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Raffi Hovasapian

Raffi Hovasapian

The Biologically Active Lipids

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Table of Contents

Section 1: Preliminaries on Aqueous Chemistry
Aqueous Solutions & Concentration

39m 57s

Intro
0:00
Aqueous Solutions and Concentration
0:46
Definition of Solution
1:28
Example: Sugar Dissolved in Water
2:19
Example: Salt Dissolved in Water
3:04
A Solute Does Not Have to Be a Solid
3:37
A Solvent Does Not Have to Be a Liquid
5:02
Covalent Compounds
6:55
Ionic Compounds
7:39
Example: Table Sugar
9:12
Example: MgCl₂
10:40
Expressing Concentration: Molarity
13:42
Example 1
14:47
Example 1: Question
14:50
Example 1: Solution
15:40
Another Way to Express Concentration
22:01
Example 2
24:00
Example 2: Question
24:01
Example 2: Solution
24:49
Some Other Ways of Expressing Concentration
27:52
Example 3
29:30
Example 3: Question
29:31
Example 3: Solution
31:02
Dilution & Osmotic Pressure

38m 53s

Intro
0:00
Dilution
0:45
Definition of Dilution
0:46
Example 1: Question
2:08
Example 1: Basic Dilution Equation
4:20
Example 1: Solution
5:31
Example 2: Alternative Approach
12:05
Osmotic Pressure
14:34
Colligative Properties
15:02
Recall: Covalent Compounds and Soluble Ionic Compounds
17:24
Properties of Pure Water
19:42
Addition of a Solute
21:56
Osmotic Pressure: Conceptual Example
24:00
Equation for Osmotic Pressure
29:30
Example of 'i'
31:38
Example 3
32:50
More on Osmosis

29m 1s

Intro
0:00
More on Osmosis
1:25
Osmotic Pressure
1:26
Example 1: Molar Mass of Protein
5:25
Definition, Equation, and Unit of Osmolarity
13:13
Example 2: Osmolarity
15:19
Isotonic, Hypertonic, and Hypotonic
20:20
Example 3
22:20
More on Isotonic, Hypertonic, and Hypotonic
26:14
Osmosis vs. Osmotic Pressure
27:56
Acids & Bases

39m 11s

Intro
0:00
Acids and Bases
1:16
Let's Begin With H₂O
1:17
P-Scale
4:22
Example 1
6:39
pH
9:43
Strong Acids
11:10
Strong Bases
13:52
Weak Acids & Bases Overview
14:32
Weak Acids
15:49
Example 2: Phosphoric Acid
19:30
Weak Bases
24:50
Weak Base Produces Hydroxide Indirectly
25:41
Example 3: Pyridine
29:07
Acid Form and Base Form
32:02
Acid Reaction
35:50
Base Reaction
36:27
Ka, Kb, and Kw
37:14
Titrations and Buffers

41m 33s

Intro
0:00
Titrations
0:27
Weak Acid
0:28
Rearranging the Ka Equation
1:45
Henderson-Hasselbalch Equation
3:52
Fundamental Reaction of Acids and Bases
5:36
The Idea Behind a Titration
6:27
Let's Look at an Acetic Acid Solution
8:44
Titration Curve
17:00
Acetate
23:57
Buffers
26:57
Introduction to Buffers
26:58
What is a Buffer?
29:40
Titration Curve & Buffer Region
31:44
How a Buffer Works: Adding OH⁻
34:44
How a Buffer Works: Adding H⁺
35:58
Phosphate Buffer System
38:02
Example Problems with Acids, Bases & Buffers

44m 19s

Intro
0:00
Example 1
1:21
Example 1: Properties of Glycine
1:22
Example 1: Part A
3:40
Example 1: Part B
4:40
Example 2
9:02
Example 2: Question
9:03
Example 2: Total Phosphate Concentration
12:23
Example 2: Final Solution
17:10
Example 3
19:34
Example 3: Question
19:35
Example 3: pH Before
22:18
Example 3: pH After
24:24
Example 3: New pH
27:54
Example 4
30:00
Example 4: Question
30:01
Example 4: Equilibria
32:52
Example 4: 1st Reaction
38:04
Example 4: 2nd Reaction
39:53
Example 4: Final Solution
41:33
Hydrolysis & Condensation Reactions

18m 45s

Intro
0:00
Hydrolysis and Condensation Reactions
0:50
Hydrolysis
0:51
Condensation
2:42
Example 1: Hydrolysis of Ethyl Acetate
4:52
Example 2: Condensation of Acetic Acid with Ethanol
8:42
Example 3
11:18
Example 4: Formation & Hydrolysis of a Peptide Bond Between the Amino Acids Alanine & Serine
14:56
Section 2: Amino Acids & Proteins: Primary Structure
Amino Acids

38m 19s

Intro
0:00
Amino Acids
0:17
Proteins & Amino Acids
0:18
Difference Between Amino Acids
4:20
α-Carbon
7:08
Configuration in Biochemistry
10:43
L-Glyceraldehyde & Fischer Projection
12:32
D-Glyceraldehyde & Fischer Projection
15:31
Amino Acids in Biological Proteins are the L Enantiomer
16:50
L-Amino Acid
18:04
L-Amino Acids Correspond to S-Enantiomers in the RS System
20:10
Classification of Amino Acids
22:53
Amino Acids With Non-Polar R Groups
26:45
Glycine
27:00
Alanine
27:48
Valine
28:15
Leucine
28:58
Proline
31:08
Isoleucine
32:42
Methionine
33:43
Amino Acids With Aromatic R Groups
34:33
Phenylalanine
35:26
Tyrosine
36:02
Tryptophan
36:32
Amino Acids, Continued

27m 14s

Intro
0:00
Amino Acids With Positively Charged R Groups
0:16
Lysine
0:52
Arginine
1:55
Histidine
3:15
Amino Acids With Negatively Charged R Groups
6:28
Aspartate
6:58
Glutamate
8:11
Amino Acids With Uncharged, but Polar R Groups
8:50
Serine
8:51
Threonine
10:21
Cysteine
11:06
Asparagine
11:35
Glutamine
12:44
More on Amino Acids
14:18
Cysteine Dimerizes to Form Cystine
14:53
Tryptophan, Tyrosine, and Phenylalanine
19:07
Other Amino Acids
20:53
Other Amino Acids: Hydroxy Lysine
22:34
Other Amino Acids: r-Carboxy Glutamate
25:37
Acid/Base Behavior of Amino Acids

48m 28s

Intro
0:00
Acid/Base Behavior of Amino Acids
0:27
Acid/Base Behavior of Amino Acids
0:28
Let's Look at Alanine
1:57
Titration of Acidic Solution of Alanine with a Strong Base
2:51
Amphoteric Amino Acids
13:24
Zwitterion & Isoelectric Point
16:42
Some Amino Acids Have 3 Ionizable Groups
20:35
Example: Aspartate
24:44
Example: Tyrosine
28:50
Rule of Thumb
33:04
Basis for the Rule
35:59
Example: Describe the Degree of Protonation for Each Ionizable Group
38:46
Histidine is Special
44:58
Peptides & Proteins

45m 18s

Intro
0:00
Peptides and Proteins
0:15
Introduction to Peptides and Proteins
0:16
Formation of a Peptide Bond: The Bond Between 2 Amino Acids
1:44
Equilibrium
7:53
Example 1: Build the Following Tripeptide Ala-Tyr-Ile
9:48
Example 1: Shape Structure
15:43
Example 1: Line Structure
17:11
Peptides Bonds
20:08
Terms We'll Be Using Interchangeably
23:14
Biological Activity & Size of a Peptide
24:58
Multi-Subunit Proteins
30:08
Proteins and Prosthetic Groups
32:13
Carbonic Anhydrase
37:35
Primary, Secondary, Tertiary, and Quaternary Structure of Proteins
40:26
Amino Acid Sequencing of a Peptide Chain

42m 47s

Intro
0:00
Amino Acid Sequencing of a Peptide Chain
0:30
Amino Acid Sequence and Its Structure
0:31
Edman Degradation: Overview
2:57
Edman Degradation: Reaction - Part 1
4:58
Edman Degradation: Reaction - Part 2
10:28
Edman Degradation: Reaction - Part 3
13:51
Mechanism Step 1: PTC (Phenylthiocarbamyl) Formation
19:01
Mechanism Step 2: Ring Formation & Peptide Bond Cleavage
23:03
Example: Write Out the Edman Degradation for the Tripeptide Ala-Tyr-Ser
30:29
Step 1
30:30
Step 2
34:21
Step 3
36:56
Step 4
38:28
Step 5
39:24
Step 6
40:44
Sequencing Larger Peptides & Proteins

1h 2m 33s

Intro
0:00
Sequencing Larger Peptides and Proteins
0:28
Identifying the N-Terminal Amino Acids With the Reagent Fluorodinitrobenzene (FDNB)
0:29
Sequencing Longer Peptides & Proteins Overview
5:54
Breaking Peptide Bond: Proteases and Chemicals
8:16
Some Enzymes/Chemicals Used for Fragmentation: Trypsin
11:14
Some Enzymes/Chemicals Used for Fragmentation: Chymotrypsin
13:02
Some Enzymes/Chemicals Used for Fragmentation: Cyanogen Bromide
13:28
Some Enzymes/Chemicals Used for Fragmentation: Pepsin
13:44
Cleavage Location
14:04
Example: Chymotrypsin
16:44
Example: Pepsin
18:17
More on Sequencing Larger Peptides and Proteins
19:29
Breaking Disulfide Bonds: Performic Acid
26:08
Breaking Disulfide Bonds: Dithiothreitol Followed by Iodoacetate
31:04
Example: Sequencing Larger Peptides and Proteins
37:03
Part 1 - Breaking Disulfide Bonds, Hydrolysis and Separation
37:04
Part 2 - N-Terminal Identification
44:16
Part 3 - Sequencing Using Pepsin
46:43
Part 4 - Sequencing Using Cyanogen Bromide
52:02
Part 5 - Final Sequence
56:48
Peptide Synthesis (Merrifield Process)

49m 12s

Intro
0:00
Peptide Synthesis (Merrifield Process)
0:31
Introduction to Synthesizing Peptides
0:32
Merrifield Peptide Synthesis: General Scheme
3:03
So What Do We Do?
6:07
Synthesis of Protein in the Body Vs. The Merrifield Process
7:40
Example: Synthesis of Ala-Gly-Ser
9:21
Synthesis of Ala-Gly-Ser: Reactions Overview
11:41
Synthesis of Ala-Gly-Ser: Reaction 1
19:34
Synthesis of Ala-Gly-Ser: Reaction 2
24:34
Synthesis of Ala-Gly-Ser: Reaction 3
27:34
Synthesis of Ala-Gly-Ser: Reaction 4 & 4a
28:48
Synthesis of Ala-Gly-Ser: Reaction 5
33:38
Synthesis of Ala-Gly-Ser: Reaction 6
36:45
Synthesis of Ala-Gly-Ser: Reaction 7 & 7a
37:44
Synthesis of Ala-Gly-Ser: Reaction 8
39:47
Synthesis of Ala-Gly-Ser: Reaction 9 & 10
43:23
Chromatography: Eluent, Stationary Phase, and Eluate
45:55
More Examples with Amino Acids & Peptides

