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Raffi Hovasapian

Raffi Hovasapian

Aqueous Solutions & Concentration

Slide Duration:

Table of Contents

I. Preliminaries on Aqueous Chemistry
Aqueous Solutions & Concentration

39m 57s

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

38m 53s

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

29m 1s

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

39m 11s

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

41m 33s

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

44m 19s

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

18m 45s

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

38m 19s

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

27m 14s

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

48m 28s

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

45m 18s

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

42m 47s

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

1h 2m 33s

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

49m 12s

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

54m 31s

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

50m 52s

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

51m 36s

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

1h 3m 36s

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

1h 7m 16s

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

41m 38s

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

44m 2s

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

56m 40s

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

20m 37s

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

51m 37s

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

51m 23s

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

54m 49s

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

1h 17m 46s

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

37m 6s

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

43m 32s

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

39m 25s

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

44m 15s

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

44m 23s

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

40m 22s

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

54m 55s

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

38m 51s

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

38m 20s

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

48m 36s

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

45m 51s

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

37m 6s

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

44m 32s

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

30m 8s

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

49m 46s

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

56m 34s

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

42m 12s

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

43m 32s

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

1h 1m 47s

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

59m 17s

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

39m 47s

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

41m 34s

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

34m 18s

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

42m 52s

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

36m 10s

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

49m 20s

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

44m 11s

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

48m 11s

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

45m 58s

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

33m 18s

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

40m 59s

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

39m 18s

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

36m 21s

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

47m 58s

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

41m 11s

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

36m 27s

Intro
0:00
Complex III
0:19
Complex III Overview
0:20
Complex III: Step 1
1:56
Complex III: Step 2
6:14
Complex IV
8:42
Complex IV: Cytochrome Oxidase
8:43
Oxidative Phosphorylation, cont'd
17:18
Oxidative Phosphorylation: Summary
17:19
Equation 1
19:13
How Exergonic is the Reaction?
21:03
Potential Energy Represented by Transported H⁺
27:24
Free Energy Change for the Production of an Electrochemical Gradient Via an Ion Pump
28:48
Free Energy Change in Active Mitochondria
32:02
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Lecture Comments (36)

1 answer

Last reply by: Professor Hovasapian
Thu Oct 13, 2016 6:16 AM

Post by Parth Shorey on October 5, 2016

How did you get the density of lactic acid?

1 answer

Last reply by: sandi imayeguahi
Mon Jun 6, 2016 2:25 PM

Post by sandi imayeguahi on June 6, 2016

how did you get the mass of malic acid at 37:23?

2 answers

Last reply by: Professor Hovasapian
Thu May 19, 2016 3:55 PM

Post by Michael Amin on May 18, 2016

Hi,

I was wondering what book can I use to supplement your lectures for biochemistry. Would appreciate your response!

Thanks,

1 answer

Last reply by: Professor Hovasapian
Sun Feb 7, 2016 11:40 PM

Post by Mohamed E Sowaileh on February 7, 2016

Professor Hovasapian,

From your respond to Mr. Apolonia, I understood that in order to have a full, solid comprehension in biochemistry we have to study physical chemistry, and without physical chemistry we may understand biochemistry but we may not have a very solid comprehension. Is that right ? Please correct me.

A pharmacy student.  

2 answers

Last reply by: Apolonia Gardner
Tue Nov 24, 2015 1:17 PM

Post by Apolonia Gardner on November 24, 2015

Hello,

I am a high school senior about to send off my applications for college. I am stuck on one thing – my intended major. Biology and chemistry have been my favorite courses throughout high school, and I would like to get a college degree that will enable me to perform research with viruses. My lifetime goal is to find a cure for a disease. From your experience, what undergraduate major should I shoot for? Biochemistry? Microbiology? Molecular Biology? Immunology? Chemical Biology? Organic Chemistry? Pharmaceutical Science? Any guidance is appreciated.

