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Raffi Hovasapian

Raffi Hovasapian

More Example Problems with Carbohydrates

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 (7)

1 answer

Last reply by: Professor Hovasapian
Thu Oct 19, 2017 5:35 AM

Post by Maryam Fayyazi on October 17, 2017

Thanks for amazing lecture. I was wondering if we can have a lecture on DNA, RNA as well

2 answers

Last reply by: David Gonzalez
Sat Aug 9, 2014 3:24 PM

Post by David Gonzalez on August 7, 2014

Hi professor Hovasapian. As always, great lecture!

I have a semi-related question that I hope you can help me with: what's the best way to gain lab experience (in cell biology/biochemistry) if I'm not going to school? Within the next few years, I'm hoping to have learned enough to start a lab (lofty goal, I know) that deals specifically with diseases of old age.

I'm really dead set on this goal, and have been pushing myself through 8-hour study days (with the help of tutors, textbooks, and online resources like Educator.com) for the past year! Do you think that there are universities/colleges that would allow me to "intern" there for the sake of learning, even though I don't have a degree?

I really appreciate you taking the time to read this professor.

0 answers

Post by Professor Hovasapian on October 31, 2013

Hi Marvin.

I hope you're well.

I decided to skip it because, in most places, a separate class (Molecular Biology) deals exclusively with all aspects of Nucleic Acids. However, many people take only a Bochemistry...or perhaps people take this course without being formally enrolled in a course at a Uni anywhere. It would be a shame for these people to be short-changed vital info on Nucleic Acids.

I'm hoping to remedy the situation by recording an entire Unit on Nucleic Acids in the future, and adding it to this Biochem course.

I apologize for the inconvenience.

Raffi

0 answers

Post by Marvin Alashker on October 31, 2013

is there a reason you skipped the chapter on nucleic acid?

More Example Problems with Carbohydrates

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
  • Example 1 1:09
  • Example 2 2:34
  • Example 3 5:12
  • Example 4 16:19
    • Question
    • Solution
  • Example 5 24:18
    • Question
    • Structure of 2,3-Di-O-Methylglucose
    • Part A
    • Part B

Transcription: More Example Problems with Carbohydrates

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

Today we are going to round out our discussion of carbohydrates by just doing some more example problems with them.0004

If you feel comfortable with it, it is not a problem; you can move on to the next lesson, but I thought it would be nice to sort of recap, and maybe towards the end do something a little bit more complex.0010

Let’s get started.0019

Pretty basic stuff, again, we are mostly concerned with structure.0022

The idea behind carbohydrates is you want to be able to recognize the monomers, recognize the connections of the glycosidic bonds and be able to sort of put, not sort of, be able to put them together; or given a structure, be able to say that "this is this connection, this is this connection".0025

That is really the main purpose; we want you to have a good structural understanding of what is happening with the carbohydrates.0043

The rest of the information is information, the extent to which the level of detail that you need regarding the function of a particular family of carbohydrates over a specific carbohydrate, that is going to depend on what your teacher wants, how much he or she wants you to know.0049

It is structure that we are ultimately concerned with.0066

OK, example no. 1.0069

Let’s go to blue; I like blue.0073

So, example no. 1: draw the linear form of D-ribose.0080

OK, linear form; we are not putting it in a ring.0093

Ribose is going to be a 5 carbon sugar, and it isn't aldose.0098

It has an aldehyde on the no. 1 carbon, not the ketose, which would be a ketone on the no. 2 carbon.0103

Let’s just go ahead and draw our carbon chain; this is 1, 2, 3, 4, 5.0109

Let’s go ahead and put our aldehyde group up there.0116

Let’s go ahead and put the H2OH, the non-chiral carbon and as far as ribose is concerned, ribose happens to have all hydroxys on the right- that is it.0119

This is D-ribose, and notice there is no alpha-beta here because it is not in a ring formation.0130

That alpha-beta only refers to when a particular sugar is in a ring formation and whether the hydroxy is pointing below the ring, alpha or above the ring, beta when you are looking at it in a standard projection with the oxygen in the back right or in the case of a pentose ring, with the oxygen straight back- that is it, nice and simple.0135

OK, example no. 2.0155

Oops, go ahead and do this, example 2.0160

Xylose is a c2-epimer or epimer depending on how you want to pronounce it.0167

It is completely up to you; pronunciation is completely irrelevant unless people really just absolutely don not understand what you are saying- epimer of D-ribose.0175