54m 31s

Intro
0:00
Example 1
0:22
Data
0:23
Part A: What is the pI of Serine & Draw the Correct Structure
2:11
Part B: How Many mL of NaOH Solution Have Been Added at This Point (pI)?
5:27
Part C: At What pH is the Average Charge on Serine
10:50
Part D: Draw the Titration Curve for This Situation
14:50
Part E: The 10 mL of NaOH Added to the Solution at the pI is How Many Equivalents?
17:35
Part F: Serine Buffer Solution
20:22
Example 2
23:04
Data
23:05
Part A: Calculate the Minimum Molar Mass of the Protein
25:12
Part B: How Many Tyr Residues in this Protein?
28:34
Example 3
30:08
Question
30:09
Solution
34:30
Example 4
48:46
Question
48:47
Solution
49:50
Section 3: Proteins: Secondary, Tertiary, and Quaternary Structure
Alpha Helix & Beta Conformation

50m 52s

Intro
0:00
Alpha Helix and Beta Conformation
0:28
Protein Structure Overview
0:29
Weak interactions Among the Amino Acid in the Peptide Chain
2:11
Two Principals of Folding Patterns
4:56
Peptide Bond
7:00
Peptide Bond: Resonance
9:46
Peptide Bond: φ Bond & ψ Bond
11:22
Secondary Structure
15:08
α-Helix Folding Pattern
17:28
Illustration 1: α-Helix Folding Pattern
19:22
Illustration 2: α-Helix Folding Pattern
21:39
β-Sheet
25:16
β-Conformation
26:04
Parallel & Anti-parallel
28:44
Parallel β-Conformation Arrangement of the Peptide Chain
30:12
Putting Together a Parallel Peptide Chain
35:16
Anti-Parallel β-Conformation Arrangement
37:42
Tertiary Structure
45:03
Quaternary Structure
45:52
Illustration 3: Myoglobin Tertiary Structure & Hemoglobin Quaternary Structure
47:13
Final Words on Alpha Helix and Beta Conformation
48:34
Section 4: Proteins: Function
Protein Function I: Ligand Binding & Myoglobin

51m 36s

Intro
0:00
Protein Function I: Ligand Binding & Myoglobin
0:30
Ligand
1:02
Binding Site
2:06
Proteins are Not Static or Fixed
3:36
Multi-Subunit Proteins
5:46
O₂ as a Ligand
7:21
Myoglobin, Protoporphyrin IX, Fe ²⁺, and O₂
12:54
Protoporphyrin Illustration
14:25
Myoglobin With a Heme Group Illustration
17:02
Fe²⁺ has 6 Coordination Sites & Binds O₂
18:10
Heme
19:44
Myoglobin Overview
22:40
Myoglobin and O₂ Interaction
23:34
Keq or Ka & The Measure of Protein's Affinity for Its Ligand
26:46
Defining α: Fraction of Binding Sites Occupied
32:52
Graph: α vs. [L]
37:33
For The Special Case of α = 0.5
39:01
Association Constant & Dissociation Constant
43:54
α & Kd
45:15
Myoglobin's Binding of O₂
48:20
Protein Function II: Hemoglobin

1h 3m 36s

Intro
0:00
Protein Function II: Hemoglobin
0:14
Hemoglobin Overview
0:15
Hemoglobin & Its 4 Subunits
1:22
α and β Interactions
5:18
Two Major Conformations of Hb: T State (Tense) & R State (Relaxed)
8:06
Transition From The T State to R State
12:03
Binding of Hemoglobins & O₂
14:02
Binding Curve
18:32
Hemoglobin in the Lung
27:28
Signoid Curve
30:13
Cooperative Binding
32:25
Hemoglobin is an Allosteric Protein
34:26
Homotropic Allostery
36:18
Describing Cooperative Binding Quantitatively
38:06
Deriving The Hill Equation
41:52
Graphing the Hill Equation
44:43
The Slope and Degree of Cooperation
46:25
The Hill Coefficient
49:48
Hill Coefficient = 1
51:08
Hill Coefficient < 1
55:55
Where the Graph Hits the x-axis
56:11
Graph for Hemoglobin
58:02
Protein Function III: More on Hemoglobin

1h 7m 16s

Intro
0:00
Protein Function III: More on Hemoglobin
0:11
Two Models for Cooperative Binding: MWC & Sequential Model
0:12
MWC Model
1:31
Hemoglobin Subunits
3:32
Sequential Model
8:00
Hemoglobin Transports H⁺ & CO₂
17:23
Binding Sites of H⁺ and CO₂
19:36
CO₂ is Converted to Bicarbonate
23:28
Production of H⁺ & CO₂ in Tissues
27:28
H⁺ & CO₂ Binding are Inversely Related to O₂ Binding
28:31
The H⁺ Bohr Effect: His¹⁴⁶ Residue on the β Subunits
33:31
Heterotropic Allosteric Regulation of O₂ Binding by 2,3-Biphosphoglycerate (2,3 BPG)
39:53
Binding Curve for 2,3 BPG
56:21
Section 5: Enzymes
Enzymes I

41m 38s

Intro
0:00
Enzymes I
0:38
Enzymes Overview
0:39
Cofactor
4:38
Holoenzyme
5:52
Apoenzyme
6:40
Riboflavin, FAD, Pyridoxine, Pyridoxal Phosphate Structures
7:28
Carbonic Anhydrase
8:45
Classification of Enzymes
9:55
Example: EC 1.1.1.1
13:04
Reaction of Oxidoreductases
16:23
Enzymes: Catalysts, Active Site, and Substrate
18:28
Illustration of Enzymes, Substrate, and Active Site
27:22
Catalysts & Activation Energies
29:57
Intermediates
36:00
Enzymes II

44m 2s

Intro
0:00
Enzymes II: Transitions State, Binding Energy, & Induced Fit
0:18
Enzymes 'Fitting' Well With The Transition State
0:20
Example Reaction: Breaking of a Stick
3:40
Another Energy Diagram
8:20
Binding Energy
9:48
Enzymes Specificity
11:03
Key Point: Optimal Interactions Between Substrate & Enzymes
15:15
Induced Fit
16:25
Illustrations: Induced Fit
20:58
Enzymes II: Catalytic Mechanisms
22:17
General Acid/Base Catalysis
23:56
Acid Form & Base Form of Amino Acid: Glu &Asp
25:26
Acid Form & Base Form of Amino Acid: Lys & Arg
26:30
Acid Form & Base Form of Amino Acid: Cys
26:51
Acid Form & Base Form of Amino Acid: His
27:30
Acid Form & Base Form of Amino Acid: Ser
28:16
Acid Form & Base Form of Amino Acid: Tyr
28:30
Example: Phosphohexose Isomerase
29:20
Covalent Catalysis
34:19
Example: Glyceraldehyde 3-Phosphate Dehydrogenase
35:34
Metal Ion Catalysis: Isocitrate Dehydrogenase
38:45
Function of Mn²⁺
42:15
Enzymes III: Kinetics

56m 40s

Intro
0:00
Enzymes III: Kinetics
1:40
Rate of an Enzyme-Catalyzed Reaction & Substrate Concentration
1:41
Graph: Substrate Concentration vs. Reaction Rate
10:43
Rate At Low and High Substrate Concentration
14:26
Michaelis & Menten Kinetics
20:16
More On Rate & Concentration of Substrate
22:46
Steady-State Assumption
26:02
Rate is Determined by How Fast ES Breaks Down to Product
31:36
Total Enzyme Concentration: [Et] = [E] + [ES]
35:35
Rate of ES Formation
36:44
Rate of ES Breakdown
38:40
Measuring Concentration of Enzyme-Substrate Complex
41:19
Measuring Initial & Maximum Velocity
43:43
Michaelis & Menten Equation
46:44
What Happens When V₀ = (1/2) Vmax?
49:12
When [S] << Km
53:32
When [S] >> Km
54:44
Enzymes IV: Lineweaver-Burk Plots

20m 37s

Intro
0:00
Enzymes IV: Lineweaver-Burk Plots
0:45
Deriving The Lineweaver-Burk Equation
0:46
Lineweaver-Burk Plots
3:55
Example 1: Carboxypeptidase A
8:00
More on Km, Vmax, and Enzyme-catalyzed Reaction
15:54
Enzymes V: Enzyme Inhibition

51m 37s

Intro
0:00
Enzymes V: Enzyme Inhibition Overview
0:42
Enzyme Inhibitors Overview
0:43
Classes of Inhibitors
2:32
Competitive Inhibition
3:08
Competitive Inhibition
3:09
Michaelis & Menten Equation in the Presence of a Competitive Inhibitor
7:40
Double-Reciprocal Version of the Michaelis & Menten Equation
14:48
Competitive Inhibition Graph
16:37
Uncompetitive Inhibition
19:23
Uncompetitive Inhibitor
19:24
Michaelis & Menten Equation for Uncompetitive Inhibition
22:10
The Lineweaver-Burk Equation for Uncompetitive Inhibition
26:04
Uncompetitive Inhibition Graph
27:42
Mixed Inhibition
30:30
Mixed Inhibitor
30:31
Double-Reciprocal Version of the Equation
33:34
The Lineweaver-Burk Plots for Mixed Inhibition
35:02
Summary of Reversible Inhibitor Behavior
38:00
Summary of Reversible Inhibitor Behavior
38:01
Note: Non-Competitive Inhibition
42:22
Irreversible Inhibition
45:15
Irreversible Inhibition
45:16
Penicillin & Transpeptidase Enzyme
46:50
Enzymes VI: Regulatory Enzymes

51m 23s

Intro
0:00
Enzymes VI: Regulatory Enzymes
0:45
Regulatory Enzymes Overview
0:46
Example: Glycolysis
2:27
Allosteric Regulatory Enzyme
9:19
Covalent Modification
13:08
Two Other Regulatory Processes
16:28
Allosteric Regulation
20:58
Feedback Inhibition
25:12
Feedback Inhibition Example: L-Threonine → L-Isoleucine
26:03
Covalent Modification
27:26
Covalent Modulators: -PO₃²⁻
29:30
Protein Kinases
31:59
Protein Phosphatases
32:47
Addition/Removal of -PO₃²⁻ and the Effect on Regulatory Enzyme
33:36
Phosphorylation Sites of a Regulatory Enzyme
38:38
Proteolytic Cleavage
41:48
Zymogens: Chymotrypsin & Trypsin
43:58
Enzymes That Use More Than One Regulatory Process: Bacterial Glutamine Synthetase
48:59
Why The Complexity?
50:27
Enzymes VII: Km & Kcat