3 answers

Last reply by: Lilly Anne
Wed Sep 2, 2015 3:26 PM

Post by Lilly Anne on September 1, 2015

Hello Professor,

I am taking a Biochemistry I course this semester at my university. I took Organic Chemistry years ago and i don't have as much memory of it. I am worried that i won't succeed in Biochemistry because i don't have a recent excellent understanding of biochemistry.

What topics in organic chemistry would you recommend i review and study in order to succeed in Biochemistry I?

Thank You

Thank You

0 answers

Post by taoheed kasumu on May 9, 2015

is there a possibility that your slides can be typed and presented like the organic chemistry tutor? I feel like it makes it much faster to present the material!

1 answer

Last reply by: Professor Hovasapian
Fri Feb 27, 2015 1:31 AM

Post by Robert Bright on February 26, 2015

i love your hair!

1 answer

Last reply by: Professor Hovasapian
Sun Feb 1, 2015 6:19 PM

Post by Okwudili Ezeh on January 31, 2015

How come there are no lessons on DNA replication and transcription?

2 answers

Last reply by: Zachary McCoy
Sat Nov 1, 2014 6:11 PM

Post by Crystal Rosenbrook on September 18, 2014

Is there any way to increase the playback speed of the videos?

2 answers

Last reply by: James Plumb
Wed Aug 13, 2014 2:21 AM

Post by James Plumb on August 8, 2014

This questioned doesn't have to due with this lecture, but my question is if you had a more concrete date on the release of physical chemistry? Thank you.

1 answer

Last reply by: Professor Hovasapian
Tue Nov 5, 2013 2:37 PM

Post by robina saeed on November 5, 2013

Hello Professor,

I am starting Biochemistry this month. I am done with General Chemistry. I have no Organic Chemistry.  Do I need Biology to do really well in Biochemistry?

Take Care,
Robina Saeed

1 answer

Last reply by: Professor Hovasapian
Fri Aug 2, 2013 2:49 PM

Post by robina saeed on August 2, 2013

Hi Professor
Thanks for the earlier response. I have one more question. I have had a full year of general chemistry.  Do I need organic chemistry to begin this course?  Never had organic chemistry.

Thanks,
Robina

1 answer

Last reply by: Professor Hovasapian
Sun Jul 28, 2013 11:52 PM

Post by robina saeed on July 28, 2013

Hi Professor
What course work do you recommend I review before starting this course?  General Chemistry or Organic Chemistry?

0 answers

Post by Leili Reza on March 4, 2013

great

1 answer

Last reply by: Professor Hovasapian
Mon Feb 18, 2013 1:28 AM

Post by Basil K on February 15, 2013

Really excited to start on these lectures! You are an excellent teacher Professor Hovasapian!

Related Articles:

Aqueous Solutions & Concentration

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
  • Aqueous Solutions and Concentration 0:46
    • Definition of Solution
    • Example: Sugar Dissolved in Water
    • Example: Salt Dissolved in Water
    • A Solute Does Not Have to Be a Solid
    • A Solvent Does Not Have to Be a Liquid
    • Covalent Compounds
    • Ionic Compounds
    • Example: Table Sugar
    • Example: MgCl₂
    • Expressing Concentration: Molarity
  • Example 1 14:47
    • Example 1: Question
    • Example 1: Solution
    • Another Way to Express Concentration
  • Example 2 24:00
    • Example 2: Question
    • Example 2: Solution
    • Some Other Ways of Expressing Concentration
  • Example 3 29:30
    • Example 3: Question
    • Example 3: Solution

Transcription: Aqueous Solutions & Concentration

Hello and welcome to Educator.com and welcome to the first lesson of Biochemistry.0000

Biochemistry is absolutely an extraordinary, extraordinary class.0006

There is a lot of information and all of the information is absolutely exciting.0012

Before we actually jump into the biochemistry with proteins and lipids and carbohydrates and metabolism, what we want to do is do just a little bit of a general chemistry review all of the things that are going to be very, very important.0018

Now, you've seen most of these things before but it may have been a while since you've actually worked with them.0031

For the first couple of lessons, we're just going to do a nice chemistry review just to get everything going again and then we'll jump into the biochemistry.0035

