Home » Chemistry » Biochemistry » Polysaccharides, Part 2

Raffi Hovasapian

Raffi Hovasapian

Polysaccharides, Part 2

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Table of Contents

Section 1: Preliminaries on Aqueous Chemistry
Aqueous Solutions & Concentration

39m 57s

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

38m 53s

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

29m 1s

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

39m 11s

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

41m 33s

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

44m 19s

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

18m 45s

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

38m 19s

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

27m 14s

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

48m 28s

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

45m 18s

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

42m 47s

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

1h 2m 33s

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

49m 12s

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

54m 31s

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

50m 52s

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

51m 36s

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

1h 3m 36s

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

1h 7m 16s

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

41m 38s

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

44m 2s

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

56m 40s

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

20m 37s

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

51m 37s

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

51m 23s

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

54m 49s

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

1h 17m 46s

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

37m 6s

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

43m 32s

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

39m 25s

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

44m 15s

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

44m 23s

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

40m 22s

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

54m 55s

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

38m 51s

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

38m 20s

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

48m 36s

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

45m 51s

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

37m 6s

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

44m 32s

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

30m 8s

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

49m 46s

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

56m 34s

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

42m 12s

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

43m 32s

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

1h 1m 47s

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

59m 17s

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

39m 47s

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

41m 34s

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

34m 18s

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

42m 52s

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

36m 10s

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

49m 20s

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

44m 11s

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

48m 11s

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

45m 58s

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

33m 18s

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

40m 59s

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

39m 18s

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

36m 21s

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

47m 58s

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

41m 11s

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

36m 27s

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

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
  • Polysaccharides 0:17
    • Example: Cellulose
    • Glycoside Bond
    • Example Illustrations
    • Glycosaminoglycans Part 1
    • Glycosaminoglycans Part 2
    • Glycosaminoglycans & Sulfate Attachments
    • β-D-N-Acetylglucosamine
    • β-D-N-AcetylGalactosamine
    • β-D-Glucuronate
    • β-L-Iduronate
    • More on Sulfate Attachments
    • Hylarunic Acid
    • Hyaluronates
    • Other Glycosaminoglycans

Transcription: Polysaccharides, Part 2

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

Today, we are going to continue our discussion of polysaccharides, and talk a little bit about cellulose, another polysaccharide; and we are also going to introduce these things called the glycosaminoglycans.0003

Let's get started.0015

OK, as far as cellulose is concerned, I thought we would introduce that with an example, get a little practice, a little more practice with drawing structures.0018

I hope I am not making you crazy with drawing all these structures.0028

It is very, very important to be able to handle them without any problems.0031

OK, let's start with, cellulose is a structure - remember we said that polysaccharides have many different things that they do.0035

One of the things was fuel storage with starch and glycogen.0054

Well, structurally, some polysaccharides …cellulose is one of the structural polysaccharides, homo, and it is a homopolysacch consisting of glucose, and this time, we have a beta-(1,4)configuration, beta-(1,4) glycosidic bonds.0058

We had alpha-(1,4) for starch and glycogen; now, we have beta-(1,4).0100

Just by changing the configuration- totally different molecule, totally different chemistry.0105

OK, what we want you to do is to draw a trimer - 3 individual monomers - in a Haworth projection.0110

OK, let's go ahead and draw our monomers.0126

We know we are dealing with a homopolysaccharide.0130

Let's go ahead and do this in blue.0132

So, it is just glucose, so let's draw out 3 glucose monomers.0134

We should be all pros at this already.0140

Beta-configuration, beta means we have the hydroxy up here.0146

Let's go ahead and draw each glucose before we move on to the next glucose.0148

And then, we have another one.0155

That is there, and beta-configuration, and this.0159

Oops, let me work from right to left.0164

This is down; this is up.0168

This is down, and this is CH2OH; and, of course, we have one more.0169

Here we go, and this is beta.0176

This is down; this is up.0184

This is down, and we have CH2OH.0186

And again, I tend to not draw the thickened lines simply because that is just sort of a habit that I have gotten into, but if your teacher wants them, they are there, if not, that is fine.0191