54m 49s

Intro
0:00
Km
1:48
Recall the Michaelis–Menten Equation
1:49
Km & Enzyme's Affinity
6:18
Rate Forward, Rate Backward, and Equilibrium Constant
11:08
When an Enzyme's Affinity for Its Substrate is High
14:17
More on Km & Enzyme Affinity
17:29
The Measure of Km Under Michaelis–Menten kinetic
23:19
Kcat (First-order Rate Constant or Catalytic Rate Constant)
24:10
Kcat: Definition
24:11
Kcat & The Michaelis–Menten Postulate
25:18
Finding Vmax and [Et}
27:27
Units for Vmax and Kcat
28:26
Kcat: Turnover Number
28:55
Michaelis–Menten Equation
32:12
Km & Kcat
36:37
Second Order Rate Equation
36:38
(Kcat)/(Km): Overview
39:22
High (Kcat)/(Km)
40:20
Low (Kcat)/(Km)
43:16
Practical Big Picture
46:28
Upper Limit to (Kcat)/(Km)
48:56
More On Kcat and Km
49:26
Section 6: Carbohydrates
Monosaccharides

1h 17m 46s

Intro
0:00
Monosaccharides
1:49
Carbohydrates Overview
1:50
Three Major Classes of Carbohydrates
4:48
Definition of Monosaccharides
5:46
Examples of Monosaccharides: Aldoses
7:06
D-Glyceraldehyde
7:39
D-Erythrose
9:00
D-Ribose
10:10
D-Glucose
11:20
Observation: Aldehyde Group
11:54
Observation: Carbonyl 'C'
12:30
Observation: D & L Naming System
12:54
Examples of Monosaccharides: Ketose
16:54
Dihydroxy Acetone
17:28
D-Erythrulose
18:30
D-Ribulose
19:49
D-Fructose
21:10
D-Glucose Comparison
23:18
More information of Ketoses
24:50
Let's Look Closer at D-Glucoses
25:50
Let's Look At All the D-Hexose Stereoisomers
31:22
D-Allose
32:20
D-Altrose
33:01
D-Glucose
33:39
D-Gulose
35:00
D-Mannose
35:40
D-Idose
36:42
D-Galactose
37:14
D-Talose
37:42
Epimer
40:05
Definition of Epimer
40:06
Example of Epimer: D-Glucose, D-Mannose, and D-Galactose
40:57
Hemiacetal or Hemiketal
44:36
Hemiacetal/Hemiketal Overview
45:00
Ring Formation of the α and β Configurations of D-Glucose
50:52
Ring Formation of the α and β Configurations of Fructose
1:01:39
Haworth Projection
1:07:34
Pyranose & Furanose Overview
1:07:38
Haworth Projection: Pyranoses
1:09:30
Haworth Projection: Furanose
1:14:56
Hexose Derivatives & Reducing Sugars

37m 6s

Intro
0:00
Hexose Derivatives
0:15
Point of Clarification: Forming a Cyclic Sugar From a Linear Sugar
0:16
Let's Recall the α and β Anomers of Glucose
8:42
α-Glucose
10:54
Hexose Derivatives that Play Key Roles in Physiology Progression
17:38
β-Glucose
18:24
β-Glucosamine
18:48
N-Acetyl-β-Glucosamine
20:14
β-Glucose-6-Phosphate
22:22
D-Gluconate
24:10
Glucono-δ-Lactone
26:33
Reducing Sugars
29:50
Reducing Sugars Overview
29:51
Reducing Sugars Example: β-Galactose
32:36
Disaccharides

43m 32s

Intro
0:00
Disaccharides
0:15
Disaccharides Overview
0:19
Examples of Disaccharides & How to Name Them
2:49
Disaccharides Trehalose Overview
15:46
Disaccharides Trehalose: Flip
20:52
Disaccharides Trehalose: Spin
28:36
Example: Draw the Structure
33:12
Polysaccharides

39m 25s

Intro
0:00
Recap Example: Draw the Structure of Gal(α1↔β1)Man
0:38
Polysaccharides
9:46
Polysaccharides Overview
9:50
Homopolysaccharide
13:12
Heteropolysaccharide
13:47
Homopolysaccharide as Fuel Storage
16:23
Starch Has Two Types of Glucose Polymer: Amylose
17:10
Starch Has Two Types of Glucose Polymer: Amylopectin
18:04
Polysaccharides: Reducing End & Non-Reducing End
19:30
Glycogen
20:06
Examples: Structures of Polysaccharides
21:42
Let's Draw an (α1→4) & (α1→6) of Amylopectin by Hand.
28:14
More on Glycogen
31:17
Glycogen, Concentration, & The Concept of Osmolarity
35:16
Polysaccharides, Part 2

44m 15s

Intro
0:00
Polysaccharides
0:17
Example: Cellulose
0:34
Glycoside Bond
7:25
Example Illustrations
12:30
Glycosaminoglycans Part 1
15:55
Glycosaminoglycans Part 2
18:34
Glycosaminoglycans & Sulfate Attachments
22:42
β-D-N-Acetylglucosamine
24:49
β-D-N-AcetylGalactosamine
25:42
β-D-Glucuronate
26:44
β-L-Iduronate
27:54
More on Sulfate Attachments
29:49
Hylarunic Acid
32:00
Hyaluronates
39:32
Other Glycosaminoglycans
40:46
Glycoconjugates

44m 23s

Intro
0:00
Glycoconjugates
0:24
Overview
0:25
Proteoglycan
2:53
Glycoprotein
5:20
Glycolipid
7:25
Proteoglycan vs. Glycoprotein
8:15
Cell Surface Diagram
11:17
Proteoglycan Common Structure
14:24
Example: Chondroitin-4-Sulfate
15:06
Glycoproteins
19:50
The Monomers that Commonly Show Up in The Oligo Portions of Glycoproteins
28:02
N-Acetylneuraminic Acid
31:17
L-Furose
32:37
Example of an N-Linked Oligosaccharide
33:21
Cell Membrane Structure
36:35
Glycolipids & Lipopolysaccharide
37:22
Structure Example
41:28
More Example Problems with Carbohydrates

40m 22s

Intro
0:00
Example 1
1:09
Example 2
2:34
Example 3
5:12
Example 4
16:19
Question
16:20
Solution
17:25
Example 5
24:18
Question
24:19
Structure of 2,3-Di-O-Methylglucose
26:47
Part A
28:11
Part B
33:46
Section 7: Lipids
Fatty Acids & Triacylglycerols

54m 55s

Intro
0:00
Fatty Acids
0:32
Lipids Overview
0:34
Introduction to Fatty Acid
3:18
Saturated Fatty Acid
6:13
Unsaturated or Polyunsaturated Fatty Acid
7:07
Saturated Fatty Acid Example
7:46
Unsaturated Fatty Acid Example
9:06
Notation Example: Chain Length, Degree of Unsaturation, & Double Bonds Location of Fatty Acid
11:56
Example 1: Draw the Structure
16:18
Example 2: Give the Shorthand for cis,cis-5,8-Hexadecadienoic Acid
20:12
Example 3
23:12
Solubility of Fatty Acids
25:45
Melting Points of Fatty Acids
29:40
Triacylglycerols
34:13
Definition of Triacylglycerols
34:14
Structure of Triacylglycerols
35:08
Example: Triacylglycerols
40:23
Recall Ester Formation
43:57
The Body's Primary Fuel-Reserves
47:22
Two Primary Advantages to Storing Energy as Triacylglycerols Instead of Glycogen: Number 1
49:24
Two Primary Advantages to Storing Energy as Triacylglycerols Instead of Glycogen: Number 2
51:54
Membrane Lipids

38m 51s

Intro
0:00
Membrane Lipids
0:26
Definition of Membrane Lipids
0:27
Five Major Classes of Membrane Lipids
2:38
Glycerophospholipids
5:04
Glycerophospholipids Overview
5:05
The X Group
8:05
Example: Phosphatidyl Ethanolamine
10:51
Example: Phosphatidyl Choline
13:34
Phosphatidyl Serine
15:16
Head Groups
16:50
Ether Linkages Instead of Ester Linkages
20:05
Galactolipids
23:39
Galactolipids Overview
23:40
Monogalactosyldiacylglycerol: MGDG
25:17
Digalactosyldiacylglycerol: DGDG
28:13
Structure Examples 1: Lipid Bilayer
31:35
Structure Examples 2: Cross Section of a Cell
34:56
Structure Examples 3: MGDG & DGDG
36:28
Membrane Lipids, Part 2

38m 20s

Intro
0:00
Sphingolipids
0:11
Sphingolipid Overview
0:12
Sphingosine Structure
1:42
Ceramide
3:56
Subclasses of Sphingolipids Overview
6:00
Subclasses of Sphingolipids: Sphingomyelins
7:53
Sphingomyelins
7:54
Subclasses of Sphingolipids: Glycosphingolipid
12:47
Glycosphingolipid Overview
12:48
Cerebrosides & Globosides Overview
14:33
Example: Cerebrosides
15:43
Example: Globosides
17:14
Subclasses of Sphingolipids: Gangliosides
19:07
Gangliosides
19:08
Medical Application: Tay-Sachs Disease
23:34
Sterols
30:45
Sterols: Basic Structure
30:46
Important Example: Cholesterol
32:01
Structures Example
34:13
The Biologically Active Lipids

48m 36s

Intro
0:00
The Biologically Active Lipids
0:44
Phosphatidyl Inositol Structure
0:45
Phosphatidyl Inositol Reaction
3:24
Image Example
12:49
Eicosanoids
14:12
Arachidonic Acid & Membrane Lipid Containing Arachidonic Acid
18:41
Three Classes of Eicosanoids
20:42
Overall Structures
21:38
Prostagladins
22:56
Thromboxane
27:19
Leukotrienes
30:19
More On The Biologically Active Lipids
33:34
Steroid Hormones
33:35
Fat Soluble Vitamins
38:25
Vitamin D₃
40:40
Vitamin A
43:17
Vitamin E
45:12
Vitamin K
47:17
Section 8: Energy & Biological Systems (Bioenergetics)
Thermodynamics, Free Energy & Equilibrium

45m 51s

Intro
0:00
Thermodynamics, Free Energy and Equilibrium
1:03
Reaction: Glucose + Pi → Glucose 6-Phosphate
1:50
Thermodynamics & Spontaneous Processes
3:31
In Going From Reactants → Product, a Reaction Wants to Release Heat
6:30
A Reaction Wants to Become More Disordered
9:10
∆H < 0
10:30
∆H > 0
10:57
∆S > 0
11:23
∆S <0
11:56
∆G = ∆H - T∆S at Constant Pressure
12:15
Gibbs Free Energy
15:00
∆G < 0
16:49
∆G > 0
17:07
Reference Frame For Thermodynamics Measurements
17:57
More On BioChemistry Standard
22:36
Spontaneity
25:36
Keq
31:45
Example: Glucose + Pi → Glucose 6-Phosphate
34:14
Example Problem 1
40:25
Question
40:26
Solution
41:12
More on Thermodynamics & Free Energy

