points of attachment for the leaves.1617

Like the roots, the stem is covered with a layer of dermis.1639

So, if we took a root and cut it or a stem and cut it and got a cross-section of the stem, we would see this dermal tissue.1644

Or epidermis is the outer layer, so the epidermis is the outer layer, and this is continuous.1654

The root is covered with epidermis that continues up on the stem and then, out to the leaves.1661

In addition, the vascular system is continuous, as well.1667

So, we talked about the roots absorbing water and that water being carried up through the stem to the leaves.1670

Meanwhile, the phloem is absorbing nutrients that were made in the leaves and carrying those down through the stem to the roots.1674

Now, again, there is a difference between the arrangement in the vascular bundles of monocots and dicots.1684

And we talked about the roots of monocots and the roots of dicots and how those are structurally different.1691

Here in monocots, the vascular bundles are scattered throughout the stem.1699

So, if this is a monocot, then, you would find these vascular bundles throughout.1711

Contrast that with a dicot of the stem. Take the stem of a dicot.1717

You cut it into a cross-section, and then, what you are going to see is that the vascular structures, the vascular bundles, are arranged in a ring.1722

Remembering that in a stem in dicots, the vascular bundles are arranged in a ring.1735

Whereas in monocots, the vascular bundles are just scattered throughout.1743

The cortex is unspecialized tissue that lies between this epidermis and the vascular or conducting tissues.1750

So, we talked about the cortex earlier on. It can be a site of storage.1760

It could be a site of photosynthesis depending on the area of the plant.1765

The cortex, the pith is a central area of parenchymal cells.1770

So, the main point about the stems that you should know is that there is a difference in the vascular bundles between dicots and monocots1775

and also that the nodes are points of attaching for the leaves, and leaves are the structure that we are going to talk about next.1782

The leaf is a primary site of photosynthesis in most plants.1791

Now, there are exceptions. For example, in some cacti, a lot of the photosynthesis takes place in the stem.1795

And in fact, in cacti, leaves may be modified to form spines, and those spines are great protection for the cactus and minimize water loss.1801

The flat part of the leaf is called the blade, and the petiole is this little stock that attaches.1813

So, if you have a leaf, if you pull the leaf off of a tree, and this part will be the blade.1826

And then, the petiole is the part - the little stock - that attaches the leaf to the stem.1832

Like the root, the outer layer of the leaf and like the stem, as well, the outer layer is the epidermis.1839

So, here is a cross-section of a leaf, a close-up view, a cross-section of the leaf.1846

And here, this outer layer is the upper epidermis, so the top of the leaf, the upper epidermis.1852

And down here, protecting the leaf on the underside, is the lower epidermis1862

The epidermis produces a cuticle. The cuticle is a waxy...if you feel leaves, they have, sort of, a waxy feel.1873

And that waxy layer prevents the water loss from the plant.1879

The epidermal cells secrete a substance that comprises the cuticle, a waxy layer that prevents water loss.1885

The middle of the leaf is composed of ground tissue and vascular tissue.1896

We are going to talk about the ground tissue first. The ground tissue, these are the mesophyll cells.1902

And as you can see, there are two different types of mesophyll cells.1913

And these right here, these more columnar cells, are known as the palisade mesophyll or palisade parenchyma.1918

Here, we have a second layer of mesophyll cells, and these are known as the spongy mesophyll cells/layer.1934

The mesophyll cells contain many chloroplasts because these are the site of photosynthesis.1946

And starting out by contrasting the shape and the arrangement of the palisade versus the spongy mesophyll,1960

in the palisade mesophyll, the cells are columnar, and they are much more tightly packed than the spongy layer.1966

The irregularly shaped spongy mesophylls are purposely less tightly packed to allow for these air spaces.1972

And what the air spaces do is that they allow for gas to diffuse up and reach the cells throughout the leaf.1984

The circulation of gases for photosynthesis to occur, CO2 needs to go into the cell, and oxygen needs to be released.1991

So, there needs to be circulation of gases throughout these air spaces.1998

The underside of the leaf, in particular, contains pores called stomates or stoma singular, stomata plural or sometimes stomate.2004

The upper area can contain these, as well, but it is shown here in the lower.2016

And the purpose of a stoma is to allow for gas exchange, so CO2 needs to enter the plant, go into the cell.2020