Oh, and again, the D part, this D versus L, that comes from the chiral carbon that is farthest from the aldehyde; that is this one.0189

D, the hydroxy is on the right in linear form like this, in Fischer projection.0200

If it were an L-ribose, the hydroxy would be on the left, so this specifies the D.0205

OK, xylose is a c2-epimer of D-ribose.0212

Draw its linear structure; draw its linear structure.0216

Well, nice and easy.0222

We know that an epimer just means that at that particular carbon, in this case, the no. 2 carbon, the configuration is switched.0225

So, when we want to switch a configuration, we switch to the substituents.0232

In other words, we just move the OH from one side to the other.0236

I mean obviously over here we have hydrogens; we have not put them in here for the...but they are there.0240

In general, I will leave the hydrogens off.0244

OK, let’s go ahead and draw the structure again, 5 carbons, 1, 2, 3, 4 and 5; and we will go ahead and put our aldehyde.0249

Oops, excuse me; let’s make this a little bit better.0260

That is that; that is the hydrogen.0263

That is our aldehyde group; let’s go ahead and put our H2OH, the non-chiral carbon, so c2-epimer.0265

This is 1; this is 2.0271

This is 3; this is 4.0273

This is 5, so 1, 2...wait, I am sorry.0275

Xylose is a c3-epimer, my apologies.0282

I was going to say something is going on here, so 1, 2.0287

The 2 hydroxy stays the same; that is on the right.0289

c3-epimer, this is the one that goes on the left, and this is that, so there you go.0294

That is xylose, the c3-epimer of D-ribose.0300

No. 3 carbon just switched the configuration- that is all.0305

OK, let’s see; let’s draw some rings here.0308

Example no.3: draw the furanose and pyranose forms of D-xylose.0316

We just had the linear form of D-xylose.0338

Now, what we want to do is they want us to draw the ring configuration, but they are not specifying, well, they are telling me that they want both ring configurations.0340

They want the 5-membered ring, the furanose; let me go ahead and do this in red.0349

The furanose is the 5-membered ring, and pyranose is the 6-membered ring.0353

We are going to take a look at the structure to see which hydroxys we are going to attach to the aldehyde carbon to create the 5 and 6-membered ring.0358

And again, sugars, they can form 5-membered rings, 6-memembered rings, any of the hydroxys because sugars have hydroxys in all of the carbons- any of them can react.0369

So, if they can form a stable ring, they will, sometimes 5-membered, sometimes 6-membered.0377

Now, obviously, there are going to be certain rings that are going to predominate, but in this particular case, you can actually have both.0382

Let’s go ahead and draw our linear structure again; let’s go through our systematic procedure, and it is always best to do this.0390

We have 1, 2, 3, 4 and 5.0396

This is our aldehyde, and we had the hydroxy on the right, hydroxy on the left, hydroxy on the right and our achiral carbon, so that is that.0402

Now, let’s go ahead and do the furanose form first; furanose means 5-membered ring.0412

Well this is 1 carbon; Let’s do this in black.0419

This is no. 1; this is no. 2.0424

This is no. 3; this is no. 4.0428

We got an O to react with that, so I am going to go over here.0431

This is going to be no. 5.0434

OK, in our ring, this oxygen is what is going to attack that.0436

We have to know which oxygen is going to happen.0444

When we do the pyranose in a minute, it is actually going to be this oxygen right here, down below.0447

It is going to look completely different, but it is going to be the same sugar but in a completely different form.0452

OK, what we do next is we rotate this to the right, the top; we bring it down to the right.0459

Let’s go ahead and draw that configuration.0465

Let me see, should I do it...I’ll do it over here, a little higher up, so we have plenty of rooms.0470

1, 2, 3, 4 and 5, now, I have my aldehyde here, and this drops down.0473

This hydroxy goes up; this goes down, and here I will just write it as CH2OH.0483

That is this one right here.0490

Now that I have it in a horizontal fashion, I take the left hand side and I pull it.0492

I push it away from me, and I bring it around.0497

Now, let me draw this; when I do that, I have this.0500

Let me see, make sure I have enough room here.0506

C, C, this is my aldehyde; I have a C here.0509

I have a C here, and I have a CH2OH.0515

So, make sure 1, 2, 3, 4, 5- that is correct; and let me see, on the 2, 1, 2, this hydroxy is down.0522