Let's get started and welcome again.0043

OK. We're going to start off by discussing aqueous solutions and the notion of concentrations.0048

An aqueous solution, the reason we're discussing this is because the body of chemistry that takes place in the body, takes place in an aqueous solution - in water; we're mostly just water.0055

And it's just a whole bunch of molecules that are dissolved in that water running into each other and doing the things that they do.0070

Because this is biochemistry, the chemistry of biological systems, the chemistry of biological molecules, all of the chemistry that you learned in general chemistry regarding aqueous solutions, all of it absolutely applies here.0073

Let's go ahead and start with our definition of solution and we'll work our way forward.0089

Solution is just a solute dissolved in a solvent.0099

There are two things, you have the solvent and then you have the solute, the thing that's actually dissolved in it.0113

For biochemistry, it works out really, really great because the only solvent that we're concerned with is water, thus, aqueous.0119

If you remember from organic chemistry, you're going to have all kinds of solvents.0124

You can have hexane, you can have ethyl acetate, you can have all kinds of things alcohol, but for biochemistry, its water, so it makes our life that much simpler.0130

Some examples of solutions... Let's see what we've got.0140

We have sugar dissolved in water. That is a sugar solution, sugar dissolved in water.0145

The sugar is the solute and sure enough, the water is the solvent.0155

H2O is the solvent.0164

In this particular case, you have a solid, the sugar crystals, and the solvent happens to be a liquid.0167

Now, it doesn't have to be this way.0172

A solute does not have to be a solid and a solvent doesn't have to be a liquid.0174

It just turns out that way most of the time and certainly in our case.0179

Let's see. How about another example? Let's take salt dissolved in water so a salt solution.0185

When a salt is dissolved in water, again, the salt is your solute and H2O is again, the solvent.0194

Oops, not solute. What we have is solvent. OK.0209

Now, as I said before, a solute does not have to be a solid.0218

A solute does not have to be a solid.0223

It just happens to be most of our experience from general chemistry, organic chemistry and just normal day to day stuff.0233

Most solutes happen to be solid because we dissolve them in something.0240

We see the crystals just sort of disappear as the solution is created but it doesn’t have to be that way and in fact we have a daily example of that- carbonated water.0244

Carbonated water or soda is actually just CO2 gas dissolved in water so a solute is a gas.0255

Let me write this out... carbonated water.0265

In this particular case, the CO2 is the solute.0271

It is a gas and H2O is the solvent. H2O is the solvent.0277

Now, in this particular case, in order to make sure that the CO2 actually stays dissolved in the water to create the carbonic acid solution - the carbon dioxide solution, we have to put it under pressure.0284

Which is why when you pop the can, the carbon dioxide escapes and that's the bubbles rising. Ok.0295

Now the solvent itself... the solvent does not have to be a liquid.0304

Does not have to be a liquid...0316

This notion of a solution is actually a very, very broad definition.0321

It's when something is dissolved in another.0325

In other words, when you get what looks like a completely homogeneous thing where you can't see the individual particles of the solute to the solvent, it just looks like one thing.0327

The solvent does not have to be a liquid, but for us, we don't have to worry about that, our solvent is water.0337

OK. So let's see what we've got here. OK.0344

Sugar and salt, they both dissolve in water but do they dissolve the same way?0350

Sugar crystals, salt crystals, when you're a kid, it looks like they behave the same way.0355

It isn't until you actually get to chemistry that you discover that the dissolving process is actually completely different and what is going on inside the solution, the chemistry is entirely different.0359

Let's write that out.0372

Sugar and salt both dissolve the same way, actually, they don't dissolve the same way, they dissolve.0375

Question is "Do they dissolve the same way?" Sorry about that.0394

Both dissolve but do they do so the same way, and the answer is no, they do not.0397

Now, covalent compounds...0415

Covalent compounds are basically compounds that are made of non-metal non-metal bonds sharing of electrons.0420

Covalent compounds...they dissolve.0429

When they do so, we say that they dissolve. The example of that is sugar.0433

Sugar is a covalent compound even though it has some hydroxy groups where some of the Hs can actually be removed.0437

