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Raffi Hovasapian

Raffi Hovasapian

Oxidation-Reduction Reactions

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 (4)

1 answer

Last reply by: Professor Hovasapian
Mon Dec 4, 2017 1:00 AM

Post by Adrienne Purdy on December 2, 2017

Thank you so much for these wonderful videos! I was getting so confused and discouraged in class and these videos have helped immensely! Thank you for all you do!!

1 answer

Last reply by: Professor Hovasapian
Tue Jul 23, 2013 8:10 PM

Post by Gift Nitchie on July 23, 2013

For H+ + e-, can you please explain why it's not H with no charge, since they negate each other? I mean, is that the same with 1/2 H2? Thank you!

Oxidation-Reduction Reactions

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
  • Oxidation-Reduction Reactions 1:32
    • Redox Reactions
    • Example 1: Mg + Al³⁺ → Mg²⁺ + Al
    • Reduction Potential Definition
    • Reduction Potential Example
    • Organic Example
    • Review: How To Find The Oxidation States For Carbon
  • Examples: Oxidation States For Carbon 27:45
    • Example 1: Oxidation States For Carbon
    • Example 2: Oxidation States For Carbon
    • Example 3: Oxidation States For Carbon
    • Example 4: Oxidation States For Carbon
    • Example 5: Oxidation States For Carbon
    • Example 6: Oxidation States For Carbon
    • Example 7: Oxidation States For Carbon
    • Example 8: Oxidation States For Carbon
    • Example 9: Oxidation States For Carbon
  • Oxidation-Reduction Reactions, cont'd 35:22
    • More On Reduction Potential
    • Lets' Start With ∆G = ∆G°' + RTlnQ
    • Example: Oxidation Reduction Reactions

Transcription: Oxidation-Reduction Reactions

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

Today, we are going to talk about a very, very important topic: oxidation-reduction reactions.0004

In previous lessons, we have talked about ATP; we have talked about phosphoryl transfer.0010

We saw how we can take an endergonic reaction, couple it with the energy available from the hydrolysis of ATP to actually make that reaction take place.0016

We also saw that there were other molecules that have very, very high -ΔGs, and we can couple that with the ATP reaction, reverse the ATP reaction and actually form ATP.0027

The truth is that most of the ATP that is made in the body happens through a very complex oxidation-reduction process, which is essentially what metabolism is.0042

I mean, all you are doing is, you are taking in food, these highly reduced compounds, and what the body does is it oxidizes these things.0051

It takes away the high-energy electrons, and it eventually gives them to oxygen using the energy that is available; that is what produces the ATP.0060

So, directly or indirectly, whether it is some reaction that is taking place or ultimately electrons moving from reduced compounds all the way to oxygen through the electron transport chain, directly or indirectly, oxidation-reduction is responsible for all of the work that is done by the body.0070

This is a profoundly important topic; let’s go ahead and get started.0090

OK, let’s see.0096

Now, of course, you have all seen oxidation-reduction reactions; you have all had general chemistry.0100

I am going to be going through it again, sort of, from the beginning; but there are certain things that I am going to not quite touch on in as much detail.0107

I would strongly urge you to take a look at the oxidation-reductions sections of my AP chemistry course for Educator.com if certain fundamental things do not really make sense.0115

I go through a full, very complete, slow discussion with multiple examples during those lessons; but hopefully, what we do here will be enough for our purposes.0127

Redox reactions or oxidation-reduction reactions, they involve - hopefully, as you know - the loss and gain of electrons, the loss of electrons from one species and the gain of those electrons from another species, those electrons by another species; and that is it.0138

That is all that is really going on; you know, you do not want to let these sizes of the molecules scare you.0175

All that is happening is that one species is giving up electrons to another species.0181

It might pass through 5, 6, 7, 8 different intermediates, but it is still going to be something oxidized, something reduced.0186

Something loses electrons, something gains electrons.0195

During that process, hydrogens are involved; there is going to be, maybe, some rearrangements.0197

