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Raffi Hovasapian

Raffi Hovasapian

Polysaccharides

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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Last reply by: Professor Hovasapian
Fri Jul 6, 2018 5:22 AM

Post by Swati Sharma on July 4 at 01:56:32 PM

I secured 95% in my Biochemistry class last semester and it was all due to your lectures. Now I am using the same lectures to prepare myself for MCAT Biochemistry. I am using only Educator.com for MCAT prep since it has helped me preventing to spend 5000 dollars on MCAT prep classes(Kaplan, Princeton etc.)  which mainly does content reviews  which I can do it myself via educator.com.

Can I use your AP chemistry videos for MCAT prep? I am not sure what AP means but I am assuming its university level course. Please let me know and thanks for great lectures.

Polysaccharides

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
  • Recap Example: Draw the Structure of Gal(α1↔β1)Man 0:38
  • Polysaccharides 9:46
    • Polysaccharides Overview
    • Homopolysaccharide
    • Heteropolysaccharide
    • Homopolysaccharide as Fuel Storage
    • Starch Has Two Types of Glucose Polymer: Amylose
    • Starch Has Two Types of Glucose Polymer: Amylopectin
    • Polysaccharides: Reducing End & Non-Reducing End
    • Glycogen
    • Examples: Structures of Polysaccharides
    • Let's Draw an (α1→4) & (α1→6) of Amylopectin by Hand.
    • More on Glycogen
    • Glycogen, Concentration, & The Concept of Osmolarity

Transcription: Polysaccharides

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

Today's lesson, we're going to start talking about polysaccharides.0004

These are just long chains of individual sugar units, glucose, galactose, mannose any number of possible, so, it is just long chains of them- that is all.0008

Instead of a disaccharide, so now we have multiple monomers.0019

Let’s go ahead and get started.0023

Before we do though, I just want to do a quick recap, one more example for disaccharides just so we can get a little bit more practice with actually drawing the structures out by hand.0025

We need to be able to draw them out by hand, not just by recognize them passively.0033

Let's do a recap example here before we get started.0039

OK, so, a recap example.0047

We would like you to draw the structure of galactose - oops let me make this L a little bit better here - of Gal(alpha1)(beta1)Man.0051

Galactose, alpha-1, beta-1, so the glycosidic bond between the galactose and the mannose is going to be the alpha-1 carbon of the galactose, the beta-1 of configuration of mannose.0074

Let's go ahead and draw this out.0085

Let's see; the first thing we are going to do, I’m going to start off by drawing the linear structures and then the rings, and then I'll put the rings together.0090

It is always a great way to do it like this; this way, you are always nice and systematic.0097

Galactose and mannose are both hexoses, so we have 1, 2, 3, 4, 5 and 6.0102

Let's make them a little big here.0110

OK, we have got OH, OH, OH, OH and CH2OH0114

This is going to be our alpha-galactose.0123

Actually, not alpha yet, it is just galactose because the alpha and the beta configurations are when they are actually in a ring.0127

So, you notice we have right, left, left, right, 1, 2, 3, 4; galactose is the c-4 epimer of glucose.0134

OK, this is our galactose.0143

Now, we are going to put it together with our mannose.0146

Again, we have a 6-carbon sugar, 1, 2, 3, 4, 5, 6; there we go.0149

We start with our aldehyde; let’s go ahead and put our CH2OH of the other end, and now, we can build what's in between.0156

This is going to be...no, this is mannose, right?0162

OK, mannose is a c-2 epimer, so this is going to be OH, OH, OH, OH.0167

You notice the 2 on the left, 2 on there right; this is our mannose.0175

OK, now, let’s go ahead and draw the ring structure for them0181

And again, what you do is you take this linear structure which is vertical; you rotate it to the right, and then you bring this side around the back, and then you make a little bit of a rotation, so that the OH is actually pointing to the right and the CH2OH is pointing up, and you'll see what it looks like in just a minute, and when you put it together, you get the following.0183