37m 6s

Intro
0:00
More on Thermodynamics & Free Energy
0:16
Calculating ∆G Under Standard Conditions
0:17
Calculating ∆G Under Physiological Conditions
2:05
∆G < 0
5:39
∆G = 0
7:03
Reaction Moving Forward Spontaneously
8:00
∆G & The Maximum Theoretical Amount of Free Energy Available
10:36
Example Problem 1
13:11
Reactions That Have Species in Common
17:48
Example Problem 2: Part 1
20:10
Example Problem 2: Part 2- Enzyme Hexokinase & Coupling
25:08
Example Problem 2: Part 3
30:34
Recap
34:45
ATP & Other High-Energy Compounds

44m 32s

Intro
0:00
ATP & Other High-Energy Compounds
0:10
Endergonic Reaction Coupled With Exergonic Reaction
0:11
Major Theme In Metabolism
6:56
Why the ∆G°' for ATP Hydrolysis is Large & Negative
12:24
∆G°' for ATP Hydrolysis
12:25
Reason 1: Electrostatic Repulsion
14:24
Reason 2: Pi & Resonance Forms
15:33
Reason 3: Concentrations of ADP & Pi
17:32
ATP & Other High-Energy Compounds Cont'd
18:48
More On ∆G°' & Hydrolysis
18:49
Other Compounds That Have Large Negative ∆G°' of Hydrolysis: Phosphoenol Pyruvate (PEP)
25:14
Enzyme Pyruvate Kinase
30:36
Another High Energy Molecule: 1,3 Biphosphoglycerate
36:17
Another High Energy Molecule: Phophocreatine
39:41
Phosphoryl Group Transfers

30m 8s

Intro
0:00
Phosphoryl Group Transfer
0:27
Phosphoryl Group Transfer Overview
0:28
Example: Glutamate → Glutamine Part 1
7:11
Example: Glutamate → Glutamine Part 2
13:29
ATP Not Only Transfers Phosphoryl, But Also Pyrophosphoryl & Adenylyl Groups
17:03
Attack At The γ Phosphorous Transfers a Phosphoryl
19:02
Attack At The β Phosphorous Gives Pyrophosphoryl
22:44
Oxidation-Reduction Reactions

49m 46s

Intro
0:00
Oxidation-Reduction Reactions
1:32
Redox Reactions
1:33
Example 1: Mg + Al³⁺ → Mg²⁺ + Al
3:49
Reduction Potential Definition
10:47
Reduction Potential Example
13:38
Organic Example
22:23
Review: How To Find The Oxidation States For Carbon
24:15
Examples: Oxidation States For Carbon
27:45
Example 1: Oxidation States For Carbon
27:46
Example 2: Oxidation States For Carbon
28:36
Example 3: Oxidation States For Carbon
29:18
Example 4: Oxidation States For Carbon
29:44
Example 5: Oxidation States For Carbon
30:10
Example 6: Oxidation States For Carbon
30:40
Example 7: Oxidation States For Carbon
31:20
Example 8: Oxidation States For Carbon
32:10
Example 9: Oxidation States For Carbon
32:52
Oxidation-Reduction Reactions, cont'd
35:22
More On Reduction Potential
35:28
Lets' Start With ∆G = ∆G°' + RTlnQ
38:29
Example: Oxidation Reduction Reactions
41:42
More On Oxidation-Reduction Reactions

56m 34s

Intro
0:00
More On Oxidation-Reduction Reactions
0:10
Example 1: What If the Concentrations Are Not Standard?
0:11
Alternate Procedure That Uses The 1/2 Reactions Individually
8:57
Universal Electron Carriers in Aqueous Medium: NAD+ & NADH
15:12
The Others Are…
19:22
NAD+ & NADP Coenzymes
20:56
FMN & FAD
22:03
Nicotinamide Adenine Dinucleotide (Phosphate)
23:03
Reduction 1/2 Reactions
36:10
Ratio of NAD+ : NADH
36:52
Ratio of NADPH : NADP+
38:02
Specialized Roles of NAD+ & NADPH
38:48
Oxidoreductase Enzyme Overview
40:26
Examples of Oxidoreductase
43:32
The Flavin Nucleotides
46:46
Example Problems For Bioenergetics

42m 12s

Intro
0:00
Example 1: Calculate the ∆G°' For The Following Reaction
1:04
Example 1: Question
1:05
Example 1: Solution
2:20
Example 2: Calculate the Keq For the Following
4:20
Example 2: Question
4:21
Example 2: Solution
5:54
Example 3: Calculate the ∆G°' For The Hydrolysis of ATP At 25°C
8:52
Example 3: Question
8:53
Example 3: Solution
10:30
Example 3: Alternate Procedure
13:48
Example 4: Problems For Bioenergetics
16:46
Example 4: Questions
16:47
Example 4: Part A Solution
21:19
Example 4: Part B Solution
23:26
Example 4: Part C Solution
26:12
Example 5: Problems For Bioenergetics
29:27
Example 5: Questions
29:35
Example 5: Solution - Part 1
32:16
Example 5: Solution - Part 2
34:39
Section 9: Glycolysis and Gluconeogenesis
Overview of Glycolysis I

43m 32s

Intro
0:00
Overview of Glycolysis
0:48
Three Primary Paths For Glucose
1:04
Preparatory Phase of Glycolysis
4:40
Payoff Phase of Glycolysis
6:40
Glycolysis Reactions Diagram
7:58
Enzymes of Glycolysis
12:41
Glycolysis Reactions
16:02
Step 1
16:03
Step 2
18:03
Step 3
18:52
Step 4
20:08
Step 5
21:42
Step 6
22:44
Step 7
24:22
Step 8
25:11
Step 9
26:00
Step 10
26:51
Overview of Glycolysis Cont.
27:28
The Overall Reaction for Glycolysis
27:29
Recall The High-Energy Phosphorylated Compounds Discusses In The Bioenergetics Unit
33:10
What Happens To The Pyruvate That Is Formed?
37:58
Glycolysis II

1h 1m 47s

Intro
0:00
Glycolysis Step 1: The Phosphorylation of Glucose
0:27
Glycolysis Step 1: Reaction
0:28
Hexokinase
2:28
Glycolysis Step 1: Mechanism-Simple Nucleophilic Substitution
6:34
Glycolysis Step 2: Conversion of Glucose 6-Phosphate → Fructose 6-Phosphate
11:33
Glycolysis Step 2: Reaction
11:34
Glycolysis Step 2: Mechanism, Part 1
14:40
Glycolysis Step 2: Mechanism, Part 2
18:16
Glycolysis Step 2: Mechanism, Part 3
19:56
Glycolysis Step 2: Mechanism, Part 4 (Ring Closing & Dissociation)
21:54
Glycolysis Step 3: Conversion of Fructose 6-Phosphate to Fructose 1,6-Biphosphate
24:16
Glycolysis Step 3: Reaction
24:17
Glycolysis Step 3: Mechanism
26:40
Glycolysis Step 4: Cleavage of Fructose 1,6-Biphosphate
31:10
Glycolysis Step 4: Reaction
31:11
Glycolysis Step 4: Mechanism, Part 1 (Binding & Ring Opening)
35:26
Glycolysis Step 4: Mechanism, Part 2
37:40
Glycolysis Step 4: Mechanism, Part 3
39:30
Glycolysis Step 4: Mechanism, Part 4
44:00
Glycolysis Step 4: Mechanism, Part 5
46:34
Glycolysis Step 4: Mechanism, Part 6
49:00
Glycolysis Step 4: Mechanism, Part 7
50:12
Hydrolysis of The Imine
52:33
Glycolysis Step 5: Conversion of Dihydroxyaceton Phosphate to Glyceraldehyde 3-Phosphate
55:38
Glycolysis Step 5: Reaction
55:39
Breakdown and Numbering of Sugar
57:40
Glycolysis III

59m 17s

Intro
0:00
Glycolysis Step 5: Conversion of Dihydroxyaceton Phosphate to Glyceraldehyde 3-Phosphate
0:44
Glycolysis Step 5: Mechanism, Part 1
0:45
Glycolysis Step 5: Mechanism, Part 2
3:53
Glycolysis Step 6: Oxidation of Glyceraldehyde 3-Phosphate to 1,3-Biphosphoglycerate
5:14
Glycolysis Step 6: Reaction
5:15
Glycolysis Step 6: Mechanism, Part 1
8:52
Glycolysis Step 6: Mechanism, Part 2
12:58
Glycolysis Step 6: Mechanism, Part 3
14:26
Glycolysis Step 6: Mechanism, Part 4
16:23
Glycolysis Step 7: Phosphoryl Transfer From 1,3-Biphosphoglycerate to ADP to Form ATP
19:08
Glycolysis Step 7: Reaction
19:09
Substrate-Level Phosphorylation
23:18
Glycolysis Step 7: Mechanism (Nucleophilic Substitution)
26:57
Glycolysis Step 8: Conversion of 3-Phosphoglycerate to 2-Phosphoglycerate
28:44
Glycolysis Step 8: Reaction
28:45
Glycolysis Step 8: Mechanism, Part 1
30:08
Glycolysis Step 8: Mechanism, Part 2
32:24
Glycolysis Step 8: Mechanism, Part 3
34:02
Catalytic Cycle
35:42
Glycolysis Step 9: Dehydration of 2-Phosphoglycerate to Phosphoenol Pyruvate
37:20
Glycolysis Step 9: Reaction
37:21
Glycolysis Step 9: Mechanism, Part 1
40:12
Glycolysis Step 9: Mechanism, Part 2
42:01
Glycolysis Step 9: Mechanism, Part 3
43:58
Glycolysis Step 10: Transfer of a Phosphoryl Group From Phosphoenol Pyruvate To ADP To Form ATP
45:16
Glycolysis Step 10: Reaction
45:17
Substrate-Level Phosphorylation
48:32
Energy Coupling Reaction
51:24
Glycolysis Balance Sheet
54:15
Glycolysis Balance Sheet
54:16
What Happens to The 6 Carbons of Glucose?
56:22
What Happens to 2 ADP & 2 Pi?
57:04
What Happens to The 4e⁻ ?
57:15
Glycolysis IV

39m 47s

Intro
0:00
Feeder Pathways
0:42
Feeder Pathways Overview
0:43
Starch, Glycogen
2:25
Lactose
4:38
Galactose
4:58
Manose
5:22
Trehalose
5:45
Sucrose
5:56
Fructose
6:07
Fates of Pyruvate: Aerobic & Anaerobic Conditions
7:39
Aerobic Conditions & Pyruvate
7:40
Anaerobic Fates of Pyruvate
11:18
Fates of Pyruvate: Lactate Acid Fermentation
14:10
Lactate Acid Fermentation
14:11
Fates of Pyruvate: Ethanol Fermentation
19:01
Ethanol Fermentation Reaction
19:02
TPP: Thiamine Pyrophosphate (Functions and Structure)
23:10
Ethanol Fermentation Mechanism, Part 1
27:53
Ethanol Fermentation Mechanism, Part 2
29:06
Ethanol Fermentation Mechanism, Part 3
31:15
Ethanol Fermentation Mechanism, Part 4
32:44
Ethanol Fermentation Mechanism, Part 5
34:33
Ethanol Fermentation Mechanism, Part 6
35:48
Gluconeogenesis I