Here is going to be the connections.0204

Beta-(1,4)...let me go ahead and do it in black.0208

I have got my 1 carbon, my 4 carbon, my 1 carbon, my 4 carbon.0212

What is happening is the elements of water - this is a condensation reaction - the elements of water are going away.0217

This oxygen is going to connect to that carbon.0230

This oxygen is going to connect to that carbon.0234

This is going to be our beta-(1,4) glycoside bond.0237

Now, let's go ahead and draw that; I am going to draw this one in black.0241

I will go boom, boom, boom.0248

I am going to go ahead and draw in the trimer, and then I will go back and put on the individual substituents.0251

This is O, like that.0258

I should probably draw it a little bit bigger than that; sorry about that.0267

And then, of course, we have this, and this is going to go on that way; and this is going to go on that way.0272

Now, we can go ahead and fill it in: OH, OH, CH2OH.0283

We have OH, OH, CH2OH.0292

Let's make this one a little bit better, and we have OH, OH, and CH2OH.0297

There we go; this is our basic trimer arrangement.0308

Notice they are all like this, and this is the glycosidic bond.0311

We have our beta-(1,4), beta-(1,4).0316

This is the beta right here, this and this.0321

We have drawn it, the bond this way, the bond this way, to show that this oxygen is actually up, beta; and this one is a down.0324

Now, I am going to go ahead and draw this not in another configuration, just a different representation of this actually showing the bonds a little bit more directly.0330

This is just another way of drawing it, and you are welcome to do it like this.0344

It is not a problem.0347

OK, so, we are going to have something like this.0349

I am going to start on this side, and let me do this in blue.0352

I have got, that is that; I have got O.0357

This is O; here, this is O.0370

This is there; this is there, something like that.0375

And, of course, it just sort of goes on like this.0380

That goes that way; that goes on that way.0384

And then, of course, we have our OH, OH, CH2OH, OH, OH, CH2OH.0389

All I have done is I have actually represented.0402

Instead of drawing them all straight like this, I have actually shown them in a sort of a stair step pattern just to show that more directly to the eye that this is below, this is above.0405

Let me go ahead and finish my substituents here, and I will go ahead and label some carbons.0418

Let's do that in black.0424

This is our alpha-1, no, not alpha-1; this is beta-1.0426

This is beta-(1,4); this is beta-(1,4).0432

The hydroxy is above the 4; the oxygen is below.0437

So, this is another way that you can draw it if you want to.0442

OK, now, I will do 1 final representation in order to show the geometry at the oxygen of the glycosidic bond, oxygen of the glycoside bond.0444

In other words, in order to show the geometry here, it is often drawn like this.0480

This is probably how you are going to see it in your book, at least one of the pictures...drawn like this as follows.0488

And again, you know oxygen, water, this is not a linear molecule; it is bent because we have these electrons here.0498

So, the geometry is a bent geometry; this is a linear geometry.0505

The picture before this, we had these curvy lines showing the arrangement, but now, in order to show the geometry, we are going to have to flip some of these monomers around.0509

Let's go ahead and draw what that looks like.0521

I am going to draw this one in black.0525

I am going to draw a central 1 first.0529

I have got that, that, that.0533

OK, I have got O, and I have got O.0537

Let me go ahead and draw my central 1 in here, CH2OH.0541

Now, a little bit different, this is going to be there.0548

This time, I have got my O here, and I have got CH2OH.0554

I have got OH; yes, that is correct, and of course, this one is going to be up.0566

And, of course, this one is going to be...let's just go ahead and put that there.0574

Let's put that there, and now, we will go ahead and put our O here, and we have our CH2OH.0579

We have OH, and we have this O there, and that goes on.0593

I am missing an OH; yes, that goes right there.0599

So, notice what I have done; I have taken this one.0602

I have left it the same; let me do this in red.0606

I have taken this thing, and I have left it the same.0610

I have flipped this one down, in order that this bond, now, shows the normal geometry of oxygen.0614

By flipping it down this way, what I have done is I have brought the oxygen which is in the back right; now, it is in the front right.0623