It is actually is considered a covalent compound because you have carbons bonded to other carbons.0444

You have carbons bonded to oxygens. You have oxygens bonded to hydrogens.0448

These are single bonds, single and double bonds.0453

When these dissolve, they just dissolve.0457

Now, salts, or ionic compounds...I'll write them as ionic compounds and of course the word "salt" is a generic term for any ionic compound.0459

I'll put salt in parenthesis.0470

Now, when salts dissolve... When these dissolve, because not all salts dissolve...Do you remember when you were doing solubility product?0473

If you take sodium chloride which is normal table salt, put it in the water, yes it'll dissolve up to a certain point.0483

If you put silver chloride into water, it'll just sink to the bottom.0489

Remember precipitation? Precipitation is salts that don't dissolve in water.0493

Now, salts when they do dissolve, they dissociate.0497

This is very, very important...they dissociate.0505

In other words, dissociation means they separate into individual ions, into individual free ions.0509

This is very, very important.0522

When a covalent compound...you can put it in there and you are not creating an electrically conductive solution.0524

But, when salt dissolves, like sodium chloride, it breaks up into Na+ and Cl- ions floating around.0532

Well, now, this solution actually will conduct electricity because you have positive and negative charges floating around.0539

The chemistry, the behaviour of the solution, is entirely different even though they actually look the same.0545

That is what's important. OK.0550

Let's just take a table sugar. Let's just sort of see what this looks like.0552

C12H22O11 - this is sucrose as a solid.0557

When we dissolve it in the water, what we end up with is C12H22O11 aqueous.0565

This aq tells us that it is dissolved.0573

This is solid, drop it in water, it is dissolved. OK.0576

That is what this aq means.0580

Let me go ahead and write that.0582

aq means dissolved. It means that is surrounded.0591

Each individual molecule of sucrose has separated from the crystal and is now surrounded by a bunch of water molecules which is why you can't see the individual crystals of the water anymore.0594

It is now a sugar solution, not a sugar crystal.0604

OK. Notice. One molecule of sugar produces one molecule of aqueous sugar.0608

1mol of the sugar crystals will produce 1mol of free individual particles.0616

These particles right here... this aqueous. That means these individual sugar molecules are floating around freely as molecules.0622

Nothing has come apart. The carbon hydrogen oxygen bonds have not broken.0630

It's just a whole molecule just floating around freely whereas here, each molecule is arranged in a crystal.0634

Now, let's go ahead and take something like magnesium chloride, a salt.0642

Magnesium chloride, an ionic compound...This is a solid.0647

When I drop this in water, what happens is it dissociates.0650

It completely comes apart into its free ions.0655

It separates into a Mg2+ ion floating around and you have two chloride ions floating around so what happens is, one unit of these...0658

We don't speak about ionic compounds as molecules because this is not really a covalent bond.0668

This is a positive charge and a negative charge that are stuck together.0674

It's a very strong bond but it's not covalent so we don’t talk about it as a molecule.0677

You can say, you can call it a unit.0682

I mean, it's not going to be the end of the world if you call it a molecule but just to let you know.0684

So 1 unit of magnesium chloride produces three particles: one magnesium ion particle and two chloride ion particles.0688

This is very, very important as you'll see in a minute.0695

Let's go ahead and put aq and aq.0701

In general, when you have ions on the right side of the arrow on an equation, the presumption is that they are aqueous, that they're dissolved,0705

unless you are specifically speaking about a gaseous phase, but we're not.0712

Everything is aqueous chemistry for us so we don't need to put the aq but I'll put them here however, in the future, I will not.0715

OK. So notice.0723

One unit of MgCl2, of the magnesium chloride, it produces three free particles.0726

That's it. That's what's going on here. Three free particles floating around in a solution.0741

Floating around in a solution...0747

Covalent compounds dissolve salts. When they do dissolve they're actually dissociating.0753