41m 34s

Intro
0:00
Gluconeogenesis, Part 1
1:02
Gluconeogenesis Overview
1:03
3 Glycolytic Reactions That Are Irreversible Under Physiological Conditions
2:29
Gluconeogenesis Reactions Overview
6:17
Reaction: Pyruvate to Oxaloacetate
11:07
Reaction: Oxaloacetate to Phosphoenolpyruvate (PEP)
13:29
First Pathway That Pyruvate Can Take to Become Phosphoenolpyruvate
15:24
Second Pathway That Pyruvate Can Take to Become Phosphoenolpyruvate
21:00
Transportation of Pyruvate From The Cytosol to The Mitochondria
24:15
Transportation Mechanism, Part 1
26:41
Transportation Mechanism, Part 2
30:43
Transportation Mechanism, Part 3
34:04
Transportation Mechanism, Part 4
38:14
Gluconeogenesis II

34m 18s

Intro
0:00
Oxaloacetate → Phosphoenolpyruvate (PEP)
0:35
Mitochondrial Membrane Does Not Have a Transporter for Oxaloactate
0:36
Reaction: Oxaloacetate to Phosphoenolpyruvate (PEP)
3:36
Mechanism: Oxaloacetate to Phosphoenolpyruvate (PEP)
4:48
Overall Reaction: Pyruvate to Phosphoenolpyruvate
7:01
Recall The Two Pathways That Pyruvate Can Take to Become Phosphoenolpyruvate
10:16
NADH in Gluconeogenesis
12:29
Second Pathway: Lactate → Pyruvate
18:22
Cytosolic PEP Carboxykinase, Mitochondrial PEP Carboxykinase, & Isozymes
18:23
2nd Bypass Reaction
23:04
3rd Bypass Reaction
24:01
Overall Process
25:17
Other Feeder Pathways For Gluconeogenesis
26:35
Carbon Intermediates of The Citric Acid Cycle
26:36
Amino Acids & The Gluconeogenic Pathway
29:45
Glycolysis & Gluconeogenesis Are Reciprocally Regulated
32:00
The Pentose Phosphate Pathway

42m 52s

Intro
0:00
The Pentose Phosphate Pathway Overview
0:17
The Major Fate of Glucose-6-Phosphate
0:18
The Pentose Phosphate Pathway (PPP) Overview
1:00
Oxidative Phase of The Pentose Phosphate Pathway
4:33
Oxidative Phase of The Pentose Phosphate Pathway: Reaction Overview
4:34
Ribose-5-Phosphate: Glutathione & Reductive Biosynthesis
9:02
Glucose-6-Phosphate to 6-Phosphogluconate
12:48
6-Phosphogluconate to Ribulose-5-Phosphate
15:39
Ribulose-5-Phosphate to Ribose-5-Phosphate
17:05
Non-Oxidative Phase of The Pentose Phosphate Pathway
19:55
Non-Oxidative Phase of The Pentose Phosphate Pathway: Overview
19:56
General Transketolase Reaction
29:03
Transaldolase Reaction
35:10
Final Transketolase Reaction
39:10
Section 10: The Citric Acid Cycle (Krebs Cycle)
Citric Acid Cycle I

36m 10s

Intro
0:00
Stages of Cellular Respiration
0:23
Stages of Cellular Respiration
0:24
From Pyruvate to Acetyl-CoA
6:56
From Pyruvate to Acetyl-CoA: Pyruvate Dehydrogenase Complex
6:57
Overall Reaction
8:42
Oxidative Decarboxylation
11:54
Pyruvate Dehydrogenase (PDH) & Enzymes
15:30
Pyruvate Dehydrogenase (PDH) Requires 5 Coenzymes
17:15
Molecule of CoEnzyme A
18:52
Thioesters
20:56
Lipoic Acid
22:31
Lipoate Is Attached To a Lysine Residue On E₂
24:42
Pyruvate Dehydrogenase Complex: Reactions
26:36
E1: Reaction 1 & 2
30:38
E2: Reaction 3
31:58
E3: Reaction 4 & 5
32:44
Substrate Channeling
34:17
Citric Acid Cycle II

49m 20s

Intro
0:00
Citric Acid Cycle Reactions Overview
0:26
Citric Acid Cycle Reactions Overview: Part 1
0:27
Citric Acid Cycle Reactions Overview: Part 2
7:03
Things to Note
10:58
Citric Acid Cycle Reactions & Mechanism
13:57
Reaction 1: Formation of Citrate
13:58
Reaction 1: Mechanism
19:01
Reaction 2: Citrate to Cis Aconistate to Isocitrate
28:50
Reaction 3: Isocitrate to α-Ketoglutarate
32:35
Reaction 3: Two Isocitrate Dehydrogenase Enzymes
36:24
Reaction 3: Mechanism
37:33
Reaction 4: Oxidation of α-Ketoglutarate to Succinyl-CoA
41:38
Reaction 4: Notes
46:34
Citric Acid Cycle III

44m 11s

Intro
0:00
Citric Acid Cycle Reactions & Mechanism
0:21
Reaction 5: Succinyl-CoA to Succinate
0:24
Reaction 5: Reaction Sequence
2:35
Reaction 6: Oxidation of Succinate to Fumarate
8:28
Reaction 7: Fumarate to Malate
10:17
Reaction 8: Oxidation of L-Malate to Oxaloacetate
14:15
More On The Citric Acid Cycle
17:17
Energy from Oxidation
17:18
How Can We Transfer This NADH Into the Mitochondria
27:10
Citric Cycle is Amphibolic - Works In Both Anabolic & Catabolic Pathways
32:06
Biosynthetic Processes
34:29
Anaplerotic Reactions Overview
37:26
Anaplerotic: Reaction 1
41:42
Section 11: Catabolism of Fatty Acids
Fatty Acid Catabolism I

48m 11s

Intro
0:00
Introduction to Fatty Acid Catabolism
0:21
Introduction to Fatty Acid Catabolism
0:22
Vertebrate Cells Obtain Fatty Acids for Catabolism From 3 Sources
2:16
Diet: Part 1
4:00
Diet: Part 2
5:35
Diet: Part 3
6:20
Diet: Part 4
6:47
Diet: Part 5
10:18
Diet: Part 6
10:54
Diet: Part 7
12:04
Diet: Part 8
12:26
Fats Stored in Adipocytes Overview
13:54
Fats Stored in Adipocytes (Fat Cells): Part 1
16:13
Fats Stored in Adipocytes (Fat Cells): Part 2
17:16
Fats Stored in Adipocytes (Fat Cells): Part 3
19:42
Fats Stored in Adipocytes (Fat Cells): Part 4
20:52
Fats Stored in Adipocytes (Fat Cells): Part 5
22:56
Mobilization of TAGs Stored in Fat Cells
24:35
Fatty Acid Oxidation
28:29
Fatty Acid Oxidation
28:48
3 Reactions of the Carnitine Shuttle
30:42
Carnitine Shuttle & The Mitochondrial Matrix
36:25
CAT I
43:58
Carnitine Shuttle is the Rate-Limiting Steps
46:24
Fatty Acid Catabolism II

45m 58s

Intro
0:00
Fatty Acid Catabolism
0:15
Fatty Acid Oxidation Takes Place in 3 Stages
0:16
β-Oxidation
2:05
β-Oxidation Overview
2:06
Reaction 1
4:20
Reaction 2
7:35
Reaction 3
8:52
Reaction 4
10:16
β-Oxidation Reactions Discussion
11:34
Notes On β-Oxidation
15:14
Double Bond After The First Reaction
15:15
Reaction 1 is Catalyzed by 3 Isozymes of Acyl-CoA Dehydrogenase
16:04
Reaction 2 & The Addition of H₂O
18:38
After Reaction 4
19:24
Production of ATP
20:04
β-Oxidation of Unsaturated Fatty Acid
21:25
β-Oxidation of Unsaturated Fatty Acid
22:36
β-Oxidation of Mono-Unsaturates
24:49
β-Oxidation of Mono-Unsaturates: Reaction 1
24:50
β-Oxidation of Mono-Unsaturates: Reaction 2
28:43
β-Oxidation of Mono-Unsaturates: Reaction 3
30:50
β-Oxidation of Mono-Unsaturates: Reaction 4
31:06
β-Oxidation of Polyunsaturates
32:29
β-Oxidation of Polyunsaturates: Part 1
32:30
β-Oxidation of Polyunsaturates: Part 2
37:08
β-Oxidation of Polyunsaturates: Part 3
40:25
Fatty Acid Catabolism III

33m 18s

Intro
0:00
Fatty Acid Catabolism
0:43
Oxidation of Fatty Acids With an Odd Number of Carbons
0:44
β-oxidation in the Mitochondrion & Two Other Pathways
9:08
ω-oxidation
10:37
α-oxidation
17:22
Ketone Bodies
19:08
Two Fates of Acetyl-CoA Formed by β-Oxidation Overview
19:09
Ketone Bodies: Acetone
20:42
Ketone Bodies: Acetoacetate
20:57
Ketone Bodies: D-β-hydroxybutyrate
21:25
Two Fates of Acetyl-CoA Formed by β-Oxidation: Part 1
22:05
Two Fates of Acetyl-CoA Formed by β-Oxidation: Part 2
26:59
Two Fates of Acetyl-CoA Formed by β-Oxidation: Part 3
30:52
Section 12: Catabolism of Amino Acids and the Urea Cycle
Overview & The Aminotransferase Reaction

40m 59s

Intro
0:00
Overview of The Aminotransferase Reaction
0:25
Overview of The Aminotransferase Reaction
0:26
The Aminotransferase Reaction: Process 1
3:06
The Aminotransferase Reaction: Process 2
6:46
Alanine From Muscle Tissue
10:54
Bigger Picture of the Aminotransferase Reaction
14:52
Looking Closely at Process 1
19:04
Pyridoxal Phosphate (PLP)
24:32
Pyridoxamine Phosphate
25:29
Pyridoxine (B6)
26:38
The Function of PLP
27:12
Mechanism Examples
28:46
Reverse Reaction: Glutamate to α-Ketoglutarate
35:34
Glutamine & Alanine: The Urea Cycle I

39m 18s

Intro
0:00
Glutamine & Alanine: The Urea Cycle I
0:45
Excess Ammonia, Glutamate, and Glutamine
0:46
Glucose-Alanine Cycle
9:54
Introduction to the Urea Cycle
20:56
The Urea Cycle: Production of the Carbamoyl Phosphate
22:59
The Urea Cycle: Reaction & Mechanism Involving the Carbamoyl Phosphate Synthetase
33:36
Glutamine & Alanine: The Urea Cycle II