This hydroxy is up, and this hydroxy is down.0530

OK, we said that this hydroxy on the no. 4 carbon, this one right here, that is the one that is going to react.0535

That is the one that is going to attack the carbonyl, so what we want to do is rotate 90° upward just like this.0540

In the back, this group right here in the back is like that.0552

This is the OH; we want to rotate it like this to put the OH horizontal just so we know where this thing ends up.0556

Let’s go ahead and do that; this is going to go, let me go back to black.0565

OK, now, I am going to redraw this structure with this back group rotated 90° up and just to make the OH horizontal, just to be consistent.0572

We are going to have C, C, C, C; actually you know what, let me make it a little bit lower here.0582

I have got C, C, C, C, and now, I have my OH there; and now, I have my CH2OH here.0595

This is the oxygen; let me finish by drawing in my carbonyl.0606

This is the oxygen that is going to actually attack; this is what is going to attack from above or from below in order to get the alpha-beta.0611

Here is what happens, when that happens, and now, I will go ahead and put equilibrium arrows because the ring structure and the linear structure, there is going to be an equilibrium between those two and here is how it works.0623

We have 1, 2, 3, 4, 5; let me confirm, and, of course, a 5 carbon.0635

We put the oxygen in the back, and I decided not to put the carbons in.0640

I hope you don not mind; I will do...actually you know what, maybe I will.0646

This is O; that goes there.0655

That goes there; this goes there.0657

This goes there, something like that.0659

Now, over here, we are going to have the...I am going to not specify the stereochemistry on that.0662

It could be alpha-beta depending on whether its attack from above or attack from below, but here, no. 2 carbon, the hydroxy is down below the ring.0667

The no. 3 carbon, the hydroxy is above the ring, and, of course, here we have our CH2OH group.0676

There you go; this is D-xylofuranose.0683

Take a good look at this because it is going to look nothing like the D-xylopyranose.0691

Unspecified stereochemistry could be alpha or beta, but these are...they are definitely specified.0698

This is below the ring; this is above the ring, and you have that.0703

This is the no. 1 carbon, just a number 1, 2, 3, 4, 5 carbon 1, 2, 3, 4.0708

This is the fifth member of the ring- that is it.0718

We have to know which oxygen we are using, attached to which carbon, is actually going to form it.0721

This is why it is important to go through the systematic procedure- do this, do this, decide which is what.0727

In a minute, we will see we do not actually have to go through the rotation here when we do the pyranose form- this is it.0733

This is D-xylofuranose; This is the 5-membered ring.0739

OK, now, let’s go ahead and do our D-xylopyranose form.0743

OK, let me go back to blue, and let me start with the third structure that I drew.0749

I had the linear; I turned it around, and I brought that back.0759

Let me start with that; I have got, let me see...a little bit lower here.0761

I have got C, C; now, let me put the carbon backbone in first, C and CH2OH.0770

Let me put my aldehyde in; I have got down below.0779

I have got above the ring, and I have got this.0784

Now, I do not have to do anything to this; now, I need a 6-membered ring, the pyranose form.0788

That means that 3, 4, 5, my sixth member of the ring is this oxygen.0794

It is this oxygen that is going to attack this carbon either from above or from below.0806

Now, nothing changes over here; this hydroxy is going to stay down below, and you are going to get a 6-membered ring.0813

Now, for a 6-membered ring, of course - excuse me - the standard position is oxygen in the back right.0819

Let me go ahead and draw that; so, we have this, this, this, that, that and that.0827

Now, let’s go ahead and see what it is that we have; again, we are going to not specify the stereochemistry that can be alpha or beta, depending on attack above or below.0834

Remember, that is the no. 1 carbon; OK, the no.1 carbon.0844

On the 2 carbon - let me go back to red - the hydroxy is down.0847

On the no. 3 carbon, the hydroxy is up; on the no. 4 carbon, the hydroxy is...wait, where am I?0852

1, 2, 3, 4, 1, 2, see, now, I am getting confused, alright.0864

We have got, on the second carbon, that is down; that is up, and this is down.0871

There we go; that is the no. 4 carbon, and over here, there is nothing at all.0880