The molecules may not necessarily look the same afterward, but really, it is the electrons that we are concerned about because that is where the energy is.0202

OK, oxidation- it is the loss of the electrons.0211

Reduction is the gain of electrons.0220

Let’s just take a look at an example here, so example 1.0230

We have an equation; let me go ahead and do this in blue.0236

We have magnesium plus, let’s say it comes in contact with some aluminum ion, and it goes to magnesium ion plus aluminum.0241

When we take a look at oxidation-reduction, we are accustomed to looking at oxidation state of the particular species to decide what is being oxidized and what is being reduced.0253

In this very simple example, magnesium has a 0 oxidation state, and it has gone to a +2 oxidation state, so it has been oxidized.0261

Well, aluminum+3 to a 0, it has been reduced.0269

So, magnesium, it has been oxidized; it has lost the electrons and aluminum.0276

It has gained those particular electrons.0285

Now, of course, this is not balanced; the charges do not balance here and that is fine.0289

We will go ahead and deal with the balancing in just a second here, but the idea is something loses, something gains.0293

Now, oxidation-reductions are broken down into 2 half reactions- the oxidation reaction and the reduction reaction.0300

Let’s go ahead and deal with the oxidation here.0307

Magnesium, it turns into magnesium2+ and 2 electrons, so we represent this this way.0312

It has lost 2 electrons to become magnesium2+, and the 2 electrons are on the right-hand side.0320

Now, the reduction process, we have the aluminium ion which is 3+ has been, when you add 3 electrons to it, aluminium becomes aluminium ion, becomes aluminium metal.0326

It has gained 3 electrons; now, we need to balance this, and in order to balance this, we need to cancel the electrons on both sides and then add the equations.0343

In this particular case, we have 2 electrons, 3 electrons.0354

We multiply this equation by 3, this by 2, to convert this to - let me go ahead and do this in red - we have 3Mg goes to 3Mg2+ + 6 electrons.0357

And over here, this one becomes 2Al + 6 electrons, goes to 2 A - I am sorry - Al3 + 2Al metal.0374

And now, the electrons cancel, and when you add this straight down, you get the final balanced equation.0385

You get 3Mg + 2Al3+ goes to 3Mg2+ + 2Al metal- that is it.0393

This is pretty much how all oxidation-reduction reactions are dealt with.0406

Individual half reactions- that is all that is happening there.0410

OK, now, pictorially, what is happening is the following.0415

Should I do this on this...yes, it is fine; I can go ahead and do it on this page.0419

So pictorially, what is happening is the following.0422

You have a magnesium; you have a magnesium, and you have a magnesium.0427

Now, this magnesium has, of course, 2 valence electrons on each one, and you also have an aluminum3+ and an aluminium3+.0432

Well, this does not have any electrons on it; what happens is the following.0442

This aluminium takes that electron, takes that electron, takes that electron; and this aluminium takes that electron, that electron and that electron.0447

It takes it, or magnesium gives it up just depending on your perspective because the aluminium ion has a greater affinity for the electrons than the magnesium does.0457

In a battle of the electrons, it is the aluminium ion that is going to win; and what you end up with is, of course, the magnesium ion, which is now, completely stripped off its electrons, and you have the 2 Als that now, have the 3 electrons.0469

6 electrons are lost from the 3 magnesiums; 6 electrons are gained by the 2 aluminiums- that is it.0470

This is a simple, direct transfer of electrons from one species to another.0477

OK, now, let’s examine this a little bit.0483

Now, when we wrote this equation, when we wrote this down, when we wrote this equation, the magnesium, the aluminium, we wrote it as a foregone conclusion.0487

In other words, we wrote it as if we knew what was going to happen.0534

Well, let’s examine this a little bit.0538

But, what if we had said the following?0543

Instead of writing the equation down, if we had just told you a solution of aluminium chloride is poured onto magnesium dust, how do we know what will happen?0557

How is it that the aluminium will actually pull electrons from the magnesium metal and turn into aluminium metal itself, turning the magnesium metal into magnesium ion?0579