Photosynthesis occurs. Oxygen needs to be released.2030

But because the epidermis is covered with this cuticle layer, which prevents water from leaving, it also prevents gas exchange from occurring.2034

So, that is why there are these stoma, which are pores.2046

I am going to talk about stoma in detail in a few minutes, but right now, what you should know is that they are flanked by guard cells.2053

These stoma are flanked by guard cells, and the guard cells control the opening and closing of a stoma.2061

Most of the water loss in a plant occurs through these pores, occurs through the stomata.2072

And so, the guard cells need to minimize water loss while at the same time, allowing the stomata to be open enough for gas exchange to occur.2078

Alright, we have talked, now, about the dermal tissue and the ground tissue, now, the vascular tissue.2086

So, the last part of the leaf here is what is shown, a vascular bundle or a vein, and they contain the xylem and the phloem.2093

We already talked about xylem and phloem being present in the root and in the stem, and it goes up into the leaf, the vascular bundle.2105

Within the vascular bundle, the xylem and phloem.2112

And since the nutrients in the plant, the carbohydrates, are produced here in the leaf, the phloem is going to carry those to the rest of the plant.2116

The vascular bundle is surrounded by a layer of cells called the bundle sheath, so a sheath,2123

so bundle sheath or bundle sheath cells that are just a layer surrounding the vascular bundle, and these are specialized mesophyll cells.2132

Monocots and dicots have different vascular bundle patterns or different vein patterns.2142

So, if you look at the leaves of a monocot, it is going to have a parallel structure of the veins.2147

Whereas, a dicot, it is going to be more of a net-type pattern, so parallel in a monocot versus a net-type pattern in a dicot.2157

We are going to talk more in detail, now, about stomata, so as I introduced, stomata are pores on the surface of leaves that allow for gas exchange.2173

More than 90% of the water loss from a plant is lost through the stomata.2183

To prevent this, the opening of stomata is tightly controlled by the guard cells.2188

Guard cells are modified epithelial cells, and they open and close the stoma by changing shape.2197

This picture here shows two guard cells, and it is showing this stoma as being open, so this is an open stoma.2204

And I said that the stoma or the guard cells control the opening and closing of the stoma by changing shape.2213

And what it has to do with is that when water enters a guard cell, the guard cell becomes turgid, so it is full of water.2220

And guard cells have microfibrals that are radially oriented, so they radiate out.2229

And this arrangement causes the cell when filled with water to bow outward.2240

When these cells are flaccid, they are not filled with water. They come together.2245

When they fill with water, they bow outward like this. They bend away from each other, and the result is that the stoma is open.2252

So, when the cell is flaccid, it does not have water, or it has minimal water in it. The stoma is closed.2263

When the guard cells fill with water, they become turgid. They block the opening to the stoma, and the stoma is open.2274

To understand how guard cells work, you need to understand the concept of water potential. The water potential of pure water is zero.2285

If a solution is more concentrated than pure water, it has more solutes in it, it will have a more negative water potential.2302

The most important point is that water moves from areas of higher water potential to areas of lower water potential.2309

So, water is going to go from an area of high water potential to an area of low. It is going to move from high to low water potential.2318

If pure water is zero for example, then, if a cell has a lower water potential, it is going to be more negative, then, the water is going to move into that cell.2332

Solutes are not the only factor that affects water potential. For example, pressure can affect water potential.2347

In a plant, the cell wall exerts pressure, and that could decrease the water potential from the inside of the cell as that pressure is pushing outward.2354

So, it is not just about solutes. It is about other factors, as well.2363

Now, potassium is very important in the activity of guard cells, and this ties in to water potential.2368

Because what happens is...here is a guard cell, and then, there are dermal cells nearby; and what happens is potassium is taken up by the guard cells.2374

As the potassium is taken up by the guard cells, the water potential inside the guard cell will decrease.2389

So, potassium goes into the guard cell. It is going to decrease the water potential inside the guard cell.2396

The water potential is going to become more negative, and this water will be stored within vacuoles inside the guard cell.2401

And as the water potential inside the guard cell becomes more negative, water is going to enter the guard cell.2409

The guard cells will bow outward like this, and the stoma will be open.2415

When potassium moves out of the guard cell, water is going to follow it out through osmosis, and the cell is going to become flaccid.2421

These two guard cells will be flushed together, and they will block the opening of the stoma.2430