Same thing, this one, I have flipped up.0634

I have just flipped it in order to show the geometry at that oxygen and that oxygen.0637

And again, same thing, what used to be an oxygen on the back right, is now, an oxygen on the front right.0643

In order that we can show the geometry, this is probably how you will see it.0649

And again, when you look at these things in your book, when you are looking through multiple structures, you want to make sure...a polymer of glucose can be any different kind of molecule, what is important is the nature of the glycosidic bond, alpha or beta, what carbon it is attached to.0656

And, what you are looking for in these structures if you are just looking at it as opposed to drawing it with your hand, you are looking for where this oxygen is in the ring.0675

That is what is going to tell you what molecule you are dealing with.0683

So, this one might happen to look like some other polysaccharide, a glucose, but you need to be very, very careful, and identify where the oxygen is and what the glycosidic bond is.0687

Here, you have your beta-1, and this is 4; and this is 4, and this is beta-1.0703

This is beta-1, and the reason it is beta-1 is, under normal circumstances where the oxygen is in the back right, the standard way we actually arrange things, the oxygen is up.0715

That is the beta-configuration, but by flipping it, now, the oxygen is below the ring; but the oxygen here is in the front right.0727

So, that confirms the fact that this is a beta-1 configuration.0734

Just by looking at the hexose, it looks like it is an alpha because the oxygen is below; but the oxygen is here.0737

The oxygen in the ring is down here, not back there, so this is a beta-configuration- very, very important.0743

OK, let's see what we have got.0751

Let's take a look here at some actual illustrations.0755

We have our standard here, beta right?0760

This is the beta-carbon; this is the beta-1, and over here, this is our no. 4 carbon.0767

But notice, this time, we have left this particular one on the left in the beta-configuration under normal circumstances, the standard Haworth projection with the oxygen on the back right.0775

This time what we have done is we have taken the other one, and we have flipped that.0789

Notice where the oxygen is; the oxygen is in the front right.0793

These are the things that we have to recognize.0796

We know that glucose 1, 2, normally 1, 2, 3, 4, the oxygen is below the ring.0799

Here, the oxygen is above the ring.0806

Well, it is above the ring because I flipped the molecule, flipped it like this.0808

Now, this no. 4 carbon, the oxygen goes up.0812

Again, this shows the geometry at this particular oxygen.0816

These are the things that we have to watch out for.0820

They are going to be drawn in any number of ways.0824

What we want to do is look and see what is where, and that will tell us what is happening.0827

OK, this particular vision right there, this is the same thing, except now, it is going to show some of the hydrogen bonding that takes place among the different monomers in a polysaccharide or an oligosaccharide.0832

So, in this particular case, we have some hydrogen bonding taking place here.0847

We have some hydrogen bonding taking place here.0851

This is hydrogen bonding within the chain itself, and the hydrogen bonding, in addition to the geometry in the oxygen, is going to dictate how this molecule looks in 3 dimensions, how it folds, how it spins this way, how it turns this way, how it bends this way; and that is going to have an effect on the chemistry.0855

That is the whole idea behind the organic chemistry.0878

Structure is function- that is the whole idea.0882

What this thing looks like in 3-dimensional space - the final shape that it takes - is going to dictate what function it serves.0885

Now, this is an extended network of hydrogen bonding.0893

So, we have hydrogen bonding within an actual chain, but in another chain, there is also some hydrogen bonding going on here and here and here and here.0897

Again, all of this, the net effect is that all of this has an effect on the final structure of a cellulose molecule, if you want.0908

I mean it is just an extended polymer- it is what it is.0922

It is not an actual molecule, but there you go.0925

You have the glycosidic bonds; you have the particular arrangements.0928

You have the hydrogen bonds within, among the individual monomers in a chain; and you also have a hydrogen bonding between the chains, and that is the whole idea.0933

Again, you have got hydroxys all over these carbohydrates, so clearly, there is going to be a lot of hydrogen bonding.0942

It plays very, very important role in the structure of carbohydrates.0948

OK, let's talk about a different family of polysaccharides.0953

These are called the glycosaminoglycans- very, very important.0960

OK, now, let's go ahead and this is going to be a bit long, but it should not be too bad.0977

