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Raffi Hovasapian

Raffi Hovasapian

Fatty Acid Catabolism I

Slide Duration:

Table of Contents

I. 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
II. 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
III. 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
IV. 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
V. 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
VI. 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
VII. 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
VIII. 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
IX. 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
X. 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
XI. 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
XII. 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
XIII. 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 (2)

1 answer

Last reply by: Professor Hovasapian
Tue Sep 10, 2013 8:34 PM

Post by Vinit Shanbhag on September 9, 2013

Nice explanation:
I was wondering if the fatty acids of 12 and less carbons are also converted into S-COA and than transported or they just get into the membrane with charge on it coo-? since charged molecules cant enter the membrane. Plz correct.

Fatty Acid Catabolism I

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
  • Introduction to Fatty Acid Catabolism 0:21
    • Introduction to Fatty Acid Catabolism
  • Vertebrate Cells Obtain Fatty Acids for Catabolism From 3 Sources 2:16
    • Diet: Part 1
    • Diet: Part 2
    • Diet: Part 3
    • Diet: Part 4
    • Diet: Part 5
    • Diet: Part 6
    • Diet: Part 7
    • Diet: Part 8
    • Fats Stored in Adipocytes Overview
    • Fats Stored in Adipocytes (Fat Cells): Part 1
    • Fats Stored in Adipocytes (Fat Cells): Part 2
    • Fats Stored in Adipocytes (Fat Cells): Part 3
    • Fats Stored in Adipocytes (Fat Cells): Part 4
    • Fats Stored in Adipocytes (Fat Cells): Part 5
  • Mobilization of TAGs Stored in Fat Cells 24:35
  • Fatty Acid Oxidation 28:29
    • Fatty Acid Oxidation
    • 3 Reactions of the Carnitine Shuttle
    • Carnitine Shuttle & The Mitochondrial Matrix
    • CAT I
    • Carnitine Shuttle is the Rate-Limiting Steps

Transcription: Fatty Acid Catabolism I

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

We just finished discussing the citric acid cycle and the breakdown of carbohydrates.0004

Now, we are going to start discussing the breakdown of the fats, of the lipids.0010

We are going to be discussing fatty acid catabolism, so let's just jump right on in.0016

OK, the oxidation of fatty acids to acetyl-CoA, you notice that fatty acids are also catabolized to acetyl-CoA just like the pyruvate was that entered the citric acid cycle.0022

It is broken down into acetyl-CoA, and these acetyl-CoAs actually enter the citric acid cycle.0050

The oxidation of fatty acids to acetyl-CoA is a major source of energy for organisms.0055

In fact, it is probably the major source.0070

OK, complete oxidation of fatty acids - I will just go ahead and abbreviate it as FAs - releases about 40kJ/g.0075

For a gram of fat, it releases about 40kJ of heat - that is a lot of energy - more than twice that released by an equal mass of either protein or carbohydrate.0101

OK, now, vertebrate cells obtain the fatty acids that they need - obtain FAs - for catabolism from 3 sources.0137

In other words, the fatty acids that the cell needs in order to burn to get energy, they come from 3 different sources.0168

There are 3 ways that the fatty acids get to the cells, in other words.0176

One of them is diet.0180

What you eat, it finds its way directly to the cells.0184

Two: is the fats that are stored in cells already.0189

Sometimes, it will just mobilize those fats that are already there and use them for breakdown, and the third way is the fats that are synthesized by one organ then, transported to the tissues that need them.0199

OK, let's talk about diet first.0237

No. 1: diet, dietary fats are absorbed by the small intestine.0242

Now, we will just go ahead and list how it actually does this.0268

In your biochemistry books, there is probably some illustration of some sort that talks about how it goes from the intestine, how it gets here.0272

You are more than welcome to look at it; in fact, I encourage you to take a look at it.0279

What I am going to do here, I am not really going to be using any diagrams.0283

I am just going to be listing the process; it is important to know what happens, but we want to concentrate on the second one, the fats that are stored in cells, how those fats are actually mobilized, and that is when we are going to be looking at diagrams and pictures and following reactions very carefully.0286

Dietary fats are absorbed by the small intestines, and it happens as follows.0301

Bile salts emulsify dietary triacylglycerols.0309

Triacylglycerol, just fat, the fat that you ingest, you are ingesting it as triacylglycerols.0325