How do we know this, OK, or what if we had said this?0589

OK, what if we had said a solution of magnesium chloride is poured onto aluminium dust?0600

Well, now, it is the magnesium that is in ionized form, and it is being poured onto aluminium dust.0624

Now, it is the aluminium that actually has the electrons; it is the magnesium that is missing the electrons.0631

Are we able to say that magnesium is going to pull electrons from the aluminium and turn into magnesium itself, or what is going to happen?0635

How do we know this?0643

That is the whole point.0644

How do we know what will happen?0645

OK, here is how we know what will happen- something called reduction potential.0647

And you will see reduction potential listed in things called “a table of reduction potential for all kinds of species”.0658

OK, so what is a reduction potential?0664

OK, this is a quantitative - so it is a number - quantitative measure of the extent to which a given species wants to be reduced, wants to gain electrons.0668

It is a quantitative measure of the extent to which a given species wants to gain electrons- that is what a reduction potential is.0708

Now, when we measure things in science, we do not measure them absolutely.0718

We measure them relative to a standard.0724

So, when I say that a certain species has a reduction potential of, let’s say, 0.5V - and we will talk about the unit in just a minute - well, it is 0.5V relative to what?0728

OK, we need a standard reaction that we measure all of the other reactions relative to that.0739

If we have this one thing, and if we measure the reduction potentials of 50 things, it is all going to be relative to this one thing that we have chosen as our standard, as our 0 reduction potential.0749

Then, what we can do is, now that we have that list of reduction potentials, now, we can compare them among each other because they are all relative to a standard.0761

Because they are relative to a standard, they are relative to each other- that is what is going on.0770

We have chosen the following reaction as our standard reduction potential.0774

Let’s see; it is H+ + 1 electron goes to 1/2 H2.0780

You can multiply this by 2; it does not matter.0790

It does not change anything.0791

The symbol for reduction potential is this E, and this is the standard that is set at 0V.0794

OK, and a volt is a Joule per Coulomb.0801

OK, so relative to this reaction, all of the other species, the reduction potentials are measured relative to this.0811

OK, for example, in the case of our magnesium, so Mg2+ + 2 electrons goes to magnesium metal.0818

And in a table of reduction potentials, what you will see is this -2.37V.0832

OK, now, again, reduction potential, we had to choose either a reduction direction or an oxidation direction.0841

We chose the reduction so that we have a standard by which to measure everything.0850

What this means is that if I put these species, the magnesium, metal magnesium ion, hydrogen ion, hydrogen gas, if I put them in the vicinity of each other because 0 is higher, is more positive than -2.37, that means that this H+ will actually take electrons from the magnesium.0855

That means this has a higher reduction potential than the magnesium ion does.0880

So, in a competition for electrons, it is the hydrogen ion that will actually win the battle- that is what this means.0885

The numbers, the higher the reduction potential, that means it has a greater affinity for any electron that happens to be in the vicinity, and usually, the electron that happens to be in the vicinity is going to come from the other species if that species has electrons to give up- that is what is going on.0892

Now, in the case of aluminium, the aluminium is listed like this; again, they are all listed as terms of reductions.0909

There will always be some species on the left plus the electrons on the left plus any other species, but it is always the electrons on the left that are written as reduction potentials.0915

3 electrons goes to Al, and this one is listed as -1.66V- there you go.0926

Now, when you look at this, when you see magnesium ion, the reduction potential for magnesium ion is -2.37.0939

The reduction potential for aluminium ion is -1.66.0948

Well, the -1.66 is higher than the -2.37, which means that in a competition for electrons, the aluminium ion will win.0953

When you put aluminium ion, aluminium magnesium ion, magnesium together, aluminium will actually take electrons from magnesium, not the other way around.0963

That is how we know what will happen.0974

There we go; let’s write this out.0979

In a completion for electrons, the species with the more positive - and we say more positive because as you see, you can have 2 negative potentials, but relative to each other, one of them is more positive - with the more positive reduction potential, it will reduce, thereby reversing the other reaction - that is what is important - causing that species to oxidize.0982