As you can see, it is easy to lose your way here.0885

So 1, down the 2, 3 and 4, that is...let me see, this is blue.0888

This is 2; this is 3 and this is 4- good, everything is good.0894

On the 5 carbon, you just have 2 hydrogens; I will leave those hydrogens off- that is it.0898

This is the D-xylopyranose; it looks nothing like the D-xylofuranose.0903

It is just a question of keeping track of which hydroxys go where, what the arrangement is, and that is it- just nice, systematic, but as you can see, you have to be really careful because it is easy to lose your way.0912

OK, let’s see.0925

I have anything, and once again, take note of the fact that this no. 5 carbon, because it is a 5 carbon sugar in the pyranose form, it is forming a 6-membered ring.0932

This carbon, the no. 5 carbon, it does not have anything on it.0943

You are used to seeing something on it either a CH2OH, either above or below, because you are so used to seeing galactose.0948

Well, you are used to seeing glucose, galactose, mannose, things like that, but again, different sugars have different things that are attached to them.0955

In this particular case, you have not missed anything; it is just 2 hydrogens that are attached there, so you are good.0962

OK, well, let’s see; let’s move on to example no. 4.0969

OK, this one is a little longer, so instead of writing it out by hand, I thought I would just present it like this.0980

A biochemist wants to synthesize a new branched polysaccharide.0986

It is an amylose chain with branching at the no. 6 carbon.0992

So, you remember, amylose is the glucose monomers; it is a homopolysaccharide.0997

It has a bunch of glucose monomers that are attached by alpha-(1,4) linkages.1002

There is going to be branching at the no. 6 of one of those glucose.1009

OK, now, the first monomer at the branch point will be the furanose form of alpha-D-xylose- we just did that.1013

The rest of the branch alternates between monomers of alpha-D-xylose and N-acetylglucosamine in the following configuration: GlcNAc-alpha-(1,3)-xylose.1021

The Glc, the N-acetylglucosamine, is connected via alpha-1, and it is connected to the no. 3 carbon of xylose in the glycosidic bond.1033

We want you to draw the structure.1044

OK, basically, real quickly, just to get a sense of what is going on, so we are going to have this amylose chain, just these glucose monomers, again I am just doing a quick schematic before I...so, that, that, that.1046

Let me just draw 4 of them; that is going to be the alpha-(1,4) of the glucose- not a problem.1064

And, let me just actually draw one more, and at the no. 6 carbon of one of those, it is going to be something like that; and it is going to be O, and it is going to be connected.1069

The first monomer of the branch point will be the furanose form of alpha-D-xylose, furanose form, so this is going to be a 5-membered ring, here.1081

Let me just go ahead and just do a little square like that.1092

It is going to be a 5-membered ring, and it is going to alternate between monomers of alpha-D-xylose and N-acetylglucosamine.1095

Let me do a little triangle for N-acetylglucosamine, a square for xylose, a triangle for N-acetylglucosamine.1102

This is what is going to happen; we have glucose monomers making up this chain.1110

At a branch point no. 6, we are going to have in alpha-D-xylose; and then we are going to alternate alpha-D-xylose, GlcNAc, Xyl, GlcNAc.1115

That is what we want to draw.1126

OK, hopefully, we either know; we have either memorized the monomer’s structure, or we just open up our books or look on the internet to get the particular monomer’s structure, and then we just construct our molecule and just remembering that it is alpha-(1,3) in the GlcNAc-xyl glycosidic bond.1127

OK, let me do this one in red; let me see here.1148

I think I will do it on - oops - I think I will do it on the next page.1153

OK, OK, so let’s go ahead and draw our alpha-(1,4)-glucose.1161

Let’s draw out 3 of those; let’s go like that.1166

Let me just go ahead and draw my...so, this is alpha-(1,4)- there we go.1174

Now, let me go ahead and put in my CH2OH.1190

Let me go ahead and draw everything in, and then I will go ahead and talk about it.1202

OH, OH, and this is down below already; that is connected on a glycosidic bond, so we have got CH2.1208

OK, now, I am going to go ahead and connect this one, so I will do a CH2 here.1219

This is my no. 6 carbon; 1, 2, 3, 4, 5, 6, my no. 6 carbon.1224

This is the one that is going to be connected, oxygen; and this is what is going to be connected here.1235