The bile salts that the body secretes actually emulsify them.0332

OK, now, 2: lipase enzymes, they break down these triacylglycerols - which I will abbreviate as TAGs - to monoacylglycerols, diacylglycerols, free fatty acids - free fatty acid, those are just those long chain carboxylic acids, we just call them free fatty acids - and glycerol.0336

OK, now, no. 3: these breakdown products, they are what is actually absorbed by the intestine.0380

These breakdown products are absorbed by the intestine.0395

OK, now, no. 4: these breakdown products - well, I will write that again - are reconverted back to the triacylglycerols, then, these TAGs are combined with cholesterol, cholesteryl esters and - excuse me - specific proteins into particles called chylomicrons; and certainly, there is a picture of a chylomicron in your book.0408

These triacylglycerols that are reformed, they are combined with cholesterol and the esters of cholesterol.0492

Cholesteryl ester is actually an ester of cholesterol, and these specific proteins, they are, sort of, combined into this particle.0502

The proteins are on, sort of, the outside of it, and these particles are called chylomicrons.0510

OK, I want to say a word about these specific proteins.0517

Now, these specific proteins are called apolipoproteins, and they are responsible for actually transporting the lipids through the bloodstream because fats, as you know, are not water soluble.0521

So, they cannot just float around in the blood or the lymph.0551

They have to be solubilized - if you will - by these proteins.0557

They attach to proteins, and the proteins carry them to where they need to be.0561

These specific proteins are called apolipoproteins, and they are responsible for transporting insoluble lipids through the bloodstream and lymphatic system.0565

OK, one of these proteins, APOC2 is an example.0604

That is the name of it- APOC2.0613

OK, excuse me; let's see what happens next.0617

Alright, no. 5: these chylomicrons are transported via blood and lymph to the various tissues.0623

OK, now, no. 6: in the capillaries, when they reach the end of their respective journeys, the enzyme lipoprotein lipase - or lipase if you want, I say lipase - recognizes the APOC2 that I mentioned earlier - one of those lipoproteins, it recognizes the APOC2 - and starts breaking down, hydrolyzing - yes, that is fine - the triacylglycerols, the TAGs to free fatty acids and glycerol- that is it.0653

And then, the fatty acids, at this point, that is when they enter the cells.0725

Fatty acids enter cells of the tissues, at this point.0732

OK, now, no. 8: OK, the fatty acids, once they are in the cell, the FAs are either oxidized to release the energy, or they are re-esterified to store as triacylglycerols.0745

They are reesterified - in other words, the free fatty acids and the glycerol are put back together in order to store them for future use - to the triacylglycerols, which they were originally, for storage, and that is it.0786

OK, now, let's go ahead and talk about...this is how the fats that we ingest in our diet, how they get to the particular cells.0807

Now, the other way that free fatty acids, that triacylglycerols, the fats, are actually mobilized in order to be used are there are the fat that is actually stored in the cells, how do we use that fat?0818

Well, now, we will talk about that.0832

No, 2: let's go ahead and do this one in blue.0836

No. 2: fats that are already stored in adipocytes - adipocytes, however you want to pronounce it - fat cells.0840

They are cells where fat is stored as just as fat, just straight triacylglycerols.0854

OK, now, excuse me.0863

Fats stored in adipocytes are mobilized by the hormones glucagon and epinephrine, which are secreted by the body in response to low blood glucose levels.0868

If your blood glucose rises too high, at that point, that is when the body pumps in insulin.0925

That is the hormone that starts to break that down to regulate high blood glucose.0929

If your blood sugar drops too low, glucagon and epinephrine are secreted, in order to, in this particular case, mobilize free fatty acids.0935

That is all that is going on here; OK, now, let's run through the process.0944

Now, in this particular case, what I am going to do is I am going to list the process 1, 2, 3, 4, 5, and then, we will actually take a look at a diagram of a cell, so that we can see it visually as well.0948

I would like you to have it written out, and I would like you to also have it visually, so we will go through this twice.0958

If there is anything in the written part that you do not necessarily understand, we will go through it again, and we will see it.0965

When we see it pictorially, it should make sense what is happening in the cell.0969

OK, no. 1: now, the hormone, it stimulates the enzyme - well, you do not have to - it stimulates adenylyl cyclase via a G protein to produce cyclic adenosine monophosphate.0974