Yes, so we have - let me, yes, that's fine - so this, this, this, like that, and we have the alpha-configuration, so this hydroxy is down.0209

This hydroxy is down; this hydroxy is up, and this hydroxy is up, and, of course, we have our CH2OH.0223

That is what we did; now, we have our alpha-galactose aGal.0231

And now, let's go ahead and do our mannose.0237

Again, rotate it to the right; bring this aldehyde down to the right.0240

Now, this CH2OH, bring it around back, and then rotate this carbon right here, the no. 5 carbon, rotate this one.0245

So, the hydroxy is pointing to the right, and the CH2 is pointing up.0254

That is the deconfiguration, and when you do that, what you get is the following.0258

I'll go ahead and do this one in red.0263

We will draw the general 6 carbons, and we said this is the beta-mannose, correct, beta-1.0266

Beta, this is going to point up, right?0273

And then, looks like this one is also going to point up.0278

That is this carbon, and then on this one is going to go - let me see, wait, now, I'm lost - this is going to be up; this is going to be up.0281

This is going to be up; OK, sorry about that.0293

This is no. 1 carbon, no. 2 carbon, no. 3 carbon, 1, 2, 3.0295

So, we have taken care of those, and now, we have this one; this hydroxy is going to be down, and this is CH2OH.0299

As you can see, it is very, very important to keep track of which carbon we are looking at; this thing can be very, very confusing, so all the more reason to do it nice and systematically0307

OK, this is going to be alpha-1, beta-1.0315

In blue, we are going to be connecting this carbon with this carbon.0320

What I'm going to do is, this mannose, in order to draw it out and bring this carbon in close proximity with this one, I'm going to have to flip this.0323

Now, there are 2 ways that I can flip this molecule; remember we talked about spin and flip?0330

I think flip is probably the best way to go.0336

It seems to be the one that you see more often in biochemistry text books as opposed to spin, but you realize, this is a flat molecule, right?0338

So, we have this right here; let me go ahead and draw, so you can see.0348

This is Haworth projection; this is a flat molecule.0352

You are looking at it like that; you can flip it two ways.0355

You can flip it that way, or you can flip it that way, right?0358

There are two ways you can flip something, either side to side or forward and back.0364

In this particular case, let me go ahead and do this in blue.0368

I'm going to go ahead and flip it, and what I'm going to do is, I'm going to flip it sideways.0373

In other words, I'm going to bring this carbon here, and I’m going to bring this carbon over there.0377

OK, so I'm going to flip it sideways, that way, not this way, forward back.0384

When I do that, it is the oxygen that tells me how the flip has happened.0390

This is the thing, wherever the oxygen is, that is what tells me where to put the other substituents- the hydroxys and the CH2OH.0394

So, when I do the flip, I end up with this ring structure.0402

Now, the oxygen is on the back left.0407

OK, and now, let’s see what it is that I've done.0411

This OH, now, this is the no. 1 carbon over here, 1, 2, 3, 4.0414

Now, the no. 1 carbon is over here, and this is the no. 4 carbon.0419

OK, let me go back to blue.0425

OH is down here; this OH is going to be up there.0429

These have been flipped, so now, these are both down- that hydroxide and that hydroxide.0433

This one has been flipped over to the other side, and it is also down, so this is going to be over here, CH2OH.0438

Now, that is the arrangement.0447

Now, we are going to put this thing and this thing, so this is beta mannose that has been flipped.0450

Now, we are going to put this together with this; we are going to connect this carbon with this carbon, and when we do that - let’s go ahead and just draw our little equilibrium arrows - our final product is going to look like this.0459

I am going to do this in black, actually.0478

We have that, and remember, we do our little arrangement like this except this time, the O is over here, like that.0481