Now, I am going to have a 5-membered ring; well, my 5-membered ring, let me make this...that is OK.1243

I do not have to make it too long; my 5-membered ring is going to look like this.1251

Bam, bam, bam, bam, and, of course, here, we have our oxygen; and then this is xylose, so that is OH there.1255

Let me go ahead and put my CH2OH here.1265

Now they said that it is going to be a 1,3 glycosidic bond with the next monomer, which is the N-acetylglucosamine.1270

I’m going to go ahead and draw this way, O; and now, I will draw in the N-acetylglucosamine.1277

This is N; this is COO.1291

This is CH3; this is OH, and, of course, this is going to be O, and this is going to be alternate with that.1295

So, we have another 5-membered ring.1307

This is OH; this is going to be CH2OH, and this is going to be another O connected to something else.1312

Let’s make sure that I have got everything that I am supposed to have here.1322

This right here...I apologize; I lost my colors.1327

This right here is our Glc-alpha-(1,4)-Glc.1334

This is our main; here is a branching point at carbon no. 6.1344

The first monomer is alpha-D-xylose; this is the alpha-1.1350

This is the alpha connection; this is the xylose ring.1355

And, we said that we have a GlcNAc, N-acetylglucosamine in alpha-(1,3) to xylose-alpha-(1,3).1361

This is the no. 3 carbon; OK, this is connected that way.1380

Then, of course, this goes to another; OK, this connection right here, that is going to be xylose-alpha-(1,4)-GlcNAc.1386

So, if you want you can sort of connect this to this one; actually, let me write it right next to it.1405

Because we are alternating monomers, we have to specify at least 3 of them.1410

So, GlcNAc, this is going to be 4; this is going to be alpha-1, and this is going to be Xyl.1415

Xylose-alpha-(1,4)-glucoseNAc, at the other end of the glucose, the reducing end, that is going to be alpha-(1,3) to the xylose and so on, so xyl-GlcNAc, xyl-GlcNAc this way- that is it.1423

That is our structure; everything is taken care of.1437

All the stereochemistry is represented, the connection, 1,6 branch point, 1,3, alpha-(1,4), here- there you go.1441

That is our polysaccharide.1452

OK, good.1456

OK, now, let’s do example 5.1459

OK, example 5 is a little long in terms of just actually writing it out as far as what is going on, but it is not altogether that difficult.1464

This is a great practice in structures, and it is a great practice on actually handling a carbohydrate, how one deals with finding out certain things about it.1473

OK, now, a biochemist wants to determine the extent of branching in a sample of glycogen.1482

So, we remember glycogen molecule, it has a whole bunch of branching.1489

It is just like the starch, except it is more heavily branched and it is more compact, consists of amylose and amylopectin with 1,4 connections and then 1,6 branching at the no. 6 carbon like we just did.1492

OK, a biochemist wants to determine the extent of branching in a sample of glycogen.1509

The branching takes place on those glucose monomers that have their no. 6 carbon and hydrogen attached.1524

A certain number of those glucose monomers have branching at the alpha-(1,6).1531

We want to know what percentage of those, so mind you, we are not saying what percentage by mass.1538

We are saying what percentage, which means we are talking about number.1543

So, of let’s say, 5,000 monomers that make up some glycogen molecule, how many of those 5,000 are actually monomers of glucose that have a 1,6 branch- that is what we are asking.1548

OK, here is what he does.1560

He takes the glycogen and he treats the sample with methyl iodide in order to methylate any free hydroxy groups.1563

That means, I am going to turn the OH groups, the free hydroxy groups in glycogen into OCH3 groups.1569

I am just converting them into, I am just adding a methyl group; I am replacing this hydrogen with a CH3.1578

OK, he then completely hydrolyzes the glycogen to release the free monomers.1584

So, once I convert the free OHs to OCH3, I split up every single glycosidic bond, and I have a bunch of monomers floating around.1589

He measures the amount of (2,3)-Di-O-methyl-glucose recovered, and he makes his computation.1598

OK, the structure of (2,3)-Di-O-methyl-glucose is as follows.1608

We will draw our regular hexose ring, Di-(2,3), (2,3)-Di-O-methyl.1614

Let’s go ahead and specify; let’s just not specify it.1625

We do not have to do that; that is not important.1628

Normally, we have OH, OH, OH and CH2OH, right?1631

Di-O-methyl, (2,3)-Di-O-methyl, well, this is the no. 1 carbon, no. 2, no. 3.1641