There is this enzyme that is in the outer membrane, and it stimulates this adenylyl cyclase via something called a G protein to produce this thing called cyclic adenosine monophosphate.1023

OK, now, 2: cyclic adenosine monophosphate - cAMP - it is a secondary messenger inside the cell, which induces a protein called cAMP-dependent protein kinase to phosphorylate 2 things, right?1037

A kinase does 1 thing, so this cyclic adenosine monophosphate is a secondary messenger.1085

It stimulates this cAMP-dependent protein kinase to phosphorylate 2 things.1090

OK, the first thing that it phosphorylates is something called a hormone-sensitive lipase, and we know what lipases do.1108

Lipases break down lipids, triacylglycerols.1118

OK, it also phosphorylates something called a perilipin.1122

It also phosphorylates something called the perilipins, which are proteins on the outer surface of the lipid droplets that is in the cell.1128

The fat that is in the cell that is, sort of, aggregated on the surface of that fat collection are these things called perilipins on the outer surface of the lipid droplets in the adipocytes.1157

OK, no. 3: OK, hormone-sensitive lipase, once it phosphorylates this thing called hormone-sensitive lipase, the hormone-sensitive lipase, which is floating around in the cytosol, it actually moves around in the droplet, moves toward the lipid droplet, and it starts hyrdolyzing the triacylglycerols.1182

It starts breaking them down - the triacylglycerols - into free fatty acids and glycerol.1230

It basically takes those triacylglycerols and just cuts them off to release the free fatty acids and to release the glycerol.1245

OK, now, let's go to no. 4.1253

Now, the free fatty acids, they pass from the adipocyte into the blood stream.1259

The free fatty acids pass from the fat cell - from the adipocyte - to the bloodstream where they combine with, where they bind to a protein called serum albumin - bind to serum albumin protein - which then, carries them to the various tissues - cells - where they are needed.1270

We have these cells, adipocytes, it is where the fat is stored.1337

If that fat is needed for some purpose, let's say you have not eaten all day, but the body needs some energy, and it wants to actually burn some fat, it is going to burn some of the fat that you have stored.1342

It is going to mobilize this fat, and once it breaks it down into the free fatty acids, it sends those free fatty acids outside of the fat cell into the blood stream, so that the blood stream, the serum albumin, can take those bound-free fatty acids to the cells, to the muscle tissue, in order to mobilize it and extract the energy.1355

That is all that is happening there; now, that takes care of the free fatty acids.1375

What about the glycerol?1379

OK, the glycerol left behind, and then, we have to account for everything.1380

We are not just going to leave molecules just hanging around and say nothing about them.1389

The glycerol that is left behind is phosphorylated by - you guessed it - glycerol kinase because that is what kinases do - they phosphorylate - to glycerol 3-phosphate, not glyceraldehyde-3-phosphate- glycerol 3-phosphate.1393

It is this; glycerol goes to glycerol 3-phosphate, which is then, converted into dihydroxyacetone phosphate, which is then, converted to glyceraldehyde-3-phoaphate; and you can see where we are going.1428

Glyceraldehyde-3-phosphate continues on with glycolysis.1452

It has ways of handling what is left over, and that is all that happens.1459

OK, now, what we want to do, now, that we have actually written this out, let's go ahead and take a look at a picture of this, and see what it looks like; so let's see here.1463

I think I have got it here; yes, here we go.1473

OK, do not worry; there is a lot going on here, but it just seems that way.1477

Once we actually start talking about what is going on, you are going to realize that everything is really, really, very, very clear.1482

Let's identify some things here; this is the fat cell.1488

OK, and this thing right here, this is the lipid droplet.1493

It is just a collection, an aggregate of fat- triglycerols.1498

This is the cell; now, on the cell surface, there is a receptor for the particular hormone.1504

In this particular case, whether it is glucagon or epinephrine, it does not really matter.1507

The hormone attaches to the receptor; it has been secreted by the body.1512

It attaches to the receptor; this receptor, now, via something called the G protein - do not worry about it if you do not know what the G protein is.1516

For our purposes, it is not necessarily...for those of you that have taken cell biology and have studied biosignaling, you know what a G protein is.1523

For those of you that do not, you will, so it is not a problem.1530

Just understand that through G protein, it stimulates this enzyme called adenylyl cyclase to use ATP to create something called cyclic adenosine monophosphate.1534