We have this OH; we have this OH.0498

We have this OH; this is in standard configuration.0501

The oxygen is on the back right, and over here we have flipped it, so now, the oxygen is on the left.0504

That means this hydroxide is here; this hydroxide is here.0510

This hydroxide is here, and this CH2OH group.0514

It is always interesting to try to draw it; I will go ahead and put the H2 there and the OH, and there we go.0520

This is our Gal(alpha1)(beta1)Man.0526

There you go, nice and systematic.0534

Draw out the linear structure; rotate them.0535

Create the ring structures in standard configuration with the oxygen on the back right, and then decide which carbons you are going to have to connect, and then decide which one of those monomers you are going to have to flip.0538

OK, flip, it is up to you.0548

You can do a flip or spin, as long as the arrangement of the substituents is such that it is very, very clear what is where.0550

If you want, you can go ahead and add a little stereochemistry by doing that, darkening up some lines.0557

Let me do that; I personally do not.0564

I just sort of leave it like that, but, of course, your teacher might want you to actually demonstrate the projection by showing the darker lines.0568

So, there you go; that is it- nice, basic disaccharide0574

As long as you know the structures of the monomers, which I imagine your teacher is probably going to have you memorize, everything should be nice and straight forward.0578

OK, let’s start our discussion of polysaccharides.0586

I will go ahead and I am going to do this in blue.0591

Polysaccharides, now, we are just going to be adding a whole bunch of monomers, one after the other on a chain, just like we did with proteins, except those were amino acids instead of sugar units.0595

Polysacchs- they are also called glycans, and this glycan name will come up.0608

In case it does, it is not a different type of molecule; it is just another name for a polysaccharide.0623

Now, polysacchs, they differ from each other - there is a whole, whole, whole bunch of polysaccharides - with respect to 4 things.0628

The monosacch units that actually make up the polymer.0654

Which monosaccharide units are we using?0658

Are we using only glucose or are we using glucose and galactose and mannose and n-acetylgalactosamine?0659

Which monomers are we using?0668

Chain length, you might have a polysaccharide that is only 15 monomers long.0671

You might have one that is 150 thousand polymers long, so chain length.0675

And, if you have, let's say, a bunch of glucose that is 15 long and a bunch of glucose that is 1500 long, those molecules are going to behave differently, just because they are made of the same monomer, glucose, the length will actually change the chemistry.0682

Branching along the chain - I'm sorry, branching along the, well, yes, branching along the chain.0700

What you are going to have is something like this.0716

You are going to have some monomer going on, going on, and all of a sudden it is going to branch off like this, and maybe branch off again, and then maybe branch off again.0717

Polysaccharides will do that, and we will see some examples in just a minute.0725

And, of course, the last thing that they differ with respect to is the nature of the glycosidic bond connecting the monosaccharides.0729

In the example that we just did - monosaccharides, just let me go ahead and write this out - our connection here was alpha-1, beta-1.0751

This is the no. 1 carbon; this is the no. 1 carbon on the mannose.0762

So, and alpha-1, beta-1, well, maybe if I had an alpha-1, alpha-1 mannose, that is going to be an entirely different polysaccharide simply by virtue of the nature of the glycosidic bond.0765

Totally different, totally different chemistry, totally different folding- that is the whole idea.0775

Small subtle changes make huge differences because you are talking about big molecules, and when all of these things sort of add up, you get entirely different chemistry.0779

OK, define a couple of more terms.0780

A homopolysaccharide is exactly what you think it is.0798

It is a polysaccharide made of 1 type of monomer.0805

I'll just write "1 type of monomer makes up the chain".0810

In other words, it is just the same monomer one after the other, glucose, glucose, glucose, glucose, glucose makes up the chain.0819

That is a homopolysaccharide, and, of course, heteropolysaccharide, you have 2 or more; but for formality's sake, let's go ahead and write it down.0826

A heteropolysaccharide- 2 or more monomers make up the chain.0835

Maybe you have an alternating glucose, mannose, glucose, mannose, glucose, mannose.0854