All we have done is replace this with CH3 groups.1647

This is the molecule (2,3)-Di-O-methyl-glucose.1654

So, he methylates the glycogen; he completely hydrolyzes it to release all of the free monomers.1657

Now, remember hydrolysis, elements of water, you are splitting it up while you are adding the elements of water, splitting it up the glycosidic bonds.1663

And, what he recovers, he recovers this molecule, and he measures this molecule, the amount that he has of this molecule to determine what percentage are actually branched.1673

OK, now, let’s go ahead and see what we can do, explaining detail, what is happening in this procedure using structures.1688

OK, let’s go ahead and draw a structure, and let’s talk about what it is that is actually going on.1698

OK, let’s draw a linear; let’s draw a part of this molecule.1704

I will draw it a little bit smaller than usual just so I have room on this same page.1716

OK, boom, boom, boom.1724

OK, I will go ahead and do that, and now, let me go ahead and draw my OHs in.1728

So this goes on that way, and this goes on that way; now, there is going to be a branch point.1733

This is going to be CH2, and that is going to be O, and that is going to be like that; and, of course, it is going to go on, it is going to repeat that way.1739

Oops, there is an O there, then that.1759

OK, now, let’s go ahead and draw in what it is that we have got.1763

We have OH, OH, OH, OH, CH2OH, lots of hydroxys.1767

Carbohydrates are just full of hydroxys.1780

OK, OH, OH, CH2OH, and the last one, OH, OH; and, of course, this goes on that way, and, of course, we have a CH2OH.1784

OK, now, this is what we started off with; this is the piece of our glycogen.1801

What we do to this is we methylate it, so every free hydroxy is going to be methylated.1805

Everywhere there is a free hydroxy, you are going to end up with OCH3 instead of OH.1810

Let’s go ahead and see where those are.1816

Those are going to be, well there, there, there, there, there, there, there, there, here, here and here, here, here and here.1820

Notice something here, on the free monomers, the ones that actually do not have a 1,6, that are not branched at the no. 6 carbon, those are going to end up once you actually methylate this and once you break all of these bonds, once you break them up into individual monomers, you are going to end up with something that is methylated at 3 points- 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3.1836

But, the free monomers that end up here, there is no hydroxy attached to this.1869

This no. 6 carbon and the oxygen attached to it is involved in a glycosidic bond.1877

So, when you break that bond, what you end up with is the (2,3)-Di-methyl-glucose, and what you end up with is also down up.1882

This is the (2,3)-Di-O-methyl-glucose.1908

Once you break that, these, the ones that have the branch points, this is not available for methylation.1917

Only 2 of them are available for methylation, so you get (2,3)-Di-O-methyl-glucose.1924

All of the others that are not involved in branching, that have no branching, those are going to end up having 3 methyl groups.1928

What you are going to end up with there is this.1937

You are going to end up with an OCH3 on the no. 2.1941

You are going to end up with an OCH3 on the no. 3.1945

There is an OH here because that is just a glycosidic bond.1948

The glycosidic bonds, they just end up back as hydroxys. but these OHs, you are going to end up CH2, OCH3.1953

You are going to have (2,3,6)-Tri-O-methyl-glucose.1960

That is what is going to happen when you hydrolyze it after you methylate it.1971

When you methylate it and then hydrolyze it, you are going to end up collecting 2 types of monomers: (2,3)-Di-O-methyl-glucose and (2,3,6)-Tri-O-methyl-glucose.1975

Well, if I can measure the amount of this, that will tell me how many of these are actually involved in branching.1985

Well, if I can take the total number of moles of monomers, or if I can take the number of these that are actually involved in branching by counting this derivative of it, divide it by the total number of monomers, I have my percentage of branching.1993

That is what I am doing here; I hope that made sense.2010

OK, now, let’s go ahead and actually run the calculations.2013

OK, let me see, comes from branching one of the hydroxys, yes, branching.2018

OK, 225mg of the glycogen is treated as above.2027

24.5mg of the (2,3)-Di-O-methyl-glucose is recovered.2032

What percentage of the glucose residues in glycogen are involved in branching?2036