That is the secondary messenger; that is created inside the cell.1545

Well, this cyclic adenosine monophosphate travels to this thing, the cAMP dependent kinase, which we call PKA.1550

It stimulates the PKA to phosphorylate 2 things.1560

This enzyme ends up phosphorylating this thing called hormone-sensitive lipase, and it also ends up phosphorylating the perilipins.1565

Remember, we said the perilipins are these proteins that are on the surface of the droplet.1572

That is where the perilipins are; what they do is they actually restrict access to this lipid droplet, but once they are phosphorylated, they actually open up.1577

They open up, and they allow things to have access to the lipid droplet.1587

In this particular case, the thing that is going to have access to the lipid droplet is the hormone-sensitive lipase.1591

Once that is phosphorylated, it starts to move towards the lipid droplet; it makes its way in between the perilipin proteins, and then it just starts to hydrolyze it, starts to break them up.1597

Now it is in contact with the lipid droplet, here is just the triacylglycerol - right, a fat - it hydrolyzes them, and it releases into the cytosol the free fatty acids; and here is the glycerol left behind.1606

The free fatty acids, they enter the bloodstream and they bind, and they do whatever it is that they do.1623

They bind non-covalently to the serum albumin protein, and the serum albumin protein carries these free fatty acids to the cells that actually need the energy; and we already said what happens to glycerol.1629

Glycerol is phosphorylated, and it ultimately enters the glycolytic cycle.1641

That is all that is happening here, stimulation via hormone production of cyclic adenosine monophosphate.1646

Cyclic adenosine monophosphate stimulates PKA to phosphorylate hormone-sensitive lipase and the perilipins.1654

Hormone-sensitive lipase ends up hyrdolyzing the triacylglycerols to free fatty acids and glycerol.1661

Free fatty acids are released into the bloodstream to go where they needed.1666

Glycerol is rephosphorylated into - well, not re...it is phosphorylated - and it enters the glycolytic cycle- that is it.1670

The glycolytic pathway- sorry.1679

Pathway cycle it is the citric acid that is actually a cycle; glycolysis is a serial pathway- that is it.1681

OK, now, let's actually talk about fatty acid oxidation, itself.1689

Alright, now, let's talk about fatty acid oxidation.1698

I think I am going to go back to...I don't know.1703

Should I do red or should I do...no, I think I will go back to black.1705

We have got fatty acid oxidation.1710

OK, yes, OK, now, the fatty acids from the bloodstream, now, the serum albumin is carrying these free fatty acids to the cells that are going to need them - need the free fatty acids - in order to break them down and recover their energy.1719

The fatty acids from the bloodstream, they enter the cells where needed.1750

OK, now, fatty acid oxidation, it takes place in the mitochondrion.1767

Oxidation takes place - it seems like everything takes place in the mitochondrion, doesn't it - in the mitochondrion.1777

OK, now, fatty acids of 12 carbons or less, they enter the mitochondrion without the help of a transporter.1791

In other words, they just pass through the outer membrane and the inner membrane in going to the matrix.1825

They get into the mitochondrial matrix - we will see a picture in just a minute - very, very easily- the ones that have 12 carbons or less.1830

Fatty acids of 12 carbons or less, they enter the mitochondrion without the help of a transporter.1837

Now, those fatty acids with greater than or equal to 14 carbons - once this chain starts to get a little long, which is the majority, by the way - they must undergo 3 reactions of something called the carnitine shuttle in order to enter the matrix from outside- reactions of the carnitine shuttle in order to enter the mitochondrial matrix.1843

And again, we will see a picture in just a minute.1896

In other words, they do need some help getting in; they cannot just go across the membrane- the 14 carbons or more.1902

OK, let me go ahead and list the reactions, and then, we will go ahead and take a look at a picture of this.1910

The first reaction that they have to undergo is the following; let me go ahead and do this in blue.1915

Our first reaction is, we have a free fatty acid.1921

This is going to be R, C, O-.1927

OK, actually, you know what, I think I am going to write this a little bit lower because I need a little bit more room.1936

Let's put it down here; we have R.1947

We have C; we have some free fatty acid, and let's see.1951

We are going to have CoA.1957

Coenzyme A comes in. ATP is used.1963

AMP + PPI is released, then, we end up with R, C, O, O, S-CoA; and the enzyme that does this is called - oops, let's do the enzyme in red - fatty acyl-CoA synthetase.1975