So, going back to the question, if I had a solution of aluminium chloride, which I know is aluminium ion, and if I poured that onto magnesium dust, well, the reduction potential, looking at that, it tells me that in a completion for electron, aluminium ion will take electrons from any species that has the electrons to give.1049

Well, since magnesium is in metallic form, and it has 2 valence electrons, in this particular case, the reduction of aluminium stays as written.1071

That stays like this; let me go to blue.1081

Al3+ + 3 electrons goes to aluminium.1086

OK, and we said that the E for that is -1.66.1091

And because now, we know that the magnesium, it is going to take from the magnesium, so magnesium is going to be oxidized.1097

We reverse that reaction; instead of writing it as magnesium + 2 electrons, goes magnesium ion + 2 electrons goes to magnesium metal, we switch that around, and we write it this way.1104

Magnesium goes to magnesium ion + 2 electrons, and in the process of switching it, we also reverse the potential, so now, it is +2.37.1117

That is how we know; we take a look at the reduction potential, the one that has the more positive reduction potential.1130

We leave that one alone, and the other reaction we flip.1137

Once we flip it, then we go through the process of actually balancing that reaction, and when you balance it and you add everything, then you just add the individual potentials to get the final potential of the complete oxidation-reduction reaction.1140

Once we balance this - right, we multiply this by 2, we multiply this by 3, we cancel the electrons - we ended up with the following equation.1155

2Al3+ + 3Mg goes to 2Al + 3Mg2+.1165

And the potential for that is equal to +0.71V, and I hope that you will confirm the arithmetic for me.1179

OK, this is how we know what will happen if we are not told explicitly what will happen, and oftentime a reaction will be written in such a way, but when you look at the reduction potentials, it is actually going in the reverse direction.1189

This reaction, if you put aluminum ion together with magnesium metal, it will spontaneously move in this direction.1203

That is what this positive total net, this is the reduction; this is the potential.1210

This is the electrical potential for this particular oxidation-reduction reaction.1219

This is the complete reaction; each half reaction has a reduction potential.1224

You decide which one is going to oxidize, which one is going to reduce; you balance the equation.1228

This is our final equation; because this is positive, this reaction will happen spontaneously.1232

Electrons will flow spontaneously without you doing anything from the magnesium to the aluminum ion- that is what is happening here.1238

OK, now, in the case of the magnesium chloride solution being poured onto aluminum dust, magnesium chloride solution and aluminum dust, well, in this particular case, it is the magnesium that is in ionized form, and it is the aluminum now, that actually has - it is in metallic form - it has its electrons.1247

Well, based on the reduction potential, magnesium ion has a -2.37 reduction potential.1277

Aluminum ion has a -1.66.1287

Magnesium ion is not strong enough to actually pull electrons off of the aluminum.1292

So, in this particular case, nothing will happen; absolutely, a reaction will not take place.1298

We can write it down, but just because we can write it down, it does not mean that it will happen.1304

The reduction potential tells us so; magnesium ion is not strong enough to actually pull electrons from the aluminum.1307

That is what is going on here, and it is this is reduction potential that tells us what will happen and what will not happen.1315

OK, here we go; let’s see.1322

Let’s go ahead and look at an organic example now; that is what is going to be important.1327

Let me go ahead and go back to black ink; let me actually start this on another page.1332

OK, well, that is fine; I guess I can go ahead and start here, and then we can continue.1345

Let’s look at an organic example.1349

OK, let’s start off with…well, that is fine.1360

Let’s go ahead and do RC, OH + Cu2+, goes to RC double bond, OOH + Cu2O.1365

OK, in this particular case, we have a couple of things going on.1381

Now, first of all, we have to decide which one is being oxidized and which one is being reduced.1386

Here, we have this aldehyde and we have copper ion.1392

Well, the oxidation state of copper is +2; and over here, oxygen is a -2.1396

There are 2 coppers, so that means, now, the individual copper is in oxidation state of +1.1402