That is a heteropolysaccharide; there happen to be 2 of them.0858

There can be more.0861

OK, now, polysaccharides serve lots of purposes.0863

What is really, really exciting is glycobiology, the study of carbohydrates, it is a fantastic, fantastic area of research right now because every single day, literally, every single day, some new polysaccharide, some new protein attached to a carbohydrate, is being discovered that serves a whole different purpose; and that is what's amazing about this.0869

Polysaccharides, they serve many purposes; and certainly, many of the purposes we haven't even discovered yet.0894

There is plenty of room for growth in this particular field, and polysacchs, interestingly enough, they have no specific molecular weight.0900

They have no specific molar mass.0919

In other words, we don't talk about a polysaccharide that has a molar mass of 50,346g/mol.0924

It is not that precise; it is not like proteins where you have a specific number of amino acids if you have 1 more or 1 less.0933

It is an entirely different protein for the most part.0940

Polysacchs, when they are synthesized, we talk about a polysaccharide that is roughly 25,000 monomers long, 300 monomers long, more or less.0943

There is no specific molecular weight.0954

OK, now, let's talk about some homopolysaccharides that serve as a fuel storage.0958

One of the purposes of polysaccharides is as a reserve fuel source if the organism is not actually taking fuel in.0965

In our case, we tend to store fuel as glycogen; that is our primary polysaccharide for animals.0974

For plants, it is starch, so homopolysacchs serving as fuel storage.0981

And, we are going to talk about starch, and we are going to talk about glycogen; and both occur inside the cell.0999

Now, starch and glycogen are actually the same thing; they are made of the same thing- glucose.1017

It is just the degree of branching, as you will see in a minute, that is going to differentiate the glycogen from the starch- an entirely different chemistry.1022

It is actually amazing.1028

Let's talk about starch first.1030

Starch has 2 types of glucose polymers.1035

Starch is made of 2 types of polysaccharide chain.1048

One of those is called amylose or amylose; however you want to pronounce it.1053

It is glucose monomers connected by alpha-(1,4) glycosidic bonds, just one glucose after the other with the connection as alpha-(1,4), alpha-(1,4), alpha-(1,4) all the way down the line in just a straight, single chain.1060

Now, the other particular polymer for starch is amylopectin, and it is also glucose connected by the alpha-(1,4).1085

It has that chain, but along that chain, there are branch points; and those branch points - and, alright - and branching by alpha-(1,6).1100

So, at the no. 6 carbon, that CH2OH sticking up, it actually branches off at that point, and it starts a whole new chain.1121

And then maybe along that chain, it branches again; and it starts a whole new chain, so that is the difference.1131

Amylose and amylopectin, and they are sort of intertwined; and again, you will see it in a minute.1136

We are going to do a detailed structure, and then, sort of a broader structure.1141

OK, now, let's see what else do we want to talk about before we actually start looking at some structure.1146

Ah, yes, so, we talked about reducing sugars, non-reducing sugars, there is a reducing end, in other words, a free anomeric carbon that can react, that can be oxidized by iron ion or copper ion.1154

There is a reducing end, so polysaccharides, polysacchs, have a reducing end and many non-reducing ends because of the branching.1172

And this idea of the non-reducing end, having many of them, is going to play a very, very important role in physiology as we will talk about at the end of this lesson.1198

OK, glycogen, just one quick word about glycogen, it is the same as starch.1208

OK, in other words, it has the amylose; it has the amylopectin, but it is more highly-branched, and more compact.1220

Again, totally different chemistry simply by virtue of the branching.1240

Amylopectin, it might branch off maybe every 30 to 35 glucose units, 30 units and then it will branch off, 30 units and it will branch off.1244

Glycogen might do 10 units branch, 10 units branch, 5 units branch, 7 units branch.1256