The first reaction that has to happen is these free fatty acids are converted into the coenzyme ester- the thioesters, so R, C, O, O to R, C, O, S-CoA.2007

That is the first reaction that has to take place; now, the second reaction that has to take place is the following.2020

We have this, now, the R, C, O, S-CoA, and go ahead and do that.2027

Carnitine comes in, and CoA - I will just write it as CoA-SH - leaves, and what you end up with is now, this transesterification.2043

The coenzyme A is taken off, and carnitine is attached as an ester.2055

R, C, O, O, well, I will just go ahead and write carnitine because it is the oxygen on the carnitine that is this.2060

And then, our third reaction is going to be the following: R, C, O, carnitine, and it is reconverted once it is inside the matrix back to what it was supposed to be.2075

CoA-SH comes in, and carnitine leaves; and it is reconverted back into what it is supposed to be, which is S-CoA.2094

Let me go ahead and write the enzymes; let's do this.2111

This is called carnitine acyltransferase no. 1, and this is CAT no. 2- carnitine acyltransferase no. 2.2115

The reactions that have to take place are the following for any carbon, for any free fatty acid that has 14 carbons or more.2133

The free fatty acid is converted into the acyl-CoA.2141

The CoA is converted into the carnitine ester, and then, it is transported into the matrix at this point; and then, the carnitine ester is reconverted back to the acyl-CoA.2146

It is a way of taking this that is on the outside of the mitochondrion, getting it inside the mitochondrion and getting it here.2155

That is what we want; we are trying to get to this point because it is at this point that now, the mitochondrion can actually oxidize it, start turning it into the acetyl-CoA that it is going to turn it into.2165

OK, let's go ahead and take a look at this, what is actually going on in terms of...do a little diagram of what is going on here.2175

Let's see; aha, alright, here is a picture of the mitochondrion.2185

Basically, these free fatty acids are on the outside; they are out here.2189

OK, this is the cell; the mitochondrion is an organelle inside the cell.2193

This is the cytosol; they need to get in here.2198

What we have, no. 2, this is the outer membrane of the mitochondrion.2202

This, right here, that is the inner membrane of the mitochondrion.2206

4: the stuff that is in orange, that is the matrix.2213

That is where it needs to be; that is where it all happens.2217

This white space is actually the intermembrane space; it is in between the outer membrane and the inner membrane.2221

Now, what I am going to do is I am going to take a little section of it like this.2227

I am going to do this in black, I think; I am going to take a little section of it, and I am going to blow it up, so that you see it.2233

Actually, let me do it on this side because I am actually going to have the cytosol on the left.2240

Let's go ahead and take this portion right here; OK, there is the cytosol, the outer membrane, the intermembrane space, the inner membrane and the matrix.2246

We are going to have 1, 2, 3, 4, 5 things.2254

I am just going to magnify this, and we are going to see what is going on.2258

Let me go ahead and draw this out.2262

Actually, I do not need to make the space that big.2266

This is going to be the...that is the outer membrane.2270

Let's go ahead and do the inner membrane here.2277

OK, here, we have the cytosol; here, we have the intermembrane space.2283

That is the white; this is the outer membrane, and here, we have the actual matrix.2295

This is the orange part; OK, these free fatty acids that are out here, we need to get them from the cytosol into the matrix.2300

The carnitine shuttle does this; here is how it does it.2314

OK, I am going to draw something here, and I am going to draw a little something here.2317

Yes, that is fine; I guess I can draw it right there.2323

I am going to go ahead and draw this in blue.2327

This is our carnitine acyltransferase I, and I will go ahead and draw a little something here.2332

Hold on; let me do that and that.2340

This is this little transporter that we have.2350

OK, it basically splits it in half; it is basically something that the molecule can pass through on the inner membrane.2357

Let me go ahead and just list this; this is the outer membrane.2365

This is the inner membrane.2374

OK, I have just taken this, and I have magnified it- cytosol intermembrane space matrix.2379

Here is what happens; the first reaction goes ahead and takes place out here.2384

It is converted into its acyl-CoA, and then, we have the following.2389

Let me go ahead and do this in...I wonder if I should do this in...now, what color should I do it in?2394

That is fine; I will go ahead and leave it as blue.2401

OK, we have R, C, O, S-CoA, and we have carnitine.2406

This is the second reaction that is going to take place.2415

This is going to go that way; this is going to go that way.2420

The acyl-CoA and the carnitine are going to react.2423

It is going to release the coenzyme A, and what you are going to end up with is this R, C, O, O, carnitine.2429