And again, if this idea of assigning oxidation state is still a little hazy for you, by all means, please take a look at the sections in the AP chemistry course under oxidation reduction where I go very, very carefully through this process.1408

It looks like the copper is reduced, which means the carbon is oxidized.1422

Here, we have an oxidation state of +1 on this carbon, and here we have an oxidation state of +3 on this carbon.1427

Now, of course, this is not balanced; but we are not concerned with the balancing, right now.1435

We are just concerned with recognizing what is oxidized and what is reduced.1440

So, carbon is oxidized; copper is reduced.1443

OK, now, let’s go ahead and take a moment to review how we actually find the oxidation states for carbon.1448

I will start that over there; let’s review...oops, there we go.1458

Let’s review how to find the oxidations states for carbon.1469

OK, we start off; for a given carbon, start with an oxidation state of 0.1486

Now, there are different ways to actually represent the oxidation state of carbon.1504

You can go from 0 to 8; you can go from -4 to +4.1508

Again, it is just depends on what you are looking at, in terms of how many electrons that particular carbon owns.1515

That is what oxidation state is; it is a measure.1522

It is a statement, a numerical measure of how many electrons it actually has, that it, actually - you can say - that it owns.1525

The range itself, the specific numbers do not really matter.1533

What matter is what is going on chemically.1537

I would like 0 because I think it is a great way to start.1540

You can sort of see from 0 the gain of electrons, the loss of electrons, so I have chosen that as my standard.1544

I am going to go up and down from there as opposed to, say, 0-8.1552

It is just depends on what particular book you are using, what your teachers teaching you; but hopefully, this will make sense.1556

So, no. 1, OK, for every bond - when you are looking at a given molecule for a given carbon - for every bond to another carbon, there is no change in oxidation state.1564

No. 2, for every bond to hydrogen - and this is actually very, very easy - you add a -1 or subtract 1, depending on how you want to.1589

I think of it as adding a -1 because you are adding an electron.1606

So, when you add a hydrogen, if you see a hydrogen bond into a carbon atom, that means that the oxidation state is...you add a -1 to it.1609

In other words, the carbon is more electronegative than the hydrogens, so the carbon owns that electron.1619

It is carrying that extra negative charge- that is what that means.1623

And, of course, the third one, for every bond to oxygen - or in parentheses, I will put or a sulphur chlorine, basically anything that is more electronegative than carbon etc., but mostly it is going to be oxygen - you add a +1.1627

What that means is that it has lost ownership of that electron; the oxygen or the sulphur or the chlorine has taken the electron away from the carbon.1652

Let’s just do a bunch of examples, go through the range of oxidation states for carbon.1659

I think this is really, really important, so examples.1662

We are going to run through the entire range here.1668

OK, so let’s start off with methane H, H, H, H.1671

We start with an oxidation state of 0, and then we said for every bond to hydrogen, we add a -1.1677

So, we have -1, -1, -1, -1; our oxidation state of methane is -41684

It is a very, very, highly reduced form of carbon; in fact, it is the most reduced form of carbon.1693

It actually owns not only its 4 electrons that it brought to the table, it has also taken away the electrons from a hydrogen.1699

It is carrying a -4 charge; this is why I chose 0.1705

I think, because it tells you how many electrons it has actually taken from other species as supposed to the total.1710

OK, well, let’s take a look at another one; let’s take a look at H3, C, C, C, C, C.1717

This is going to be ethane; we said bond it to another carbon.1728

No change, it is 0; and then 3 hydrogens here, so -1, -1, -1.1733

Now, it is -3; OK, now, the oxidation state on this carbon is a -3.1738

OK, in other words, it owns its 4 electrons and the 3 that came from hydrogen carbon-carbon bond.1747

It is equally shared, so it does not really own anything.1754

OK, let’s go ahead and do this one.1758

Let’s do H2, C, C, H, H.1764

OK, one bonded carbon, another bonded carbon, so this is going to be 0 + 0 and then 2 hydrogens - 1, -1.1770