It branches more often, and it tends to be more compact, more dense.1262

That is it; that is the only difference between the 2, but the fundamental structure is the same.1267

Alpha-(1,4) glucose units and alpha-(1,6) glucose, glycosidic bond at the branch point.1271

OK, let's go ahead and take a look at some structures here.1281

In this particular case, I am going to be presenting them as illustrations instead of drawing them out by hand simply because we want to save a little bit of time, but now, I think we have a little bit of a sense of what the glucose looks like, what the monomers look like, alpha-1.1285

We just want to be able to identify what is what, what is connected to what.1297

Let's take a look at some pictures, and the first one we are going to look at is amylose.1302

OK, we have our amylose, and we said that we have alpha-(1,4) and its glucose.1310

So, we have 3 monomers of glucose, so it goes off in this direction.1319

It goes off in this direction.1321

Let me go ahead and use, yes, let me go ahead and stay with red here.1323

Here is our 1,4; this is our no. 1 carbon, alpha-configuration.1328

This is our no. 4 carbon on the other.1333

This is our no. 1 carbon, alpha-configuration, the hydroxy is down; and this is our 4 carbon from the other side.1336

This is it; this is amylose.1344

I don't think I'm going to have to...that is fine, I'll just go ahead and...not a problem.1348

This is our amylose chain, and it goes off this way, and it goes off this way.1351

Now, at the end, of course, this is your reducing end.1355

The polymer will usually go on in that direction connected to this hydroxy.1361

Let me go ahead and actually do that.1366

It will end up being connected to this hydroxy.1369

Here is the reducing end; this is the non-reducing end.1371

That is it- nice, basic structure.1375

Glucose units, down, up, down, CH2OH, CH2OH, oxygen is in the back right, oxygen back right, oxygen back right- this is a nice, good, very, very well-behaved polysaccharide.1378

We did not have to flip anything; we did not have to spin anything.1392

That is good; this is the Haworth projection that you see.1395

Now, of course, you know the hexose rings, they assume chair conformations.1401

They are not flat like this; they are not like benzene.1405

Benzene is a flat molecule, these are not.1408

I wanted you to see what this looks like in actual configuration, in actual conformation, I'm sorry, conformation.1410

These hexose rings actually assume chair conformations, and here is what the glycosidic bond looks like.1417

This right here is actually this right here.1425

So, we have our 1 and our 4 carbon, our 1 carbon, our 4 carbon, 1 carbon, 4 carbon, and, of course, it goes on like that.1429

You see this little stair step pattern, this is how it looks.1437

Now, again, it is going to be up to your teacher whether he or she wants you to draw it like this in this projection, or whether he or she actually wants to see at least 2 or 3 units in the chair conformation.1442

I will leave that up to your teacher, but again, what you want to notice is the arrangement, oxygen back right, oxygen back right; here is your CH2OH.1457

Notice, here, they actually wrote the C; here, it is just 2 lines coming together at a point, at a vertex.1466

So, that is a carbon; that is a carbon.1474

That is a carbon, nothing new here.1475

Equatorial, axial- that is what you have to watch out for.1478

OK, start with this projection, and then, go to this particular rendering, this particular representation.1482

OK, now, let's take a look at amylopectin.1490

I think that is going to be the next, yes; this is a little piece of amylopectin.1494

Let's go ahead and identify our 1,4.1499

So, we have our 1,4, 1,4 .1504

This is our glycosidic bond, glycosidic bond; and now, we have our 1 and 6.1507

There you go; that is your branch point.1514

At the no. 6 carbon of a particular glucose monomer, that oxygen has reacted with the anomeric carbon of another glucose, and it has started the chain, a second chain.1516

Now, this chain is going to go off in this direction, and then, this chain is going to go off in this direction; and they are going to parallel each other.1528

And, as you will see in a minute, they don't just parallel each other, they actually wind around each other in a helical pattern.1535