OK. Now let's talk about the notion of concentration.0760

If I take 1g of salt and I drop it into 100mL of water versus if I take 20g of salt and I drop it into 100mL of water, clearly, there is going to be a hell of a lot more salt.0765

The concentration of the solution is going to be larger in the second one. There's more salt in it.0779

The volume of the solution is the same. It still stays 100mL but I have 1g and 120g in the other.0785

I need a numerical method for differentiating between the two.0791

We call that concentration.0796

Concentration, there's a whole bunch of ways to express concentration. We're going to be concerned with two of them: molarity and percent by mass.0798

Those are the ones that I'm actually going to introduce and do examples with.0806

However, for the most part, we're really only going to be concerned with molarity - moles of solute per liters of total solution.0808

OK. So expressing concentration... Let me go ahead and put a little line here.0816

Expressing concentration... OK.0829

The first way and the primary way is something called molarity and it is expressed with a capital M.0834

Molarity is defined as the moles of solute divided by the liters of solution.0840

This is the final volume0855

Now, you remember I said that the solute doesn't have to be a solid.0857

If I take a liquid solute like liquid glucose and I drop it into liquid water, well, if I take 10mL of the liquid glucose and put it into 100mL of liquid water, now the total volume of my solution is 110mL.0860

It's not 100mL. So molecules take up volume.0875

This is liters of total solution. This is just moles of solute the things that you add.0880

It's very, very important to keep this thing straight.0885

OK. So let's do an example with molarity.0887

Again, it's all about the examples, all about working with these things using your intuition, everything that you already know from previous classes.0893

We have 7mL of lactic acid dissolved in 130mL of H2O.0902

What is the molarity of the lactic acid?0923

What is the molarity of this lactic acid solution?0928

OK. Well we'll try to write our definition.0941

The molarity is going to equal the moles of lactic acid divided by the liters of solution.0944

That is what we need.0954

We need this number, the moles of lactic acid.0956

We need the liters of solution and then we’re going to do the division and that will give us our concentration in mol/L.0958

That's the unit- mol/L.0965

Let me write that here: moles per liter and it is symbolized with a capital M.0967

I actually prefer to see my entire unit, this M thing is always...hasn't confused me but I like to work with my entire unit. I don't like anything to be hidden but that’s just a personal preference.0975

OK. So, before I do that, this is biochemistry and you know our examples.0986

We're going to try our best to use as many biological molecules as possible.0990

As we do that, I'm going to just draw out the structures of these things just so you get accustomed to seeing them and that's how we develop a sense of familiarity with these biomolecules and they are going to get larger and larger and larger.0996

So, lactic acid looks like this.1009

I'm going to do a straight carbon structure.1012

H and CH3 and we have an OH there...1020

We have three carbons: We have a carbonyl group, this is a carboxylic acid group, this is an alpha-hydroxy acid, actually, and it's an alpha-hydroxy acid.1026

Remember, this carbonyl carbon, this is the carbonyl carbon right here, the one that is attached to the double bond.1034

Let me do this in red.1039

That is the carbonyl carbon. This is called the alpha carbon and this is called the hydroxy group.1041

This is called an alpha hydroxy acid, an alpha hydroxy carboxylic acid - three carbons long.1047

This is lactic acid.1053

This is what develops in your muscles when you start to get sore, when you exercise really, really fast and the body starts to metabolize under anaerobic conditions without oxygen.1055

The by-product is actually lactic acid.1070

That's what you feel when your muscles start to get really, really sore when your exercising really, really fast.1073

OK. Now let me see what were we doing?1079

We want the molarity of this lactic acid solution.1082

OK. I'm going to keep it in red.1084

Let's do moles of... So, we need the moles of lactic acid.1087

Well, we have the milliliter of lactic acid. That is what they give us.1096

We want the moles of lactic acid.1102

How can I go from milliliter to moles?1105

Well, I know that I can go from grams of lactic acid to moles via the molar mass and I can go from milliliters to grams via the density.1107

That's my solution path. From milliliters, I'm going to go to grams and then from grams, I'm going to go to moles.1121

This is density and this is molar mass.1128

OK. Now, I look up the molar mass for lactic acid. I look up the density for lactic acid.1131