36m 21s

Intro
0:00
Glutamine & Alanine: The Urea Cycle II
0:14
The Urea Cycle Overview
0:34
Reaction 1: Ornithine → Citrulline
7:30
Reaction 2: Citrulline → Citrullyl-AMP
11:15
Reaction 2': Citrullyl-AMP → Argininosuccinate
15:25
Reaction 3: Argininosuccinate → Arginine
20:42
Reaction 4: Arginine → Orthinine
24:00
Links Between the Citric Acid Cycle & the Urea Cycle
27:47
Aspartate-argininosuccinate Shunt
32:36
Amino Acid Catabolism

47m 58s

Intro
0:00
Amino Acid Catabolism
0:10
Common Amino Acids and 6 Major Products
0:11
Ketogenic Amino Acid
1:52
Glucogenic Amino Acid
2:51
Amino Acid Catabolism Diagram
4:18
Cofactors That Play a Role in Amino Acid Catabolism
7:00
Biotin
8:42
Tetrahydrofolate
10:44
S-Adenosylmethionine (AdoMet)
12:46
Tetrahydrobiopterin
13:53
S-Adenosylmethionine & Tetrahydrobiopterin Molecules
14:41
Catabolism of Phenylalanine
18:30
Reaction 1: Phenylalanine to Tyrosine
18:31
Reaction 2: Tyrosine to p-Hydroxyphenylpyruvate
21:36
Reaction 3: p-Hydroxyphenylpyruvate to Homogentisate
23:50
Reaction 4: Homogentisate to Maleylacetoacetate
25:42
Reaction 5: Maleylacetoacetate to Fumarylacetoacetate
28:20
Reaction 6: Fumarylacetoacetate to Fumarate & Succinyl-CoA
29:51
Reaction 7: Fate of Fumarate & Succinyl-CoA
31:14
Phenylalanine Hydroxylase
33:33
The Phenylalanine Hydroxylase Reaction
33:34
Mixed-Function Oxidases
40:26
When Phenylalanine Hydoxylase is Defective: Phenylketonuria (PKU)
44:13
Section 13: Oxidative Phosphorylation and ATP Synthesis
Oxidative Phosphorylation I

41m 11s

Intro
0:00
Oxidative Phosphorylation
0:54
Oxidative Phosphorylation Overview
0:55
Mitochondrial Electron Transport Chain Diagram
7:15
Enzyme Complex I of the Electron Transport Chain
12:27
Enzyme Complex II of the Electron Transport Chain
14:02
Enzyme Complex III of the Electron Transport Chain
14:34
Enzyme Complex IV of the Electron Transport Chain
15:30
Complexes Diagram
16:25
Complex I
18:25
Complex I Overview
18:26
What is Ubiquinone or Coenzyme Q?
20:02
Coenzyme Q Transformation
22:37
Complex I Diagram
24:47
Fe-S Proteins
26:42
Transfer of H⁺
29:42
Complex II
31:06
Succinate Dehydrogenase
31:07
Complex II Diagram & Process
32:54
Other Substrates Pass Their e⁻ to Q: Glycerol 3-Phosphate
37:31
Other Substrates Pass Their e⁻ to Q: Fatty Acyl-CoA
39:02
Oxidative Phosphorylation II

36m 27s

Intro
0:00
Complex III
0:19
Complex III Overview
0:20
Complex III: Step 1
1:56
Complex III: Step 2
6:14
Complex IV
8:42
Complex IV: Cytochrome Oxidase
8:43
Oxidative Phosphorylation, cont'd
17:18
Oxidative Phosphorylation: Summary
17:19
Equation 1
19:13
How Exergonic is the Reaction?
21:03
Potential Energy Represented by Transported H⁺
27:24
Free Energy Change for the Production of an Electrochemical Gradient Via an Ion Pump
28:48
Free Energy Change in Active Mitochondria
32:02
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Lecture Comments (3)

1 answer

Last reply by: Professor Hovasapian
Fri Mar 23, 2018 6:41 PM

Post by Swati Sharma on March 23, 2018

Dear Dr Rafi

Do you have lectures on Membrane Transport? and Signal Transduction Pathways as we are doing those chapter in class.

0 answers

Post by peter alabi on April 10, 2017

Hi, prof. Raffi,
Am just a little curious, and the following question may seem a little stupid.
1) knowing the fat soluble vitamins like ADEK are not water soluble, is it reasonable to ingest less of this set of vitamins as compare to water soluble vitamins, which probably get dissolve and excreted out easily?
2) In the previous lesson, you mentioned how the classes of galactolipids are found in the plants. I took the obligation to do some research, and one of the articles that I read postulated that plant uses the galactolipid to conserve phosphate for more rather important usage. Does this idea seem logical, if so, how come higher organism like vertebrates doesn't utilize a similar mechanism, I mean we need a constant supply and usage of phosphate more than plants?
3) During transformation process of e.coli in my biology lab, we used a competent cell for higher transformation efficiency, and I read that this  e.coli can be made competent by two methods, using divalent cation or electroporation, first if you don't mind explaining how this technique works in terms of the lipid bilayer.
And lastly, I think that using either divalent cation or electroporation is rather expensive, wouldn't it be better to introduce the cell to like a cold environment to facilitate the lipid bilayer to gel/solid phase, and then make some sort of incision in the cell membrane? kinda sound stupid I know.
4) Archean cell membrane lipid bilayer differ from both bacteria and eukaryotes in that they have ether linkage as compare to ester linkage, and secondly, they have L-glycerol as compare to D-glycerol in prokaryotes and eukaryotes, evolutionarily speaking would you say it significant? and does some of this structural differences account for why Archean are mostly extremophile?

Thank for the great lecture.

The Biologically Active Lipids

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
  • The Biologically Active Lipids 0:44
    • Phosphatidyl Inositol Structure
    • Phosphatidyl Inositol Reaction
    • Image Example
    • Eicosanoids
    • Arachidonic Acid & Membrane Lipid Containing Arachidonic Acid
  • Three Classes of Eicosanoids 20:42
    • Overall Structures
    • Prostagladins
    • Thromboxane
    • Leukotrienes
  • More On The Biologically Active Lipids 33:34
    • Steroid Hormones
    • Fat Soluble Vitamins
    • Vitamin D₃
    • Vitamin A
    • Vitamin E
    • Vitamin K

Transcription: The Biologically Active Lipids

Hello and welcome back to Educator.com and to Biochemistry.0000

We have been talking about lipids for the past couple of lessons, and today, what we are going to do is close out our discussion of lipids by talking about what I call "the biologically active lipids".0003

That is not to imply that the other lipids are not biologically active, but what I mean by that is that these lipids that we are going to talk about today, they are not used as fuel storage in the fat cells or sequestered in membranes.0012

In some sense, they are sort of locked in, not really moving around much.0028

By biologically active, I mean, something that is actually free to move around, and engaged in some sort of chemistry.0032

That is all I had meant by that; I did not mean to imply that the others were not biologically active.0037

OK, let's go ahead and get started.0042

Let's see; let's go ahead and start by discussing a molecule called phosphatidylinositol.0046

Let me go ahead and draw a structure here.0054

Let me see, where should I draw it?0057

And, let me go ahead and use blue; I always like blue.0059

Let's do, no, let's go this way; No, let's go a little bit further over here.0064

C, C, C, let's go, we have our (CH3)10, CH3.0070

And then, we have our O, and then we have our other carbonyl here.0086

And then, we have (CH2)7; then we have another C.0090

We have a double bond here, then we have a CH2.0097

It looks like we have another 7 and CH3.0104

So, this is our diacylglycerol part.0107

Again, we are just attaching something to glycerol; and, of course, well, not of course, in this particular case, we are going to have a glycerophosphate so glycerol.0110

We are going to have the phosphate linkage; we will go ahead and put that in, and we have our oxygen, so this is a phosphate ester.0123

And, let's go ahead and draw in what looks like a sugar unit.0132

This is going to be the...well, I will go ahead and draw things in, and then, I will go ahead and label.0137

So, that is that; that is that.0144

That is that, and that is that, and I will go ahead and label these.0147

This is 1, 2, 3, 4, 5, and 6.0152

In this particular case, this is the numbering on this particular section.0158

So, this is phosphatidylinositol or phosphatidyl - however you want to pronounce it - inositol.0163

And, it is a glycerophosphate or a phosphoglycerol - whatever - glycerine backbone.0177

It contains a phosphate- that is what is important.0186

All these names, they make me crazy, they always have.0189

I mean, they are kind of cool in the beginning, but eventually, they start to wear on you.0192

A glycerophosphate, let's just go ahead and call it that.0195

OK, something really, really interesting happens here.0201

Now, when this molecule is activated - this is an example of its biological activity - by an extracellular stimulus - something outside the cell - binds and activates it, gets this process going - stimulus extracellular - the following reactions take place.0205

I will just go ahead and write reaction; it is not a problem.0248

"The following reaction sequence", how is that?0251

OK, the following sequence takes place.0253

OK, let me go ahead, I wonder if I should start on this page or actually go to the next page.0261

You know what, let me just go ahead and start on this page; that is not a problem, so let me go back to blue.0267

I am just going to write "phosphatidylinositol".0272

OK, this is that; this is in the membrane.0278

This is a glycerophosphate; this is one of the lipids that happens to be in the membrane.0284

Now, I will go ahead and draw a little arrow here, like this.0292

Now, and I will go ahead and do my little biochemical arrows showing things coming in and things leaving, ADP.0296

This phosphatidylinositol is actually go to be phosphorylated; 2 phosphate groups are going to be attached to it.0308

We have 2 ATPs, and 1 phosphate from there is going to attach to this.0314

Another phosphate is going to attach, so let me just go ahead and write that.0320

Phosphorylation, while in the inner leaflet- in this particular case, it takes place on the inner leaflet of the membrane; and what I mean by that is, you have, of course, the outer leaflet, and this is outside the cell.0325

And then, of course, you have the inner leaflet; this is inside the cell.0352

Inner leaflet, it is the one that is facing inside the cell, so phosphorylation while on the inner leaflet of the cell membrane.0360

What happens is this thing ends up getting phosphorylated, and what you end up with is the following molecule.0374

You end up with phosphatidylinositol 4,5-biphosphate- that is it.0380

You take a couple of the phosphate groups from ATP; we spit out ADP.0391

We take those phosphate groups, and we are going to attach them to the 4 and 5, here and here- that is it.0394

I will not redraw the structure, but it is phosphatidylinositol 4,5-biphosphate.0400

We are going to call that PIP2 in just a minute.0405

OK, now, let me go ahead and go to the next page and rewrite this, so we can continue on with this reaction sequence.0407