Now, we are not sure whether this actually takes place outside in the cytosol and then goes into the intermembrane space or if it actually happens in the intermembrane space, but the CATI, they acyl tranferase is right there on the outer membrane.2438

At this point, this is transported across the intermembrane space and into here.2455

Now, we have R, C, O, carnitine.2464

Now, at this point, it is going to react with CoA, again.2473

This is the third reaction, and it is going to release carnitine; and it is going to be reconverted back to its R, C, O, S-CoA.2484

This is what we want; it is on the outside.2497

We want it to be on the inside; now, a carnitine comes back out through here to start the cycle again.2502

Alright, now, let's go ahead and just write a couple of things here.2510

This is the carnitine shuttle.2515

This is the carnitine shuttle, and let's just list a couple of things here.2520

Oh, let me put my other enzyme; my other enzyme is this one right here.2530

OK, this is my CATII.2541

Let's go ahead and do this in red- the 3 reactions of the carnitine shuttle.2548

The first one is taking a free fatty acid - this thing - turning it into acyl-CoA.2554

Once we have turned it into acyl-CoA, it actually reacts with carnitine.2563

The coenzyme A leaves; it turns it into a carnitine ester.2568

This carnitine ester passes through the intermembrane space, goes through this particular transporter - this transporter - and it brings it into the matrix as the carnitine ester.2573

Now, we can convert it back to the acyl-CoA that we need.2586

It reacts with the CoA that is inside the matrix; we have produced this.2590

We have released the free carnitine; now, the free carnitine passes back through the transporter, goes back over here, so it can start the cycle all over again.2595

That is the shuttle; it is taking an acyl-CoA on the outside of the - out in the cytosol - mitochondrion, and it is bringing it inside of the mitochondrial matrix.2602

That is what the carnitine shuttle does; that is all that is going on here.2614

Reaction 1 takes place here, so I will go ahead and put reaction 1 there.2617

This, right here, is reaction 2 of the carnitine shuttle, and this, right here, is reaction 3 of the carnitine shuttle; and this transporter is what actually affects it- that is it.2624

OK, now, let's go ahead and say a couple of words here.2636

The carnitine acyltransferase, the CATI, the one that actually converts the acyl-CoA to the carnitine ester, CATI is inhibited by malonyl-CoA, an intermediate in fatty acid biosynthesis.2645

This is to ensure that a synthesis - in other words, anabolism - and breakdown - catabolism - do not happen at the same time, do not happen simultaneously.2694

When the body is actually synthesizing fats - a fatty acid - one of the intermediates is this thing called malonyl-CoA.2730

Its presence actually stops, it actually inhibits this enzyme of the carnitine shuttle.2740

It stops the actually breakdown of the fat because that is the thing.2748

There are some times when the body needs fat, so it will synthesize it.2751

There are times when the body needs to break down the fat; if they happen simultaneously, nothing is really changing.2755

When it is producing, when it is biosynthesizing the fatty acid, it actually shuts down the breakdown of the fatty acid, so that you actually have a build-up of the fatty acid because the body needs it, otherwise, it is just going to make it-use it, make it-use it- nothing changes.2762

This is a point of regulation - a very important point of regulation - for the fatty acid catabolism.2778

OK, now, the final word here on the carnitine shuttle.2785

The carnitine shuttle is the rate-limiting step in fatty acid oxidation.2798

This carnitine shuttle, the rate at which it actually can enter the mitochondrion, that is ultimately the rate at which fatty acids can be oxidized.2813

This is what controls the rate; everything else is a very fast reaction.2822

This is what controls the rate; the carnitine shuttle is the rate-limiting step in fatty acid oxidation, and as such, is a point of regulation.2827

Now, remember what we said, the rate-limiting steps, the highly exergonic steps in pathways, these are the points that the body uses to actually regulate the flow through these pathways- major theme.2845

This is what you want to concentrate on,2861

Carnitine shuttle is the rate limiting step in fatty acid oxidation, and as such, is a point of regulation for this process, how is that?2870

OK, we are going to go ahead and stop the lesson here.2880

In the next lesson, we are actually going to talk about the actual oxidation of the fatty acid.2884

Thank you so much for joining us here at Educator.com, bye-bye.2889

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