If they don't give it to me in the problem, and there is no guarantee that you're going to be given it to the problem, part of the idea is to use your resources whether they be computer resources or book resources to find the things that you need.1138

It is really, really important to be able to do that.1150

There are tables and it's very important that you become adept at utilizing your resources because there is no guarantee in real life.1152

You are just going to be presented with the problem. You have to look up these things.1162

When we look things up, the density of lactic acid is 1.209g/mL and of course I hope you will confirm this for me because I could have read it wrong, myself.1167

And, the molar mass of lactic acid is 90.08g/mol1181

We have 7mL of lactic acid times 1.209g/mL times 1mol happens to be 90.08g.1193

Now, of course, gram cancels gram, milliliter cancels milliliter and what we're left with is 0.0939mol of lactic acid.1211

You know what, I'm going to write this up. I'm just going to note moles of lactic, I'm just going to put lactic.1226

OK. Now we have the number of moles. We have the numerator, we have that.1232

Now we need the liters of solution.1238

Liters of solution...1241

OK. Well, this one is really easy.1244

We had 7mL of lactic acid.1246

We have 130mL of H2O. Both of them are liquid.1251

Remember what we said: liquid solute, liquid solvent, just add the liquids.1256

The total volume of the solution is going to be 137mL which is equivalent to 0.137L.1259

Because again, liters, moles per liter, that's the definition.1271

OK. Now, let's just go ahead and solve the problem.1275

I'll do it on the next page here.1278

So, molarity... The concentration is equal to 0.0939mol of lactic acid divided by 0.137L, 137mL, what you get is 0.686mol/L or 0.686M, molarity. There you go.1281

Either one is absolutely fine.1312

That's our concentration in moles per liter.1314

In this particular situation, in one liter of solution, you have 0.686mol. OK.1316

Now, let's introduce another expression, another way of expressing concentration.1324

This is presented by mass. This is also very, very popular.1329

You'll see this a lot on bottles at the grocery store and stuff.1331

They're expressed in terms of mass.1334

Let me go back to black here.1338

Another way to express concentration is percent by mass. OK.1344

Now, percent by mass, you'll see it this way, %m/m. That's what this symbol is for- percent by mass.1368

The definition is this: It's the mass of the solute.1380

Like any percent, it's always the part over the whole times a hundred. It's a fraction times a hundred.1387

That's what a percent is. A percent is just a fraction that has turned into a number that's a little easier to handle.1392

That's the only reason a percent exists.1398

You actually don't really need that whole multiplying by a hundred.1400

The decimal is just fine. But I guess some people just prefer numbers that are not pure decimals. OK.1404

Mass of solute over total mass of solution...1410

In other words, if I had a solution once I've made it, let's say a sugar solution that weighs 100g and of that 100g, if 5g of sugar are floating around in there, 5g of some solid sugar, what I have is 5 over 100 that is 5% sugar solution.1419

That is what this is. All percentages are just part over the whole, the part over the whole.1436

OK. Let's do an example.1441

This is going to be example 2.1446

What is the percent by mass, the %m/m of the lactic acid solution in the previous example?1451

OK. Well, we need of course the...let's do this in red again.1479

We need the mass of the solute. We need the total mass of the solution. OK.1485

Well, the mass of the lactic acid... so the mass of the lactic acid, that's just going to be the 7mL times its density.1490

We don't want to go all the way to moles so we're going to stop with grams times 1.209g/mL and when we do that we get 8.463g1501

That is the mass of the lactic acid. We have our numerator.1517

Now, total mass...1522

Well, total mass...What is our total mass?1524

Our total mass is the 8.463g of the lactic acid plus the mass of the water.1532

Well, water was 130mL. They gave it to us in volume.1542

Well, the density of water, normally, we just take it as 1g/mL so 130mL of water weighs 130g.1545

So, we have a total of 138.463 and I sure hope that you're confirming my Mathematics. I'm notorious for arithmetic mistakes.1555