Phosphatidylinositol 4,5-biphosphate, which we will call PIP2, something happens that is very, very interesting.0415

I am going to draw it this way; I am going to go...actually, let me make a little more room because I want to write right above the line.0431

That is one thing, and then, go ahead and do that.0444

Here, I will do this one in red.0451

An enzyme - oops - called phospholipase - phospholipase C, actually - in the membrane - it is actually in the membrane - hydrolyzes the glycerol phosphate bond.0455

Let me just draw it out really quickly on this side, here.0496

You had your - it is really tiny - you had this, right?0500

And then, you had your phosphate bond that goes on; so, it is going to break that bond, the glycerol phosphate bond.0505

OK, actually it is not true; it is going to end up breaking this one.0514

It is going to end up breaking this one, so water is going to hydrolyze this, so water is going to come and attach to that.0520

Phospholipase C is the membrane; it hydrolyzes the glycerol phosphate bond.0525

It is actually water that is coming in, and it separates this into 2 separate molecules.0530

The first molecule that it separates into, is IP3; and this is called inositol triphosphate.0535

It is just the 6-membered ring plus the phosphate and the 2 other phosphates that are attached to it, so inositol triphosphate.0549

This IP3 is released into the cytosol.0560

Remember, we said it is on the inner leaflet?0564

Once it breaks that, the IP3 molecule just floats into the cytosol.0566

I will show you a picture of it in just a minute, so do not worry about that.0571

OK, and the other, of course, is the diacylglycerol that, it stays in the membrane.0581

I do not need to put parentheses around it; that is fine.0596

The diacylglycerol part, it stays in the inner leaflet of the membrane.0598

OK, now, here is what happens.0608

This IP3 that is now in the cytosol, it causes the release of calcium ion from the endoplasmic reticulum, from the ER.0611

I will just put ER for endoplasmic reticulum.0632

Now, the calcium ion and the diacylglycerol that is still attached to the membrane, they activate together- the calcium and the diacylglycerol - they activate an enzyme.0635

Well, we will just give the name here, protein kinase C; and we just call that PKC- very, very important enzyme.0658

PKC, protein kinase C, it begins its function of regulating further enzymes by phosphorylation.0673

Let's just recap, and then we will go ahead and take a picture of it.0703

You have this phosphatidylinositol; an extracellular stimulus ends up causing it to be phosphorylated.0707

It ends up breaking it up; actually it phosphorylates it, and so what you end up with is this phosphorylase phosphatidylinositol 4,5-biphosphate, the PIP2.0719

Phospholipase C in the membrane, it hydrolyzes the glycerol phosphate bond.0730

It breaks it up into 2 separate things: the IP3 is released into the cytosol.0735

The diacylglycerol stays in the membrane; the IP3 causes the release of calcium from the endoplasmic reticulum.0739

The calcium and the diacylglycerol activate protein kinase C, and protein kinase C starts its function of regulating further enzymes to do whatever it is that they are going to do- this signal pathway that is taking place from this phosphatidylinositol.0745

OK, now, let's go ahead and take a look at this schematically or diagrammatically here.0764

OK, here is what is happening.0771

Now, what we have done is we have this phosphatidylinositol, and it is going to end up being phosphorylated.0774

So, now, it is going to be PIP2, right?0780

We have our PIP2; this is extracellular.0783

This is outside the cell; this is inside the cell.0785

This is the membrane, right here, in green.0790

I will go ahead and go to...no, that is fine; I will go ahead and leave it as red.0792

Now, here is what happens; the phospholipase C actually breaks off the inositol part, the polar part; and it releases it into the cytosol.0796

OK, this IP3 interacts with the receptor, the endoplasmic reticulum; and it causes calcium to be pumped out into the cytosol.0808

The calcium binds to protein kinase C; protein kinase C binds to the diacylglycerol, which was still in the membrane, and together, that combination, it starts a new series of events.0819

It starts phosphorylating enzymes which go and do whatever it is that they are going to do.0831

This phosphatidylinositol serves as a biologically active lipid.0837

It serves as a, basically, starting a series of signals to go on and do whatever it is that the cell needs to do- that is it.0844

OK, now, let's move on; let's go back to blue here.0853

Now, let's talk about another class of biologically active lipids.0859

They are called the eicosanoids, and what they are is paracrine hormones; and they act only on cells near.0865

This is what paracrine means; paracrine means they act very near the place where they are actually made.0893

They are not actually sent; they are not pumped into the blood and sent to different parts of the body like other hormones.0900

This is a paracrine hormone; it acts very, very locally.0906

That act only on cells near the region of hormone synthesis - let's just go ahead and make sure we write all this out - and not transported in the blood to remote tissues.0911

In general, when we think of hormones, that is what we are thinking about.0946

We are thinking about hormones that are pumped into the blood and sent out to other parts of the body to do whatever it is that they need to do...remote tissues and cells.0949

OK, now, let's write this one in red.0959

Their effects are both very diverse and very profound.0966

So, these eicosanoid hormones, there are a lot of things that they do, not just 1 or 2 things that they do- lots of different things that they do.0979

And, when they do them, they do them very, very profoundly; the effect is very, very deep.0988

These are not mild hormones, by any means.0993

And, let's see, what else?0999

All of them, they are derived from something called arachidonic acid.1003

OK, and we will be showing you some pictures in just a minute; and let me go back to blue for this one- membrane phospholipids.1012

Arachidonic acid is just a fatty acid- that is all it is.1022

It just has a certain length, carbon, has some double bonds in it, but it is just a fatty acid.1035

As a fatty acid, it can participate in reacting with a glycerol to form some glycerophosphate that is in the membrane.1041

So, membrane phospholipids containing the arachidonic acid are hydrolyzed when needed by an enzyme called a phospholipase A2 - to be exact - to release arachidonate.1054

And remember, when we say arachidonate, it just means it is the ionized form.1072

Arachidonic acid is protonated, arachidonate- deprotonated.1076

OK, that is what happens.1079

These eicosanoids are paracrine hormones; they act only on cells near the region of hormone synthesis, and they are not transported in the blood to remote tissues and cells.1082

Their effects are diverse and profound; they are all derived from arachidonic acid, and the arachidonic acid comes from the membrane phospholipids that contain it and are hydrolyzed when needed.1108

OK, let's go ahead and take a look here, see what we have got.1122

This is some membrane phospholipid and notice, here are glycerols.1126

Let's go ahead and mark off the glycerol part.1132

That is 1 carbon; that is 2 carbons.1135

That is 3 carbons; on one of them, we have, of course, our phosphate group.1138

And, of course, this is our polar head group, OK?1143

This looks like choline here, and then, of course, we have this one; and here, of course, we have the ester linkage, our first fatty acid, diacylglycerol.1145

Here is one of them; here is the other one.1154

In this particular case, this is our arachidonic acid right here; it has attached an ester linkage to the glycerol.1156

What it does, it actually hydrolyzes that, so it breaks this; and it ends up creating our arachidonic acid.1162

This, right here, is a membrane lipid containing the arachidonic acid.1172

And, this is our arachidonic acid right here; and, of course, once we break that, this is our arachidonic acid, our fatty acid.1190

This is arachidonic acid or arachidonate; it does not really matter.1197

Arachidonate just means you have deprotonated that, and now, you have a negative charge on it- that is it.1204

1, 2 , 3, 4, 5, 6, 7, 8, 11, 12, 13, 14, that is it- 4 double bonds.1210

1, 2, 14, 15, 16, 17, 18, 19, 20, this would be 20 carbons.1220

There are 4 double bonds, and you have a delta 5, 8, - what did we say, 11, 14 - yes, 11, 14.1230

That would be the delta notation for arachidonic acid- that is it.1237

OK, now, let's talk about the classes of the eicosanoids.1242

There are 3 classes of eicosanoids.1248

You have the prostaglandins.1261

You have thromboxanes, and you have the leukotrienes.1267

OK, let's take a look at some of these and see what we can do; and we will talk a little bit about each one.1282

Prostaglandins, thromboxanes, leukotrienes- all of them are eicosanoids.1293

They serve different purposes.1298

Let's see what we have got.1301

OK, we have got arachidonic acid, so I just wanted to put it up there, just for you to see it again.1302

Let me just write here.1309

From arachidonic acid, we end up forming - let's see what we have got here, well, let me just go ahead and write out what the names of these are.1317

Here, we have, this is a prostaglandin.1327

This happens to be prostaglandin A1, I think, yes, and notice, - well, let me just write it out - and then, over here, we have the thromboxane.1336

And then, I will go ahead and list some properties for each of these; and here, we have the leukotriene.1347

And, of course, triene, yes, you have got your conjugated triple bond, which is one of the characteristics.1357

This happens to be leukotriene before, and this is thromboxane A21363

OK, that is not A; well, that is fine, I will go ahead and write it like that.1371

OK, now, let's talk about some of these things.1376

Let's start off with our prostaglandins; let me go back to black here.1379

Prostaglandins, OK, an example of a prostaglandin, and example of a thromboxane, and an example of a leukotriene, and, of course, there are characteristic features here; so the prostaglandins, they contain a 5-membered ring.1387

There is your 5-membered ring.1410

OK, there were 2 groups originally called the PGEs and the PGFs, so the prostaglandin E series, the prostaglandin F series.1411

Now, there are other groups, there are others like the one above.1439

This is the prostaglandin A series, prostaglandin A1, prostaglandin A2, A3, whatever, just like prostaglandin E1, E2, E3, prostaglandin F1, F2, F3- that is it.1447

PGE, PGF, PGA and so on and so forth, as more and more get discovered, I guess.1457

And there are others; let me see, now, there are others.1467

Let's see what else can we say about prostaglandins.1471

OK, let's talk a little bit about what they do.1474

Prostaglandins often regulate the synthesis.1476

Again, a lot of these molecules, they do not just do one thing directly - they can - but often, what they do is they start a process, and that process has several different steps down the line.1488

You can speak of it doing this, but what it ultimately does is, maybe, this.1499

In this particular case, prostaglandins, they often regulate the synthesis of 3 prime, 5 prime, cyclic adenosine monophosphate and intracellular secondary messenger.1507

And, what we mean by secondary messenger is, let's say, from outside the cell, there is a primary messenger, some sort of a molecule that binds to the outside of the cell.1543

Something happens and it signals the inside of the cell; the inside of the cell produces 3 prime, 5 prime cyclic adenosine monophosphate, that is mediated by the production of some prostaglandin.1551

And then this 3, 5, CMP goes on to do what it does, so it is a secondary messenger.1565

It is down the line a little bit, tertiary messenger, quaternary messenger- things like that.1571

OK, let me go ahead and draw the structure, quickly, of this thing.1576

We have got our...let's see here, just so you know what it looks like.1580

Boom, boom, boom, boom, boom, boom, OK, we have our OH.1585

We have our O; let's go ahead and put the phosphate here.1592

Let's go ahead and put...this is ADNI; and you remember, the ADNI itself takes the normal numbers.1597