Now, these are heteropolysacchs; up until now, we have been talking about homopolysaccharides.0984

We have been using just glucose.0989

These are heteropolysaccharides of the extracellular matrix.0996

Now, the extracellular matrix is just a fancy word for that jelly-like substance that is outside of the cells, that tends to hold cells in place.1006

You cannot just have cells wandering around everywhere.1015

Certain tissues are cells that are there; they are held in place.1019

They don't move around; they are held together by this thing called the extracellular matrix.1025

It is basically just a scaffold for these cells to be; it keeps them in place.1029

That is all it is; that is all you want to think about it as.1034

They are heteropolysaccharides of the extracellular matrix, which is a gel-like substance - probably the best way to think about it, just a gel-like substance - that provides support for cells - in animal tissues, anyway - in animal tissue, as well as, provides a porous network for the movement of oxygen and nutrients, OK, oxygen and nutrients to individual cells.1038

That is it.1110

OK, now, the glycosaminoglycans, I am going to actually abbreviate this as Gag.1113

You will also see this in your book.1127

The glycosaminoglycans, they form a family - linear heteropolysaccharides, heteropolysacchs - composed of repeating disaccharide units.1129

So, what you have is, it is a heteropolysaccharide, and that is has, in this particular case, it is made up of 2 monomers.1166

Those 2 monomers are going to alternate, so A, B, A, B, A, B, A, B.1173

You can think of a disaccharide, that A-B, as one unit.1176

You have A-B, A-B, A-B, A-B; that is what we mean by a heteropolysaccharide composed of repeating disaccharide units.1180

That is all it means.1189

OK, now, one of the disaccharide units, one of the disacchs, one of the monomers of the disacch, is either N-acetylglucosamine or N-acetylgalactosamine.1191

I am having a hard time writing today; sorry about that.1241

And, in a minute, we are going to start to use the abbreviations.1250

OK, the other monomer of this disaccharide unit, the other monomer, is most often a uronic acid; and uronic acid, for your quick recollection, if you go back a lesson or two, it is where the no. 6 carbon has been oxidized to a carboxyl group, COO-.1254

And, the two that you will probably see are D-glucuronic acid - and don't worry, we are going to be going over the structures in just a minute, D-glucuronic acid or D-glucuronate for the one that has been deprotonated, which under physiological conditions, it actually shows up as COO-, not COOH, so D-glucuronic acid and interestingly enough, the L-isomer of iduronic acid.1299

More often than not, these glycosaminoglycans, they consist of N-acetylglucosamine as one of the monomers, and some uronic acid as the other monomer; and those 2 units will alternate, and they will keep repeating.1332

Instead of the N-acetylglucosamine, you might have N-acetylgalactosamine.1350

Again, just another hexose, the hydroxy has just changed.1357

OK, one last thing before we start looking at some structures.1360

OK, in some of these Gags, in some of these glycosaminoglycans, one or more of the hydroxys have sulfates attached.1369

In other words, let's say you just have something like, let's say this one, CH2, instead of the OH that has a sulfate attached- that is all.1403

It could be at this one; it could be at this one, this down, up, down.1423

It can be on this one; it can be this one.1431

It can be this one; it could be any two.1432

It could be any three; the different arrangement of the sulfates along this linear polymer actually becomes a site of recognition for different proteins.1434

So, the arrangement of sulfates, the number of sulfates, the density of them has different recognition, it serves recognition, function for proteins that need to bind to them electrostatically.1444

Obviously, if you have a bunch of sulfates, you have a high degree of negative charge, so there is going to be a lot of electrostatic interaction.1455

I just wanted you to know that in some of these, one of more of the hydroxys has a sulfate attached to it- that's it.1460

OK, let's take a look at some of these structures first.1468

Let's do this in black; let's look at the monomers.1473

Let's look at the monomers.1479

Now, we said N-acetylglucosamine, so that is going to look like this, this, that, that, boom.1490