OK. Well there we go. We're done.1560

So, the percent by mass of this solution is equal to 8.463g divided by...1574

Oh look at these crazy lines, can't have that. It tends to happen down at the bottom of the page so I think what I am going to do is I'm going to go ahead and move on to the next page because I don't want these crazy lines all over the place.1586

Let's try this again. So, percent by mass is equal to 8.463g of lactic acid divided by 138.463g of solution, and of course whenever we're dealing with the percent, the percent doesn’t have a unit.1598

Gram needs to cancel gram. OK. That's the whole idea...times 100 and when I do the Mathematics, I get 6.11%.1624

Our lactic acid solution was 0.686mol/L. It's 6.11%m/m.1638

That means if I had 100g of this lactic acid solution, 6.11% by mass is made up of lactic acid.1646

That's what this means. So, two ways of expressing concentration, but again, the one that we're going to be concerned with, most of the time, is going to be molarity- moles per liter.1655

And you already know that from chemistry. Most of the time, concentration, molarity is what we use. OK.1664

Well, let’s see what we've got.1673

I'm just going to list a couple of the other ways that concentration is expressed but we’re not going to be doing any samples with them because they're not going to be important for our purposes but I'd like you to know them. Ok1675

I'll go back to black here. OK.1685

Some other ways of expressing concentration had at some point or other, you certainly have heard of these or you will be hearing about them some other time in your career.1693

One of the ways is something called molality, and molality comes up when we talk about colligative properties of boiling point elevation, freezing point depression.1712

We're not going to be concerned with molality.1721

There's something called mole fraction, very, very important and again, a fraction is always the same thing. It's a part of the whole.1724

We did percent by mass. There is also something called percent by volume so it's usually designated as %v/v, I'll just go ahead and write the words out - percent by volume.1732

If I have a 100mL of solution, how many milliliters of that, what volume of that is actually the solute?1748

Percent by mass and percent by volume are two different numbers- they are not the same thing.1755

They might happen to be that same thing coincidentally but they're not the same thing.1760

And, there are other ways, I'm sure.1765

OK. Let's do another example here.1770

See if we can combine our concentration things.1777

A biochemist finds a bottle that a colleague has left at his bench that reads L-Malic 8.66%m/m.1784

OK.1832

What is this solution's molarity?1838

Molarity...1844

A biochemist goes to his colleague's bench and he finds this bottle that says L-Malic acid 8.66%m/m.1849

He knows that it is a Malic acid solution 8.66% by mass.1855

He wants to know what the molarity is, what is this solution’s molarity. OK.1859

In this particular case, we are going to be going from one expression of concentration to another. OK.1864

Malic acid...1869

I told you that we're going to be dealing with biological molecules so let me go ahead and draw the structure of malic acids so you see this one.1872

OK. Let's see. Shall I do it...That's fine, I'll just do it over here. OK.1880

So C,C,C,C, we have hydroxy there and then we have a wedge here.1886

Shall I put...that's fine...I'll go ahead and put the Hs in and then of course we have this.1896

So, this is malic acid. It has four carbons. It is a dicarboxylic acid. There is a carboxylic acid on one end.1902

There is a carboxylic acid on the other end and, it is also an alpha hydroxy acid because on the alpha carbon to one of the ends, there is a hydroxy and this wedge just means that it's actually coming out at us.1910

Biological molecules have a handedness, remember chirality from organic chemistry?1923

There is an L-Malic acid and there is a D-Malic acid.1928

In this particular case, it's L-Malic acid, so if we write it like this, it's actually coming out at us.1933

You will also see just for...you will also see it this way- the regular line structure instead of this.1940

It's up to you how you want to draw, whatever is most comfortable for you.1949

I tend to draw these, I don’t really care for this very much, again, because I like to see my carbons, I like to see what I'm working with.1953

Even after all these years, I still just feel most comfortable doing it this way but of course in the books, you know you're going to see it like this, so you certainly need to be able to recognize it.1960

That is the line structure for malic acid.1974

Malic acid is what gives green apples their tartness.1977

A very, very important biological molecule as you'll find out later in the course when we discuss the citric acid cycle. OK.1981