The sugar takes the prime numbers. This is 1 prime, 2 prime, 3 prime.1604

This is 4 prime, and this is the CH2; the is the 5 prime.1612

We have got O; that is that, and let me go ahead and put the double bond here, and I will go ahead and do that.1620

This is cyclic adenosine monophosphate 3 prime, 5 prime, if you want to be specific about where it is connected- that is it - that is prostaglandins.1628

OK, let's do some information about thromboxanes; let's go ahead and do this in blue.1641

We have our thromboxanes; now, for these, we have a 6-membered ring.1648

They have 6-membered rings containing an ether.1659

OK, they are synthesized by platelets and are involved in blood clotting, hence their name thromboxane, thromb.1669

OK, and this one is definitely good to know, NSAIDs.1705

OK, such as aspirin and ibuprofen, NSAID, non-steroidal anti-inflammatory drug.1714

An aspirin is an NSAID; an ibuprofen is an NSAID.1730

These things, they block the synthesis of prostaglandins and thromboxanes by inhibiting the enzyme prostaglandin - actually, I am going to go ahead and just write the enzyme; yes, I will go ahead and write it out, that is not a problem - H2 synthase, better known as cyclooxygenase - God, these names, just longer and longer and longer - also called C-O-X, COX.1735

These non-steroidal anti-inflammatorys like aspirin, like ibuprofen and there are several others, they block the synthesis of the prostaglandins and the thromboxanes.1799

They inhibit an enzyme called prostaglandin H2 synthase, otherwise known as cyclooxygenase.1808

This is an enzyme that you are going to talk about a lot for those of you that go on in biomedicine.1813

OK, let's say a couple of words about the leukotrienes here.1820

Let's see, do I have another page available?1824

I do, so you know what I am going to do?1828

I think I will go ahead and no, that is fine.1829

Let's go ahead and do this one in red.1834

Now, let's say a couple of words about the leukotrienes.1837

The leukotrienes, they happen to contain 3 conjugated double bonds.1843

So, if you go back to that picture, you will see that 3 of the bonds - they might have more double bonds than that, like in the picture, I think we had 4 double bonds - but 3 of them are going to be conjugated.1850

They are going to be one after the other; not directly after the other, it is going to be double, single, double, single, double single- that way.1860

That is what conjugated means; there is always a single bond between them.1866

It contains 3 conjugated double bonds; that is a characteristic feature.1869

That is the triene part, but that does not mean it has only 3.1877

It might have more; it might have there only 3, but it might have more.1880

So, 3 conjugated double bonds and let's see.1885

They are involved in inflammatory responses.1890

You know what, let me just go to the next page, let's see.1914

OK, in particular, leukotriene D4 is responsible for constriction of the airway during an asthma attack or during anaphylactic shock or anaphylaxis.1920

Let's go ahead and write it that way.1975

Oh, spelling, spelling, spelling, anaphylaxis- there we go.1980

This particular leukotriene D4, that is what is responsible, let's say, if you are allergic to nuts and your throat closes up, that is what does it- there you go.1986

OK, now, let's talk a little bit about steroid hormones; let me see here.1996

Do I have, yes, do I have them there?2002

I wonder if I should do it on the next page; yes, let me go ahead and actually write everything on the next page because we have the pictures on the next page.2005

Let me go ahead and move over here; let's talk about the steroid hormones.2015

This is another class of biologically active lipids.2020

They are lipids; they have certain biological activity as free molecules.2027

Now, they have the sterol ring structure, as you see, 1, 2, 3, 4, 1,2 ,3 ,4, 6, 6, 6, 5, 6, 6, 6, 5, A, B, C, D.2037

Remember we talked about sterol ring structure.2055

A ring structure but lack the alkyl chain on ring D.2062

So, you remember, when we look at the sterol structure, this is ring D right here.2077

OK, remember there was this long alkyl chain attached to it?2084

These have the basic structure; they have the 4 rings, but they lack that alkyl chain.2088

And as you can see, they actually have other polar groups up here.2092

Now, they are highly oxidized and reasonably polar.2096

And again, I mean, mostly we have this carbon, this hydrocarbon basic structure; but you see in oxygen here, the carbonyl group.2115

You see the alcohol group over here, alcohol group over here, alcohol group over here.2123

It is reasonably polar, at least on the 2 ends; it is reasonably polar.2128

Now, they move through the blood stream attached to proteins, and they act on cells by entering them, interacting with highly specific receptors.2133

And when we mean highly specific, we are saying that a receptor recognizes just that particular molecule.2187

OK, receptors, and triggering changes in metabolism and gene expression.2193

These are very, very, very powerful hormones; I mean, they actually change gene expression.2213

They affect what proteins are now going to be built to do whatever it is that proteins do; they change metabolism.2219

They have deep fundamental impact on what the body does.2227

OK, over here, we have - let’s do this in red – testosterone.2232

The thing that essentially makes men, men, with all of their masculine characteristics, is a steroid hormone; this is testosterone.2246

Over here, we have the estradiol, one of the primary hormones that makes women, that gives them their particular characteristics.2256

These are very, very similar; this should show you that there is actually very, very little difference between men and women.2268

It is strictly a very, very small chemical difference, essentially the same molecule for all practical purposes.2275

There it is- 2 very, very powerful steroid hormones.2284

Obviously, very powerful because as you go to puberty, men develop 1 set of characteristics, women develop another set of characteristics; and these are the hormones that induce those things.2289

OK, now, let’s go ahead and finish off this discussion by talking about the fat soluble vitamins.2298

Let’s see here; our fat soluble vitamins are...I don’t know if should write them.2306

That is OK; I will go ahead and write it over here.2315

Our fat soluble vitamins: A, D, E and K.2318

Four vitamins that the body needs- they are fat soluble vitamins; let’s go ahead and see.2332

These are isoprenoids made by the condensation - just a fancy word for putting together - of multiple units of the molecule isoprene.2339

And let’s go ahead and just do a quick structure for isoprene: double bond C.2379

I will go ahead and put the H here, and then I will go ahead and put another bond there, CH2; and should I, yes, I will just go down below.2391

That is fine; this is isoprene 1, 2, 3, 4, 5.2400

When you polymerize this molecule, when you just put 1 isoprene unit and another isoprene unit and another isoprene unit, that is what that means.2404

These isoprenoid vitamins, the A, D, E and K, they are derived from isoprene, just a bunch of units.2412

They always come in increments of 5, so 5, 10, 15, 20, 25, 30, 35, 40.2422

That is the number of carbon atoms that you are going to find in these particular vitamins.2428

OK, this one over here, this is vitamin D3.2432

I hope I have enough room to write a little bit about these things.2437

Let’s see; this is, up here is vitamin D3, also called cholecalciferol.2442

Now, this is a prehormone; in this particular form, it is not really doing anything.2457

Well, what ends up happening, so it is connected; this is converted to 1,25-dihydroxy D3.2464

What we mean by that is: one step in the kidney, one step in the liver.2487

Each one of those steps attaches a hydroxy at the no. 1 carbon, at the no. 25 carbon.2494

Now, what you have is 1,25-dihydroxycholecalciferol; this is the biologically active form of vitamin D3.2501

OK, and what this does is it regulates calcium uptake, calcium levels and uptake, intimately involved in the incorporation of calcium into your teeth and bones.2510

There is a lot about vitamin D that we actually do not know yet, and that is kind of the exciting part.2531

The field is wide open for how this thing does what it does, why it does what it does and does it do other things- very, really, very, very exciting.2536

For all of these fat soluble vitamins, we actually don not know very much about them at all.2545

OK, now let’s see here.2550

This is vitamin A; let me go ahead and go to blue for this one.2554

I am going to go ahead and just write what they are here, and on the next page, I am going to talk a little bit about them.2563

I wanted to do it on the same page, but it is not a problem; this is our vitamin A.2568

OK, and this is our, yes, I will go ahead and do it over here; that is fine.2575

This is vitamin E, and this is vitamin K.2585

OK, now, I am going to go ahead and move to a new page and write a little bit about each.2591

Let’s talk a little bit about vitamin A, and after this, we will go ahead and close off the discussion of the biologically active lipids.2597

So, it is a hormone.2606

OK, it also happens to be a visual pigment of the vertebrate eye.2610

OK, the vertebrate eye.2625

So when you see, it is vitamin C actually doing something with this protein called opsin.2630

We will discuss it later on, but it is what actually ends up sending the signals to your brain to let you know that you actually see and what it is that you see, so very, very important.2638

It is also a prehormone, and it is a bioactive form, has a hormone- is retinoic acid.2648

When you look at the molecule, you have that hydroxy at the end.2669

Well, this thing is converted to an aldehyde, and then it is converted, again, to a carboxylic acid.2678

Everything else stays the same when it is turned into the retinoic acid that becomes the active form of the hormone that goes and does what it does.2685

That is a different function from its function as a visual pigment.2692

It acts a visual pigment in one form called retinal, the aldehyde form, and then, when it is oxidized, again, to retinoic acid, it goes and does something else as it serves another hormonal function.2698

OK, let’s talk about vitamin E a little bit.2713

OK, they are called tocopherols.2720

When we talk about vitamin E, we are not talking about just 1 particular molecule.2728

I gave you a picture of one particular molecule.2733

There are slight changes in that, and that whole class of molecules that look like that, that have certain changes, those we call the tocopherols.2735

Vitamin E is like a series of molecules that are very, very, very similar.2744

And we call them the tocopherols, but we refer to it as vitamin E, so just so you know; and vitamin E is an antioxidant- very, very powerful antioxidant.2749

And antioxidants, they do one thing- they react with oxygen radicals.2761

And you remember from organic chemistry, a radical is something that has just 1 electron instead of 2 electrons, so they are highly reactive species - oxygen radicals and other free radicals, not just oxygen radicals and other free radicals - to prevent the oxidation of membrane lipids.2770

Lipids are very, very prone to oxidation very, very easily.2806

What vitamin E does is it keeps them from oxidizing, so that they can maintain the integrity of the cell- that is what it is - it runs interference.2811

These oxygen radicals and these other free radicals that are produced in the normal course of metabolism, they are going to react with lipids; and they are going to do all kinds of damage.2820

Well, vitamin E prevents that by reacting with them, so that they cannot react with the lipids in the membranes.2830

OK, and now, let’s go ahead and say - you know what, let me go ahead and use the next page - a couple of words about vitamin K, and we should be done.2837

Vitamin K, it is intimately involved with prothrombin, a blood plasma protein involved in - you guessed it - involved in blood clotting.2848

Vitamin K- very, very important for blood clotting.2888

And again, these fat soluble vitamins, we know a lot about them; but we do not know a lot about them.2893

It is a very, very fertile area of research; and I could just imagine the things that we are going to be discovering over the next 10, 20 years for these particular vitamins.2900

Thank you for joining us here at Educator.com, and this closes out our discussion of lipids.2910

Take care, see you soon, bye-bye.2915

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