Let's go ahead and do the beta version.1500

We have N; we have C.1503

We have CH3; we have OH, OH, and we have CH2OH.1506

This is N-acetylglucosamine.1513

This is the beta-D-N-acetylglucosamine.1518

Its shorthand is Glc - no, I need my N-GlcNAc.1529

That is N-acetylglucosamine.1539

OK, now, let's do the N-acetylgalactosamine.1541

We have got this, make it a little bit broader here.1546

Let's do the beta form, and again, we have an N.1551

We have a C, and a CH3.1556

This is our N; this is our acetyl group.1560

This one is up, and galactose is a 1, 2, 3, c-4 epimer, so CH2OH.1563

So, here, we have beta-D-N-acetyl…wooh, this is tiring, makes me crazy having to write all these stuff out.1573

This one is GalNAc.1586

That is the shorthand for that one.1590

OK, now, let's do our glucuronic acid and our iduronic acid.1592

Do I want to do them on this page or the next page?1598

You know what, I think I will go ahead and stay on this page.1600

Hopefully, there is enough room here.1604

I have got this; I have got that.1605

Alright, there is that; I will go ahead and do the beta, and this is there.1610

This is there, and this is there; and we said that the no. 6 carbon has been oxidized.1618

So, this one is our - that is what makes it - so, this is beta-configuration D.1625

D- hat is the configuration here and glucuronate.1640

Now, I did the glucuronate instead of the glucuronic acid.1645

The glucuronic acid would just be this protonated- that's it.1649

That is the only difference, so glucuronate.1651

OK, acetic acid, acetate, propanoic acid, propanoate, the A-T-E just tells me that I am deprotonated; and at physiological pH, I am going to be deprotonated.1654

This is beta-D-glucuronate glucuronic acid.1666

Now, let's do the beta-D-iduronic acid, the other particular monomer.1670

Let's see; let's go ahead and go here.1675

Let's see if I can do this one.1679

Alright, let's do this as a beta-configuration.1682

Now, this one is going to be OH.1686

This is a little different, and this is going to be OH; and here, we are going to have the COO-.1690

Here, this is the L; remember, we said it is L.1700

This is beta-L-iduronic, iduronate or iduronic acid.1704

The L-configuration, remember, if we said any 2 substituents, we change configurations.1714

The D in the L is based on the chiral carbon that is farthest from the carbonyl.1723

The carbonyl carbon is this one; that is the anomeric carbon.1732

It is the no. 5 carbon - 1, 2, 3, 4, - that decides D or L.1735

D the CH2OH, which is now carboxyl, is above the ring.1740

The L-configuration just switched the H and the CH2OH.1745

Now, the CH2OH, or which is now the COO-, that is below the ring.1749

OK, this is L; this is D.1754

A galactosamine, in general, has one of these and one of these alternating.1757

Let's say we have N-acetylglucosamine and we have beta-D-glucuronic acid, A, B, A, B, A, B, that is going to be a particular glycosaminoglycan.1763

OK, let's see what we have got.1777

Now, and let me just write down one thing regarding the sulfate attachments.1783

Yes, that is fine; I will go ahead and write it down.1790

OK, regarding the sulfate attachments, I am just going to reiterate what it is that I said before.1793

The pattern of attachment provides for recognition by protein molecules which can bind electrostatically.1807

Now, protein molecules can also bind covalently, but in this particular case, it tend to bind electrostatically.1849

Oligosaccharides, polysaccharides, sugars, carbohydrates, on the cell surface, are how cells recognize each other.1858

The whole idea of recognition is all based on the arrangement of sugars on the cell surface- a particular configuration, a particular arrangement, 15 monomers, 27 monomers.1866

That is how individual body, individual cells recognize each other and communicate with what is happening inside the cell.1877

Glycobiology- profoundly important, and it is a fantastic, fantastic area of research that is only just beginning.1885

It is really only just beginning.1892

There is so much work to be done and so many wonderful new things to be discovered in this absolutely amazing, amazing field of biochemistry.1894