You should know conditions that stimulate the stoma to open or to close.2436

So, factors or conditions for the opening or that stimulate the opening of the stoma, one is decreased CO2 levels within the air space of the leaf.2442

We talked about the airspace of the leaf where the gases can circulate around, and CO2 is used in photosynthesis.2463

Therefore, when the CO2 levels drop, the stoma needs to open so that more CO2 can come in.2468

Oxygen can leave, and photosynthesis can continue. Therefore, decreased carbon dioxide leads to the opening of the stoma.2475

The second factor that will cause a stoma to open is the presence of light.2484

In addition to CO2, light is needed for photosynthesis, and in fact, stoma are typically open during the day.2487

The plasma membrane of guard cells contain blue light receptors.2497

These blue light receptors, when they are stimulated due to the presence of light, will cause potassium to be absorbed from surrounding cells.2503

Water will enter the cell, and again, stoma will open.2516

The third factor is Circadian rhythm, which refers to 24 hour cycles that organisms have.2520

And plants have a Circadian rhythm, a 24 hour cycle, for the opening and closing of stomata.2529

And in fact, even if it is dark, if you put a plant in a dark area, the stomata will still open during the day and then, close at night.2536

Now, these other factors can affect it if there is light, and it is daytime, then, more stomata will open.2548

But, there is already this underlying 24 hour cycle of opening during the day, closing at night.2554

Now, these are some factors that cause the stomata to open, factors causing a stoma to close, a couple factors for that, a few factors.2560

One: decreased water. If there is not enough water available, water cannot enter the guard cells.2576

And so, even if potassium enters the guard cells, if there is not water available, the water cannot enter, and these guard cells will not bow out.2585

So, in this case, the cells will remain flaccid, and the stoma will close,2591

which is actually good because if there are conditions of low water, the stoma needs to be close to prevent further water loss.2595

Another factor is temperature. If there is increased temperature, then, the plant needs to conserve water, so if it is hot out, the stomata will close.2602

Finally, there is a hormone called abscisic acid, and abscisic acid is secreted by plants.2613

And so, it is a hormone that is secreted by plants when they are dehydrated.2627

When the abscisic acid is secreted, it stimulates the guard cells to close, so this is a sign of dehydration.2631

So, decreased water, increased temperature or increased abscisic acid, will all stimulate the stomata to close.2639

Decreased CO2, the presence of light and a Circadian rhythm, all are factors involved in opening a stoma.2648

The next area that we are going to talk about today and the final area is plant growth.2658

And I am going to start out with an overview of plant growth.2664

Plants are capable of indefinite growth. Animals, humans, grow to a certain height and then, we stop.2668

By contrast, plants can grow indefinitely, and this type of indefinite growth is called indeterminant growth.2679

Indeterminant growth is possible because of undifferentiated cells present in areas of the plant called the meristems.2687

These are embryonic cells that are actively dividing. They are undifferentiated, and because of this, plants can grow on and on.2695

Some plants have a life cycle of a year. Their lifespan is a year.2702

They grow during that year. These are annuals.2706

Whereas, perennials have a lifespan of many years and may continue to grow throughout this long lifespan.2709

With some plants like the ancient red woods, the lifespan can be over a thousand years, and they continue growing.2714

There are two types of growth that occur in plants: primary growth that increases the length of the plant.2721

The plant grows up into the air and down into the ground, and all plants undergo primary growth.2729

However, non-herbaceous plants, woody plants like trees, also undergo secondary growth.2735

With secondary growth, the plant increases in girth or width.2742

To understand the growth of plants, we need to look more closely at the meristem- the structure that contains embryonic cells.2747

And there are two types of meristems. One is an apical meristem, and these are present at the tips of roots and shoots.2754

These would be found at the tips of the roots and the tips of the shoots. These are responsible for increase in the length of the plant.2764

In contrast, lateral meristems are responsible for the secondary growth of a plant.2772

Let's start out talking about primary plant growth of roots and of stems.2779

As I said, the apical meristems are responsible for the primary growth of a2787

plant for the plant growing up towards the sky and down into the ground.2791

These are found at the tips of roots, shoots and on axillary buds, which are regions on the stem where a branch can grow from.2795

We are going to first look at the zones of growth within a root.2804

So, here is a root, and the apical meristem is located at the tip of the root.2809