That is it; that is the only difference.1542

You have the 1,4 configuration, and in amylopectin, your branch points are at 1,6.1545

So, maybe a little further down the line, there is another 1,6.1550

That is it, alpha-(1,6).1555

This is alpha, because the hydroxy is pointing down.1558

There you go, and, of course, this is another representation of it with just a couple more.1562

Here, we have 3 and 1; here, we have 3 and 2.1569

You see our 1, our 4, our alpha-1, our 4.1572

This is alpha-1; this is our 6, and then, of course, it continues on.1577

This is alpha-(1,4), that is it.1581

This is amylopectin, nothing going on here; monomer, monosaccharide, disaccharide, now, it is polysaccharide.1585

What is important are the individual monomer units; if you understand those, you can build any polysaccharide you want.1592

That is the whole idea; that is what we want you to be able to do.1599

OK, so, now, let's take a look at...OK, here we go.1602

So, we talked about the actual amylopectin clusters.1610

This is amylopectin; this is a macroscopic.1615

We started over here; we have some chain, and then, this one branched off, and then it branched off again, and then it branched off again.1621

And then now, when the whole branching thing stopped, these 2 that were paralleling each other, now, they start to wind around each other in a coil.1628

What you end up with is, once everything is built, you end up with something that looks like this.1639

That is it; this is a nice cluster of amylopectin.1645

That is all.1649

This, right here, this is a detail of those 2 strands.1650

Once it branches off in the 1,6, they parallel each other, they actually start to wind around each other, so this is 1 strand, and this is another strand, and they intertwine.1653

That is it; they intertwine.1666

There is nothing in between them; they just intertwine.1668

It is like the backbone of the DNA, a nice helical pattern, and that is represented here.1671

Let me just write, this is an amylopectin, helix.1678

That is it, nothing strange happening here.1685

OK, let's actually, let's draw something by hand; let’s see.1690

Again, we want as much practice as possible.1698

Let's draw an alpha-(1,4) and an alpha-(1,6) of amylopectin just for a little practice.1705

Pretty much what we just saw, let's just draw it out by hand, so we know where to put everything.1718

OK, let's do our glucose down here.1728

Let's go 1,4.1733

This is going to be alpha-(1,4), so it is going to be like this, like that.1740

This is our 1,4 linkage, so this is alpha-1, and this is 4.1749

Let me go ahead and put that there, this, there, this, there, here.1755

I have got the CH2; this is going to be my 1,6.1763

Let me go ahead and put this as CH2OH.1767

OK, 1,6, this is the no. 6 carbon.1771

Let me use black.1776

This is our no. 6 carbon, and now, this is going to be connected to a - go back to red - another alpha-(1,6).1780

Alpha means that the hydroxy is below the ring.1794

It is going to look like this, and, of course, this is - nope, that is not there - this is glucose, so this is down.1798

This is up, and this is going to be off connecting that way, and chances are...you know what, I am going to go ahead and connect this one off too.1809

This is going to go that way, and that is going to be running off, and then, this is going to be CH2OH.1824

There you go; here, we have our nice amylopectin branch point, glucose, alpha-(1,4), glucose, alpha-(1,6).1831

This is the alpha-1; let me go ahead and erase these and write them in black.1843

This is the alpha-1, and this is the no. 4.1851

That is it; there should be no problem at this point.1855

Hopefully you have had a little bit of practice, and you should be able to just knock them out given the particular configuration at the glycosidic bond.1857

OK, let's see what else we can do.1866

OK, now, let's talk a little bit about glycogen.1871

Let me go ahead and...a page here.1874

Now, glycogen, let's see, you haven't eaten for a certain number of hours, and your body needs some energy.1878

Well, if your body doesn't have any energy in terms of the food that you put into it, it is going to go to its next readily available source of energy, and that is the glycogen that is stored in your cells, that is stored in your body, mostly in your liver.1892