8.66% by mass means the following.1988

They gave us the number 8.66% - that means this.1997

It means the mass of the malic acid, I'll just call it malic, over the mass of solution times 100 is equal to 8.66.2001

They gave us this. This is the definition, so, I want to start with this.2019

I'm going to work my way back.2023

OK. Now let's ask ourselves what are these that we want and let's do this in red.2027

We want molarity.2030

It's really, really important that you do know what are these that you want.2032

I want molarity, so here's...so, molarity it means I want the moles of malic acid over the total liters of solution.2037

I need those two numbers. I need this and I need this.2043

How can I get that based on the information that I have? OK. Let's take a look at this.2057

The first thing I'm going to do is, I need the moles of malic, liters of solution.2063

The one that's quickest here...what I'm just going to do is I'm going to just...Well, let me write out what the biochemist did.2068

The biochemist measures the volume of the solution.2075

In other words, he just takes it and pours in into a graduated cylinder to see what the volume is in order to get that number.2084

measures the volume of solution to be 17.5mL.2093

In that bottle, he has 17.5mL.2104

He has the volume, he has the denominator, half our problem is done.2108

Now, we just need to find the moles of malic acid. OK.2111

That's the second part.2114

How do we find the moles of malic acid?2116

Well, I need the moles of malic acid and I know that I can get the moles of malic acid from the grams of malic acid, from the mass, from the grams of the malic acid.2119

And my conversion factor is the molar mass. Well molar mass is easy, I just looked it up. OK.2134

So the biochemist measures the mass of the solution. OK.2141

The biochemist measures the mass of the solution.2152

He puts it on the scale and he actually measures it or actually, he takes a glass vile.2156

He takes its mass. He empties the contents into that vile and then he takes that mass.2162

He subtracts the mass of the vile that he knows the mass of and he has the mass of the solution.2167

The biochemist measures the mass of the solution to be 17.75g. OK.2173

Now he has the mass of the solution.2191

Well, we need the mass of the malic acid.2195

Well, we just said earlier, the mass of malic acid divided by the mass of the solution, the total mass which is now 17.75g x 100 = 8.66.2197

We have all these numbers so now we have this equation.2216

We just do a little bit of algebra to find the mass of malic acid and that turns out to be....2218

Actually, let me do it underneath here. Sorry about that.2220

After a little bit of rearranging and a little bit of algebra, the mass of malic acid happens to be 1.537g.2234

There you go. I have 1.537g, that's my mass of malic acid.2246

I have my liters of solution - 17.5mL.2250

Now, I just have to make sure the units are appropriate.2253

Oh, I'm sorry, moles of malic acid.2258

This is my mass of malic acid. I still have to do the conversion to moles.2262

Let's do that.2265

I've got 1.537g of malic times 1mol and again, I'll look it up if the problem doesn't give it to me - 134.09g.2268

This is just basic stoichiometry, then I get 0.0115mol of malic acid.2283

OK. We are done.2293

The molarity equals 0.0115mol of malic acid divided by, and we said we had 17.5mL, right? OK. 17.75mL, the unit has to be liters so move the decimal over 3 times, we get 0.0175L2295

And when we do that, we get 0.066M or 0.66mol/L, my preferred expression for that unit.2329

That's it.2343

We were given a concentration in one expression, percent by mass, we wanted molarity, we wrote down the definition of molarity and we just took a look to see what we needed.2345

We needed moles of solute, we needed liters of solution.2356

Well, the liters of solution is easy, you just measure the volume so that it gives you that.2360

We use the information of percent by mass to recover the mass of the solute, the malic acid, and then from the mass, we use molar mass to get to moles.2363

These are the kinds of things that you want to do. Write it all down.2372

See some sort of a solution path.2376

There is only a handful of definitions. Molarity is moles per liter. Percent by mass is mass of the solute divided by total mass times 100.2379

Everything should come together really, really nicely.2388

OK. Thank you for joining us for our first lesson of biochemistry. We look forward to seeing you again. Take care.2392

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