OK, let's take a look at some of these glycosaminoglycans.1903

Let's go ahead and go to blue; there we go.1907

Let's take a look at some glycosaminoglycans, some Gags.1913

OK, the first one we are going to look at is hyaluronic acid.1920

This is hyaluronic acid or hyaluronate, and this particular Gag is made up alternating monomers of GlcA and GlcNAc.1925

Oh, you know what, I think in the last page, when I did the glucuronic acid and the L-iduronic acid, I forgot to put the symbols.1957

So, this GlcA, that stands for the glucuronic acid.1969

That is the shorthand for glucuronic, and then, of course, we have the IdoA.1977

That is the iduronic acid; sorry about that.1985

OK, in this particular case, this particular glycosaminoglycan called hyaluronic acid, it has alternating monomers of glucuronic acid and N-acetylglucosamine- A, B, A, B, A, B.1992

OK, and here is the pattern of the binding for the glycosidic bond.2005

I am going to do this with 3 monomers.2010

Let me go ahead and do this in black.2015

This is going to be GlcA.2020

It is going to be beta-(1,3) - very unusual, very unusual - beta-(1,3) GlcNAc.2025

This one is going to be beta-(1,4); this is a little bit more normal.2033

And then, we have GlcA again, and then it goes on like that; and, it is going to be somewhere in the neighborhood of about 50,000 monomers.2037

It is a pretty long molecule.2049

Left to right, the glucuronic acid connected to the N-acetylglucosamine is connected by a beta-(1,3) glycosidic bond; and the N-acetylglucosamine connected to the next glucuronic acid is connected by a beta-(1,4) bond.2053

So, we have everything that we need right here in order to draw out the structure.2070

Now, let's go ahead and draw out the structure.2074

OK, let me start with a GlcA on this side.2076

Again, glucuronic acid, let me do this in black.2082

I have got this, that, that.2087

Now, let me go ahead and draw those two.2093

This is going to be the glucuronic acid.2102

This is going to be OH; this is going to be OH.2106

This is going to be OH, and this is going to be the COO-.2110

That is the carboxylate.2114

Now, we said that it is connected in a beta-(1,3).2116

Well, this is the anomeric carbon.2119

Let me number these; this is the no. 1 carbon.2124

This is no. 2; this is no. 3.2126

Over here, what we have is...let me go back to black.2133

This is going to be the N-acetylglucosamine, so this is NH.2137

I am thinking in the last structure, I think I forgot the H on the nitrogen; sorry about that.2141

OK, this is going to be C.2145

This is going to be CH3; this is down.2149

Now, here, on the no. 3 carbon, let me actually say the numbers until afterward; I think it is a little bit better.2153

So, here, this is going to be O, like that; and, of course, here, we have the OH, and we have CH2OH.2160

Let me draw a couple of more of these, and then I will go ahead and discuss these particular glycosidic bonds on this molecule.2179

Let me see; let me go ahead and do this.2189

Let me go ahead and do that.2191

I will just make it a little bit quicker here.2194

COO- and I’ve got an OH on top; I’ve got OH on the bottom.2197

This is glucuronic acid, OK.2203

I have got this one here, and I’ve got this.2205

It is going to be O there; this is going to be a CH2OH.2214

This is going to be glucose, and this is going to be, this one is up, and this one is down; and let’s go ahead and leave it as beta.2226

Let’s just write 4 of those units right there.2237

OK, let’s take a look at what we have got here.2239

This is our GlcA, and this is our GlcNAc.2243

This is our GlcA, and this is our GlcNAc- glucuronic acid, N-acetylglucosamine, glucuronic acid, N-acetylglucosamine.2252

A-B, A-B- just keeps going in this direction and this direction; and the GlcA to the N-acetylglucosamine is beta-(1,3).2263

Well, here is our beta-1, and here is our no. 3.2271

Notice, beta-oxygen above 3 glucose, the no. 3 carbon, the oxygen is above the ring.2275

The hydroxy is above the ring, that is why we drew it this way; it is very, very unusual.2283

Now, N-acetylglucosamine connected to GlcA, with N-acetylglucosamine on the left, GlcA on the right, is connected with a beta-(1,4).2288

Well, here is our beta-1; this is our beta-1 carbon, and here is our no. 4 carbon.2299