That is the first place that it is going to go in order to break off glucose units and send those glucose units into the bloodstream and out to the other parts of the body, so that your body and brain can function.1907

That is it; glycogen is essentially just a readily available, very quick storage for available fuel that gets it into your body right away.1920

Glycogen is hydrolyzed - in other words, it is broken up - from the non-reducing ends, the left ends.1934

Remember we had that little cluster; well, I will draw it out in just a minute.1957

OK, now, since - excuse me - there are so many branches and we said the glycogen is more heavily branched than starch, several glucose monomers can be cut off simultaneously in order to supply the body with glucose, with individual glucose monomers.1962

Now, let's go ahead and draw what that looks like.2016

Let's do a little bit like a main chain, something like this.2019

So, I have got another branch here, maybe another branch, another branch, another branch, another branch.2024

I'm just going to draw a whole bunch of branches like this, like that, like that, like that.2030

Each one of those, at some point, it terminates; and what you have are these, you have glucose at the ends.2036

These are the non-reducing ends right here; of course, it is a lot more compact than this.2044

This is the reducing end right here; this is the reducing end.2049

Now, when your body needs glucose, glycogen has evolved to take on this particular structure because what it can do is, once it needs the glucose, it can just go and cut off these individual ones.2054

Instead of one long chain, where it has to go cut this one, then this one, then this one, then this one, then this one, then this one, it is going to take a certain amount of time.2070

Yes, enzymatic reactions are very, very quick, but still, it is going to take a certain amount of time; but if it can take a whole bunch of these off simultaneously, hundred of thousands of them, millions of them, and just deliver them into the body, for the time it takes to cut off one, well, it can cut off several hundred thousand, and deliver them into the body.2078

That is why glycogen has the structure that it has, highly branched, so it has a whole bunch of glucose monomers available to it all at once because you are going to need that fuel all at once.2100

That is what's happening.2113

OK, now, let's talk a little bit more about glycogen and concentration, glycogen, which is stored as insoluble.2115

That is the key word here, insoluble granules, and there is probably a picture of it in your book.2135

You will see a cell with the little dots, the little black dots.2141

Those are granules of actual glycogen, granules in the cytosol.2146

Cytosol is the intracellular fluid.2154

OK, so, glycogen which is stored as insoluble granules in the cytosol - excuse me - contributes nothing to the osmolarity of the cytosol because it is insoluble, it is solid.2158

In other words, it doesn't have, there aren't free particles of glycogen floating around in an aqueous environment; it is not dissolved.2182

Now, liver cells store glycogen equivalent to about 0.4M free glucose.2193

In other words, if I were to take all of the glucose, all of the glycogen, and break it up into individual monomers, the amount of glucose that is there actually accounts for about 0.4M because glucose is soluble; glycogen is not soluble.2218

Now, if glucose were stored as monomers, just sort of floating around in the cytosol, the osmolarity of the cytosol would go through the roof.2234

The osmolarity of the cell, well, 0.4M, the osmolarity, there are going to be so many more particles inside the cell than outside the cell.2265

It is going to cause the liquid to flow from outside the cell into the cell causing the cell to burst open.2281

OK, it caused fluid to flow into the cell and rupture it.2289

The body definitely knows what it is doing; it needs to have a supply of glucose, but it can't just have free glucose floating around in the cell, in the cytosol because then, the osmolarity of the cell would be so high that it would cause a difference in osmotic pressure inside and outside.2309

Osmosis would pull water into the cell, and the cell would just explode.2326

So, by storing it as insoluble glycogen, it is there.2332

It is insoluble, so it does not contribute anything to the osmolarity, but it is readily available; and the particular form of glycogen as such that all of those glucose monomers are available very, very quickly- fantastic, absolutely fantastic, extraordinary molecule, extraordinary molecule.2337

That is what's going on with glycogen and starch.2356

OK, thank you for joining us here at Educator.com2360

We will see you next time, bye-bye.2362

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