And it is covered by a root cap, a structure called a root cap that provides protection.2813

And if you look at the tip of the root, you can divide it into three regions of growth or zones.2820

The first zone is the zone of cell division, and that is roughly this region right here.2825

The apical meristem is in the zone of cell division, and this is an area where mitosis is actively occurring.2835

Cell division is ongoing, and the result is new root cells will be created; and also replacement meristem cells will be created.2847

Just above that is another zone called the zone of elongation.2856

In the zone of elongation, these newly created cell elongate, just as the name suggests.2863

And as they elongate, they push the root more deeply into the soil, so it grows downward.2870

Finally, there is the zone of differentiation. Different cells have different functions.2876

Some are epidermal cells. Some are parenchyma cells.2884

And within the zone of differentiation, cells differentiate into a specialized cell type where their structure and function is determined.2887

This shows you the root structure. Here is a stem.2896

So, the shoot also undergoes increase in length, primary growth, but the apical meristem is a bit different structure.2903

And one area you should note are what is called the leaf primordia.2911

And the leaf primordia are the site from which new leaves originate from the apical meristem of the shoot system.2916

That is primary plant growth, but remember that woody plants undergo secondary plant growth, as well.2927

And secondary plant growth is an increase in the girth or width of a plant.2934

Parts of the plant that are the result of primary growth constitute what we call the primary plant body.2939

For those plants that undergo secondary growth, they have additional areas that are called the secondary plant body.2946

Secondary growth occurs at the same time as primary growth but not in the exact same spots.2954

While the plant is growing taller at the tip and adding cells at the bottom of the root,2960

meanwhile, in older areas of the plant, secondary growth can be occurring to thicken that up and increase the width.2968

They are both occurring at the same time but not in the exact same spots.2975

The site of secondary plant growth is the lateral meristems.2978

And there are two types of lateral meristems: the vascular cambium and the cork cambium.2983

So, we are going start by talking about the vascular cambium.2990

As the name suggests, the secondary xylem and secondary phloem originate from the vascular cambium.2993

The vascular cambium consists of a cylinder of parenchymal cells.3004

So if you took a cross-section of the stem, you would see a cylinder of parenchymal cells running all up and down the stem.3008

And this is the vascular cambium.3016

Secondary xylem, which is created from this, developed from this, is wood, so secondary xylem is wood; and secondary xylem has a lot of lignin in it.3020

The cell walls are very strong and provide excellent support for the plant, which is why trees can grow so tall.3035

The xylem functions, of course, in water transport and as a mean of support.3042

However, older secondary xylem eventually stops transporting water, and its only function is to support the plant.3048

So, that is the vascular cambium, xylem and phloem or secondary xylem and secondary phloem, developed from the vascular cambium.3056

The second type of lateral meristem is the cork cambium.3071

Now, primary growth of plant produces the epidermis, so that is outer layer covering the plant.3078

However, in woody plants, that epidermal layer eventually falls off and is replaced by a thicker covering like bark.3083

And this is produced largely by the cork cambium.3093

Like the vascular cambium, the cork cambium is a cylinder of cells that runs along the length of the stem.3097

So, within the cork cambium are produced cork cells, and cork cells produce a substance called suberin.3104

Suberin has a waxy consistency. I have mentioned this before, and these cork cells along with the tissues, they produce what are called the periderm.3115

This periderm covering replaces the initial epidermal covering. Periderm is cork cells plus the tissues produced by them.3127

The periderm plus the secondary phloem constitute bark, so the secondary phloem is also a part of the bark.3143

This periderm provides protection from water, so it is impermeable. The periderm is impermeable to water and to gases.3151

There are structures in bark. There are little slits or pores called lenticels, and they allow gas exchange across the periderm.3164

Secondary plant growth occurs at the lateral meristems. There are two types of vascular cambium and the cork cambium.3182

The vascular cambium is the site of production of the secondary xylem and phloem.3188

The cork cambium produces cork cells, which come along with their tissues to constitute the periderm,3192

which is an outer covering that is impermeable to water and gases.3198

Alright, so today, we covered quite a bit. We talked about plant structure as well as growth.3205

So, we are going to go ahead and do some review questions.3210

Label the following structures on the diagram of the leaf below.3213

OK, first, we have bundle sheath. The bundle sheath is a layer of cells surrounding the vascular cylinder, so the bundle sheath is right here.3217