Assume a glucose residue is a 162g/mol.2042

The hint here is recall what we mean when we use the word residue.2047

So, just as a recollection, when we talk about a residue, we are not just not talking about an amino acid residue.2053

We can talk about a glucose residue, an amino acid residue.2059

A residue is a general term for a molecule that has the elements of water removed from it, right?2062

Hydrolysis, you take off the OH, you take of the H, that is what you are doing; that is what a residue is.2070

When we talk about an amino acid residue, it means we have taken off an OH from the carboxyl end.2077

We have taken off an H from the amino end, and we have that residue.2083

So, we have actually lost 18g/mol for individual molecule.2086

When we talk about a residue of glucose, that means it is the glucose molecule that we know; but it is missing a hydroxy, and it is missing an H.2091

In other words 18g is missing, per mole.2100

That is what residue means, and that is going to be important in just a minute.2105

OK, what we want to do is the following.2107

The amount of the (2,3)-Di-O-methyl-glucose divided by the total amount of monomer of glucose times a hundred, that is going to give us our percentage.2113

And again, we did that by derivatizing it in such a way, so that when we finally hydrolyze it, you are going to end with 2 types of monomers.2139

The ones that have the branching points only have 2 methyls- the 2,3.2145

All of the other glucose monomers have the 2,3,6- those we do not care about.2150

We care about the 2,3, not the 2,3,6.2154

OK, let’s go ahead and do the math on this one.2157

Once again, we are not doing percent by mass, so we cannot just take the 24.5, and divide it by the - what is it - 225.2164

That is the whole idea; we have to be very, very careful.2179

It did not say percent by mass or percent by volume or something else; it actually said just what is the percentage, so we are talking about numbers.2182

We cannot use the masses directly; we have to go to moles because a mole is a measure of the amount in chemistry.2190

OK, let’s go ahead and calculate what it is that we have got.2197

We have, what did we say, 225?2202

OK, we have 225mg of glycogen, the total molecule; and we said that the average glucose residue, again, glucose is involved in this polymer.2205

That means that it has undergone a condensation reaction, so the elements of water have been removed from each glucose monomer in the actual molecule.2224

When I talk about 225mg of glucose, the 162g/mol, that is the weight of the residue.2233

Now, I am going to go ahead, since it was given to me in milligrams, I am just going to go ahead and write 1mmol is 162mg.2245

You can use these prefixes milli, centi, deci, kilo, as long as you change both of them, so millimole, milligram.2258

Do not change one of them, so 162g/mol is 162mg/mmol, 162kg/kmol.2265

As long as both, then you can just use the numbers as written.2277

You don’t have to write 225mg as 0.225g- that is it.2280

It is a personal thing; I just prefer to work like this by using the numbers that they gave me.2285

You could have written 0.225g x 1mol / 162g.2290

OK, now, I am not exactly sure, but I think my arithmetic was actually wrong on this.2295

So, I am just going to write down what it is that I have on a piece of paper, but I hope that you will verify this for me.2301

I think I used the wrong number here when I did this original division, but I ended up with 1.5mmol, which I’m sure is the wrong number; but again, the number is irrelevant.2306

It is the process that is important.2317

OK, now, let’s go ahead and do our number of moles of the (2,3)-Di-O-methyl-glucose.2320

We said that we recovered 24.5mg of the 2,3 derivative; I will just put 2,3 like that.2327

Now, 1mmol of that, when you calculate the molecular weight of that, it is going to end up being 208mg.2336

So, I end up with a total of 0.1178mmol of that.2347

OK, good.2356

Now, let’s go ahead, and we are done.2360

We have that; we have that.2365

We will take 0.1178mmol divided by 1.59mmol, which I think is not the right number.2368

225 divided by 162, I do not think it is 1.59, but I hope you will double check with me; and if it is not, just use a different number- it is not a problem.2378

Times a hundred, you end up with 7.5%.2387

7.5%, of all of the individual glucose monomers in this glycogen molecule, have a branching at the no. 6 carbon.2392

The amount of branching, the extent of branching in glycogen, this particular case based on this measurement is 7.5%, which makes sense.2401

It is going to be somewhere in the range of about 7-10% branching.2411

There you go; I hope that made sense.2415

Thank you for joining us here at Educator.com.2419

We will see you next time, bye-bye.2421

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