It equals an oxidation state of -2.1780

OK, let’s try another molecule here; let’s try this H, H, OH.1784

This is ethanol; OK, bonded to carbon, that is a -0 - 1.1792

Hydrogen is -1; oxygen is +1, so you get a oxidation state of -1.1799

OK, let’s try CH3, CH3, CH3.1812

This time, we have a carbon surrounded by 4 carbons.1821

This is just 0 + 0 + 0 + 0, so the oxidation state is 0.1825

This is a nice, basic, normal, everyday carbon; it owns its 4 electrons, and that is it.1831

Nothing is lost; nothing is gained.1837

Everything is good.1839

OK, now, let’s take a look at an aldehyde, so C, H, CH3.1841

OK, this is acetaldehyde.1851

We have the carbon, which is 0; we have the 2 oxygens, so +1 +1 - not the 2 oxygens, the 2 bonds - the 2 oxygens, each bond, and then -1, we get a +1.1854

In the example that we were looking at for the oxidation-reduction, that was some sort of an aldehyde; it had an oxidation state of +11872

OK, let’s take a look at a ketone here, so C.1881

This is CH3; this is CH3.1887

We have carbon, carbon, so it is going to be 0 + 0, and then, +1 +1 for the 2 bonds to oxygen.1892

Now, it has an oxidation state of +2.1899

What that means is it brought 4 electrons to the table; it has lost 2 of those electrons to oxygen.1903

Oxygen has come; it is bound with it, and it has pulled electrons away from it.1909

I mean yes, it is still sharing; it is involved with the bond, but the electrons are with oxygen mostly, not with carbon.1913

That is what that +2 means; it has lost 2 electrons.1919

This is why I think it is best to start with a 0 because from 0, you can tell how much you have gained, how much you have lost.1923

OK, let’s take a look at a carboxylic acid here, so acetic acid.1930

This is CH3, so carbon is a 0; we have +1 and +1 for the 2 bonds to oxygen.1936

And then, we have, oh another +1 for another bond to oxygen; so this is +3.1944

In the example that we were just looking at, the oxidation by copper ion, it went from a +1 state, an aldehyde to a carboxylic acid, which was a +3 state, so it lost 2 electrons.1949

So, +3 means that it brought 4 electrons to the table; it has given up 3 of them to oxygen.1963

It has been oxidized, and let’s take a look at the final.1970

Now, of course, there are multiple variations on this, but now, we have +1, +1, +1, +1.1975

This is a +4 oxidation state; carbon brings 4 electrons to the table.1985

Oxygen has taken away 2 of them; the other oxygen has taken away 2 of them- that is it.1989

Carbon is completely oxidized at this point; when you exhale, you exhale carbon dioxide.1994

It is a waste product; all of the electrons from carbon, those high-energy electrons, have been taken away, used for other purposes.2000

Now, this carbon is completely spent; there is nothing else for it to do.2007

The range, as you see, is -4 to +4; it is those 9 oxidation states including 0.2012

Those are the oxidation states of carbon- that is it.2021

That is all that is going on here; there is certain number of electrons.2025

The body takes those high-energy electrons and uses them for other purposes- that is oxidation-reduction.2029

OK, a couple of things to notice.2035

You know what, I think I am going to write it on this page.2042

Notice how as carbon becomes more oxidized, in other words, as its oxidation state rises from negative to positive, it is losing hydrogens.2045

In biological systems, oxidation will often mean losing hydrogens.2073

Yes, you are losing electrons with those hydrogens, but the electrons usually come in the form of hydrogen, so this is going to be a very, very big deal.2080

When we think about oxidation, we think about the loss of hydrogens.2089

That is not the only way oxidation happens, but to a large extent in physiological systems, that is how it happens.2094

We think of reduction as the gain of hydrogens, gain of hydrogen atom, because the hydrogen atom brings, it has an H and an electron, an H and an electron or maybe a hydride.2100

