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Dr. Carleen Eaton

Dr. Carleen Eaton

Photosynthesis

Slide Duration:

Table of Contents

I. Chemistry of Life
Elements, Compounds, and Chemical Bonds

56m 18s

Intro
0:00
Elements
0:09
Elements
0:48
Matter
0:55
Naturally Occurring Elements
1:12
Atomic Number and Atomic Mass
2:39
Compounds
3:06
Molecule
3:07
Compounds
3:14
Examples
3:20
Atoms
4:53
Atoms
4:56
Protons, Neutrons, and Electrons
5:29
Isotopes
10:42
Energy Levels of Electrons
13:01
Electron Shells
13:13
Valence Shell
13:22
Example: Electron Shells and Potential Energy
13:28
Covalent Bonds
19:52
Covalent Bonds
19:54
Examples
20:03
Polar and Nonpolar Covalent Bonds
23:54
Polar Bond
24:07
Nonpolar Bonds
24:17
Examples
24:25
Ionic Bonds
29:04
Ionic Bond, Cations, Anions
29:19
Example: NaCl
29:30
Hydrogen Bond
33:18
Hydrogen Bond
33:20
Chemical Reactions
35:36
Example: Reactants, Products and Chemical Reactions
35:45
Molecular Mass and Molar Concentration
38:45
Avogadro's Number and Mol
39:12
Examples: Molecular Mass and Molarity
42:10
Example 1: Proton, Neutrons and Electrons
47:05
Example 2: Reactants and Products
49:35
Example 3: Bonding
52:39
Example 4: Mass
53:59
Properties of Water

50m 23s

Intro
0:00
Molecular Structure of Water
0:21
Molecular Structure of Water
0:27
Properties of Water
4:30
Cohesive
4:55
Transpiration
5:29
Adhesion
6:20
Surface Tension
7:17
Properties of Water, cont.
9:14
Specific Heat
9:25
High Heat Capacity
13:24
High Heat of Evaporation
16:42
Water as a Solvent
21:13
Solution
21:28
Solvent
21:48
Example: Water as a Solvent
22:22
Acids and Bases
25:40
Example
25:41
pH
36:30
pH Scale: Acidic, Neutral, and Basic
36:35
Example 1: Molecular Structure and Properties of Water
41:18
Example 2: Special Properties of Water
42:53
Example 3: pH Scale
44:46
Example 4: Acids and Bases
46:19
Organic Compounds

53m 54s

Intro
0:00
Organic Compounds
0:09
Organic Compounds
0:11
Inorganic Compounds
0:15
Examples: Organic Compounds
1:15
Isomers
5:52
Isomers
5:55
Structural Isomers
6:23
Geometric Isomers
8:14
Enantiomers
9:55
Functional Groups
12:46
Examples: Functional Groups
12:59
Amino Group
13:51
Carboxyl Group
14:38
Hydroxyl Group
15:22
Methyl Group
16:14
Carbonyl Group
16:30
Phosphate Group
17:51
Carbohydrates
18:26
Carbohydrates
19:07
Example: Monosaccharides
21:12
Carbohydrates, cont.
24:11
Disaccharides, Polysaccharides and Examples
24:21
Lipids
35:52
Examples of Lipids
36:04
Saturated and Unsaturated
38:57
Phospholipids
43:26
Phospholipids
43:29
Example
43:34
Steroids
46:24
Cholesterol
46:28
Example 1: Isomers
48:11
Example 2: Functional Groups
50:45
Example 3: Galactose, Ketose, and Aldehyde Sugar
52:24
Example 4: Class of Molecules
53:06
Nucleic Acids and Proteins

37m 23s

Intro
0:00
Nucleic Acids
0:09
Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA)
0:29
Nucleic Acids, cont.
2:56
Purines
3:10
Pyrimidines
3:32
Double Helix
4:59
Double Helix and Example
5:01
Proteins
12:33
Amino Acids and Polypeptides
12:39
Examples: Amino Acid
13:25
Polypeptide Formation
18:09
Peptide Bonds
18:14
Primary Structure
18:35
Protein Structure
23:19
Secondary Structure
23:22
Alpha Helices and Beta Pleated Sheets
23:34
Protein Structure
25:43
Tertiary Structure
25:44
5 Types of Interaction
26:56
Example 1: Complementary DNA Strand
31:45
Example 2: Differences Between DNA and RNA
33:19
Example 3: Amino Acids
34:32
Example 4: Tertiary Structure of Protein
35:46
II. Cell Structure and Function
Cell Types (Prokaryotic and Eukaryotic)