And then again, GlcA to N-acetylglucosamine, it is going to be beta-(1,3).2304

This is our beta-1; this is our no. 3 carbon- that is it.2312

If you have this and if you know what the individual monomers look like, that is there, this is there, and that is there, and this is...oops N-acetylglucosamine, that is not right.2319

This is NH; sorry about that, COOCH3.2334

Yes, I know; a whole bunch of carbons, oxygens, and things floating around.2341

It is very easy to lose your way as you can see.2346

OK, that is it.2348

Once we have this arrangement, once we know what is connected to what, we can draw up out structure.2350

If we are given the structure, we should be able to go backward; we should be able to recognize this is a uronic acid.2356

This is N-acetylglucosamine; this is a beta-1 configuration no. 3.2362

We should be able to write this out, you have to be able to go both ways.2366

OK, now, let’s talk about these hyaluronates or these hyaluronic acids.2370

Not only do they form part of the extracellular matrix, they actually form the lubricants for your joints, lubricants in your joints, and they also happen to give your eye that jelly-like consistency.2386

So, I can do that because of these hyaluronic acids.2407

Now, I am just going to go ahead and list some other glycosaminoglycans, and I am going to list them; and again, I am going to encourage you to use your book because it is your primary resource.2410

It is a fantastic resource with wonderful pictures and further discussion of what these individual glycosaminoglycans happen to do.2421

And again, we are just learning what these things do very, very recently.2431

Glycobiology, it is a brand; it is your definitely ground level if you want to get into glycobiological research- fantastic area.2438

Let me do this in blue here.2445

Other glycosaminoglycans, and I encourage you to take a look, maybe do a little bit of look on the web, look on your book- whatever it is that you need to do.2449

I am not going to talk about them again.2461

The only difference is you have different monomers, but it is always going to be a disaccharide unit.2463

It is always going to be an alternating A-B, A-B, A-B.2468

You are not going to have a C, a D, an F.2471

It is going to be, it is hetero, but there is only 2 monomers that make up this linear chain; and there is not going to be any branching.2473

Glycosaminoglycans, at least, not that we have discovered yet; I could be wrong.2482

That is the wonderful thing about biochemistry- you will never know what is going to happen tomorrow.2488

OK, some important ones, some of these you have actually heard off.2493

Chondroitin-4-sulfate, this chondroitin-4-sulfate, this just means that the hydroxy on the no. 4 carbon...so, if I just take some random 1, 2, 3, 4, either there or there.2498

I will not specify the stereochemistry.2516

OK, this could be glucose; it could be galactose, so I will just put OH here.2518

OK, it could be any stereochemistry, above or below.2521

This has been sulfated; that is all this means- 4-sulfate, chondroitin-4-sulfate.2525

Maybe it is 3 sulfate; maybe it is 6 sulfate that tells me the carbon that has been sulfated, the carbon that has the oxygen attached, that has the sulfate attached to it.2536

OK, chondroitin-4-sulfate generally tends to be in the range of about 20 to 60 monomers- very, very short.2548

These are a lot shorter than the hyaluronic acid; hyaluronic- they are huge.2555

These tend to be very, very short.2560

Keratin sulfate, somewhere in the range of maybe 25 monomers.2564

Heparin- definitely a molecule that you want to get to know well.2574

And, those of you that are going to be going on into medicine, you will get to know it very, very well.2577

Heparin, somewhere in the range of 20 to 90- a lot of variation.2581

OK, clearly these are much shorter.2588

You know what, I don’t need to write that; I mean, clearly, you know that these are much shorter, obviously.2600

We said that 50,000 versus let’s say 20 unit; yes, it is a lot shorter.2604

OK, these tend to be covalently linked to proteins.2610

So, if you run across a keratin sulfate, heparin, chondroitin-4-sulfate, any number of things, these will tend to be covalently linked to some type of a protein.2631

OK, that finishes our discussion of polysaccharides- almost, actually.2644

We have a little bit more to discuss, but that certainly finishes today’s lesson.2648

Thank you for joining us here at Educator.com.2652

We will see you next time, bye-bye.2653

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