A hydride has an H + 2 electrons.2111

So, often, oxidation reduction in biological systems will take place like this; we often look at the gain and loss of hydrogens.2114

OK, now, let’s go ahead and return, and talk a little bit more about reduction potential, say a little bit more, so back to reduction potential.2121

Now, this E with a little 0 on top is the standard reduction potential, and standard means that when we ran these experiments to actually get these numbers that we got like for the aluminium and the magnesium - well, hold on a sec, let me just go ahead and finish writing this, it is a standard reaction potential - standard, it means that when we ran these experiments, the concentrations were all 1M.2141

The temperature was 25°C, and if there was a gas involved like hydrogen gas in the reference cell, the gas was pressurized at 1 atmosphere, so standard conditions.2168

Again, a standard, we need a reference.2178

Now, but concentrations in cells are not standard.2181

So, let us introduce an equation, which gives us a way of finding the actual reduction potential of either individual species, the half reactions, of either half reactions or the potential of fully balanced reactions, where we have actually put the half reactions together to find both the oxidation and reduction, our final reaction, our net reaction, our fully balanced reaction.2200

OK, so you remember we actually did this with the ΔG.2276

We said that we have a ΔG standard, but then if the concentrations are different, it is going to change the ΔG.2280

We saw that under standard conditions, ATP -30.5kJ/mol, but under physiological conditions, it could be -50, -55, even up to -60, 65kJ/mol, depending on the concentrations.2286

Well, it is the same thing, and in fact, we are going to start with the same equation, the ΔG; but now, we are going to be talking about electrical potential because it is electrons that are moving,2300

Let’s start with that equation; let’s start with ΔG = ΔG standard + RT ln Q.2311

That is the equation we are going to start with; now, the floor of electrons does work.2327

Anytime there is some sort of oxidation-reduction process taking place, work is being done.2331

There is energy that is often released in the spontaneous process like that.2335

Now, there is a relationship: the ΔG = NF times that of the reaction.2340

So, when we have a balanced oxidation-reduction reaction that has a certain electrical potential - that is this E thing, E of the reaction - well, there is also a ΔG associated with that reaction.2349

This is the relationship between those 2; here, N is the number of electrons that are transferred, and F is the Faraday constant, and it happens to be 96,485C/mol of electrons.2359

A coulomb is a unit of charge, so in 1mol of electrons, there is 96,485 units of charge that those electrons bring.2390

OK, now, let’s go ahead sell ΔG = ΔG standard + RT ln Q.2402

ΔG also equals this; we are going to put this in where we see ΔG, so here is what you get.2412

You get minus - oh this is a negative here, sorry about that - this is -nFE = -nFE standard + RT ln Q.2419

When I divide it by -nF, I am left with the following: E = E standard - RT/ nF ln Q.2434

This equation and this equation, these are the 2 important equations concerning oxidation-reduction chemistry.2446

This is called the Nernst equation.2455

If I have a particular oxidation-reduction reaction or a half reaction and if I know its potential, I can go ahead and calculate the free energy change of that reaction.2461

If I have the standard reduction potential, which is listed in tables, and if I have concentrations that are different or temperatures that are different, I can actually calculate the new potential in order to calculate the ΔG.2471

So, these two equations are what is important; this is really what this lesson is about- these 2 equations.2486

OK, so let’s go ahead and examine these equations by means of an example; that is going to be the best thing to do.2494

Now, let’s see, example.2503

That is the best way to make sense of anything, is to do examples.2510

In the table of reduction potentials, we have the following.2514

We have...let’s see, should I write it out or should I…yes, that is fine.2537

I will go ahead and draw the structure: H3, C, C, H.2543

This is acetaldehyde + 2H+ + 2 electrons goes to…you know what, actually I am going to make this a little bit easier.2548

I am not going to draw out the structures; I am just going to go ahead and write out the words.2558

I think that is better; we have acetaldehyde + 2H+ + 2 electrons goes to ethanol, and its standard reduction potential happens to be -0.197V.2562

OK, well, we also have the following; we have something else in the table, and it says NAD+ + H+ + 2 electrons goes to NADH.2584