And within that is the vascular bundle.3229

Stoma: well, a stoma is an opening or pore in the leaf that allows for gas exchange, so the stoma is right here.3233

Upper epidermis: the epidermis is the outer covering of the leaf, so this is the epidermal layer; and this is actually the upper epidermis.3246

Next, vascular bundle: so, the bundle sheath is this outer covering. This entire structure, though, is the vascular bundle.3258

Next, the spongy mesophyll: well, this is all the mesophyll layer. The ground tissue is all right here.3270

The vascular bundles are within that.3277

And these spongy mesophyll are the irregularly shaped mesophyll cells that leave room for air spaces so gases can circulate.3279

So, right here is the layer of spongy mesophyll.3288

Palisade mesophyll cells are columnar, and they are more tightly packed. That are these cells right here, so we have the palisade mesophyll layer.3295

Those are all the sections of a leaf that we are asked to label.3308

List the three types of plant tissue and their functions.3316

At the beginning of the class, we talked about three types of plant tissue. The first one is the dermal tissue.3321

The second type of tissue was the vascular tissue, and finally, we talked about the ground tissue and functions.3332

Well, a major function of the dermal tissue is to produce the outer covering of a plant.3345

The dermal tissue is the epidermis. That is one type of dermal tissue.3354

So, the outer covering or epidermis consists of dermal tissue, and these epidermal cells secrete a waxy layer, a cuticle that protects the plant.3361

The second type of tissue is the vascular tissue, and this includes the xylem and phloem.3373

And the function of vascular tissue is to transport nutrients and water.3379

Finally, the ground tissue: most of the plant tissue is ground tissue, and ground tissue is a site of storage.3390

It is a site of photosynthesis. It is also where other metabolic functions of the plant are carried out.3400

So, these are the three types of tissue and their major functions.3413

What are two factors that stimulate the opening or closing of the stomata?3420

We talked about some factors that stimulate the stoma to open and then, other factors that would stimulate it to close.3426

They only asked you for two total, but I am going to do more; so we are going to start out with factors that would cause the stoma to open.3434

What would stimulate the stoma to open? Well, decreased CO2 within the air spaces because when CO2 level is dropped,3444

it means photosynthesis has been going on and using up CO2, the plant needs more CO2 to continue, and it needs to let the oxygen out.3454

The second factor that stimulates that stoma to open is the presence of light.3462

Remember that there are blue light receptors within the guard cells that can detect3468

light and signal the guard cells to allow the stoma to open because light is present, and this is the time when photosynthesis can occur.3476

Finally, stomata open according to a 24 hour cycle, so simply Circadian rhythm or Circadian cycle that stomata open according to a 24 hour cycle.3484

So, those are factors that would stimulate stomata to open. Factors that would stimulate stomata to close would be a lack of water.3508

The plant needs to conserve water when there is not much around, and if there is a lack of water, water cannot enter the guard cells.3518

The guard cells will not bow outward and become turgid and allow the stoma to be revealed, so lack of water.3525

The second would be increase in temperature. In high temperature, the stoma will close to minimize water loss.3532

And finally, the presence of abscisic acid, abscisic acid is a hormone-made when plants3541

are dehydrated and signals the guard cells that they should close and conserve water.3551

Finally, what is the difference between primary and secondary growth in a plant?3560

What structure is responsible for each type of growth, and what are the zones of primary growth in a root?3566

Well, primary growth is an increase in the length, and this occurs in both herbaceous and non-herbaceous or woody plants.3574

Secondary growth only occurs in non-herbaceous plants, and secondary growth is an increase in girth or width.3589

What structure is responsible for each type of growth?3600

Well, primary growth occurs in the apical meristems, and these are present at the tips of roots and shoots.3603

Secondary growth occurs in the lateral meristems, and there are a couple different types that we talked about- vascular cambium and cork cambium.3615

Finally, what are the zones of primary growth in a root?3634

We talked about several different zones in the root. The bottom zone is the zone of cell division.3639

This includes the apical meristem, and it is a region of active mitosis.3647

Just above that and overlapping it lies the zone of elongation. The newly created cells elongate and push the root further into the ground.3653

And finally, just above that, the zone of differentiation where cells become specialized in structure and function.3664

So, that was our last question and concludes this section on plant structure at Educator.com.3673

Thank you for visiting.3679

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