Now, do not worry about what NAD+ and NADH are.2598

Right now, we are actually going to be discussing that in the next lesson; for right now, it is just a species.2601

It is the oxidized version of the species in the vicinity of a couple of electrons.2607

When it becomes reduced, it turns into this thing called NADH, and it has a reduction potential relative to the reference hydrogen electrode, and its reduction potential is the following.2612

These are -0.320.2626

Now, the question is “what happens when these species are brought in to contact with each other?”.2633

“When I have some acetaldehyde, some ethanol, some NAD+ and some NADH, what is going to happen?”.2637

Well, take a look at the reduction potentials; this is -0.197, and this is a -0.320.2644

This one is actually more positive than this one, so this will end up staying as written.2651

The acetaldehyde will reduce to ethanol; this one will end up having to reverse.2657

It is going to end up being the NADH; that is going to end up turning into NAD+.2662

Acetaldehyde will reduce, NADH will end up oxidizing- that is what is going to happen.2668

Well, the E of the acetaldehyde is greater than the E standard of the NAD+, so the NAD+ reaction gets reversed always- that is what we do.2679

Under spontaneous conditions, these numbers tell us that is what happens - gets reversed - so what we end up with is the following.2701

Let’s see; we end up with acetaldehyde + QH+ + 2 electrons goes to ethanol, and its standard is -0.197; and the other one gets reversed.2711

So, we write it as NADH goes to NAD+ + H+ + 2 electrons.2733

And because we reversed it, we actually end up writing it as now, a +0.320.2745

We go ahead and we cancel electrons; in this case, there is 2 here and 2 here.2753

We do not have to multiply it by anything to balance it.2758

We cancel this H+ with one of those H+s, and what we are left with is the net reaction.2760

Acetaldehyde reacts with this thing NADH under some slightly acidic conditions, and it turns into ethanol; and it releases NAD+.2766

The net for this, just add this and this; and what you end up with is +0.123- that is all we have done.2789

Aldehyde and ethanol, if you put them together with NAD+ and NADH spontaneously, what is going to happen is the aldehyde will react with the NADH.2802

The aldehyde will reduce the ethanol; the NADH will become oxidized to NAD+; and this is the measure of the extent to how fast it is going to go.2813

Now that I have this, I can actually calculate the free energy change for this based on the equation that I have got.2824

Now that I have this, my free energy change for this reaction is -nFE of the reaction.2831

It equals minus, well, N is the number of electrons that is transferred.2843

We have 2 electrons that are transferred; let me actually write here: 2 moles of electrons are transferred.2848

We have 96,485C/mol of electrons.2857

And, of course, we have the potential, which is +0.123V, which is a Joule per Coulomb - and I just wanted you to see that the units cancel - and when you multiply all this out, you get a ΔG for this reaction, is equal to -23,735J.2868

There you go; that is it.2883

That is all that is going on here.2886

We have some species; we have a table of reduction potential.2888

We have some species; its reduction potential is this.2892

We have another species; its reduction potential is this.2894

Under conditions when these things are brought together, what is going to happen spontaneously - well, spontaneously because this is larger than this - it is going to reverse the other one to induce, it is going to flip it around.2898

This will stay a reduction; this will become an oxidation.2909

We go ahead and write it; we cancel electrons.2913

We get the final balanced equation, so this is the reaction that is going to take place.2916

This reaction will take place spontaneously; we do not have to do anything.2921

It does not mean the reverse reaction will not take place because the reverse reaction does take place.2926

Enzymatically, it can happen; but spontaneously, this is what will happen; and this positive potential tells us that that will happen.2932

This reaction as written, because of this equation, actually gives us the free energy change.2959

Notice, -23.7kJ- that is a very, very highly exergonic reaction.2965

This reaction wants to go forward; that is all that is happening here.2973

OK, thank you for joining us here at Educator.com.2977

We will continue our discussion of oxidation-reduction chemistry in the next lesson; take care, bye-bye.2980

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