45m 50s

Intro
0:00
Cell Theory and Cell Types
0:12
Cell Theory
0:13
Prokaryotic and Eukaryotic Cells
0:36
Endosymbiotic Theory
1:13
Study of Cells
4:07
Tools and Techniques
4:08
Light Microscopes
5:08
Light vs. Electron Microscopes: Magnification
5:18
Light vs. Electron Microscopes: Resolution
6:26
Light vs. Electron Microscopes: Specimens
7:53
Electron Microscopes: Transmission and Scanning
8:28
Cell Fractionation
10:01
Cell Fractionation Step 1: Homogenization
10:33
Cell Fractionation Step 2: Spin
11:24
Cell Fractionation Step 3: Differential Centrifugation
11:53
Comparison of Prokaryotic and Eukaryotic Cells
14:12
Prokaryotic vs. Eukaryotic Cells: Domains
14:43
Prokaryotic vs. Eukaryotic Cells: Plasma Membrane
15:40
Prokaryotic vs. Eukaryotic Cells: Cell Walls
16:15
Prokaryotic vs. Eukaryotic Cells: Genetic Materials
16:38
Prokaryotic vs. Eukaryotic Cells: Structures
17:28
Prokaryotic vs. Eukaryotic Cells: Unicellular and Multicellular
18:19
Prokaryotic vs. Eukaryotic Cells: Size
18:31
Plasmids
18:52
Prokaryotic vs. Eukaryotic Cells
19:22
Nucleus
19:24
Organelles
19:48
Cytoskeleton
20:02
Cell Wall
20:35
Ribosomes
20:57
Size
21:37
Comparison of Plant and Animal Cells
22:15
Plasma Membrane
22:55
Plant Cells Only: Cell Walls
23:12
Plant Cells Only: Central Vacuole
25:08
Animal Cells Only: Centrioles
26:40
Animal Cells Only: Lysosomes
27:43
Plant vs. Animal Cells
29:16
Overview of Plant and Animal Cells
29:17
Evidence for the Endosymbiotic Theory
30:52
Characteristics of Mitochondria and Chloroplasts
30:54
Example 1: Prokaryotic vs. Eukaryotic Cells
35:44
Example 2: Endosymbiotic Theory and Evidence
38:38
Example 3: Plant and Animal Cells
41:49
Example 4: Cell Fractionation
43:44
Subcellular Structure

59m 38s

Intro
0:00
Prokaryotic Cells
0:09
Shapes of Prokaryotic Cells
0:22
Cell Wall
1:19
Capsule
3:23
Pili/Fimbria
3:54
Flagella
4:35
Nucleoid
6:16
Plasmid
6:37
Ribosomes
7:09
Eukaryotic Cells (Animal Cell Structure)
8:01
Plasma Membrane
8:13
Microvilli
8:48
Nucleus
9:47
Nucleolus
11:06
Ribosomes: Free and Bound
12:26
Rough Endoplasmic Reticulum (RER)
13:43
Eukaryotic Cells (Animal Cell Structure), cont.
14:51
Endoplasmic Reticulum: Smooth and Rough
15:08
Golgi Apparatus
17:55
Vacuole
20:43
Lysosome
22:01
Mitochondria
25:40
Peroxisomes
28:18
Cytoskeleton
30:41
Cytoplasm and Cytosol
30:53
Microtubules: Centrioles, Spindel Fibers, Clagell, Cillia
32:06
Microfilaments
36:39
Intermediate Filaments and Kerotin
38:52
Eukaryotic Cells (Plant Cell Structure)
40:08
Plasma Membrane, Primary Cell Wall, and Secondary Cell Wall
40:30
Middle Lamella
43:21
Central Cauole
44:12
Plastids: Leucoplasts, Chromoplasts, Chrloroplasts
45:35
Chloroplasts
47:06
Example 1: Structures and Functions
48:46
Example 2: Cell Walls
51:19
Example 3: Cytoskeleton
52:53
Example 4: Antibiotics and the Endosymbiosis Theory
56:55
Cell Membranes and Transport

53m 10s

Intro
0:00
Cell Membrane Structure
0:09
Phospholipids Bilayer
0:11
Chemical Structure: Amphipathic and Fatty Acids
0:25
Cell Membrane Proteins
2:44
Fluid Mosaic Model
2:45
Peripheral Proteins and Integral Proteins
3:19
Transmembrane Proteins
4:34
Cholesterol
4:48
Functions of Membrane Proteins
6:39
Transport Across Cell Membranes
9:52
Transport Across Cell Membranes
9:53
Methods of Passive Transport
12:07
Passive and Active Transport
12:08
Simple Diffusion
12:45
Facilitated Diffusion
15:20
Osmosis
17:17
Definition and Example of Osmosis
17:18
Hypertonic, Hypotonic, and Isotonic
21:47
Active Transport
27:57
Active Transport
28:17
Sodium and Potassium Pump
29:45
Cotransport
34:38
2 Types of Active Transport
37:09
Endocytosis and Exocytosis
37:38
Endocytosis and Exocytosis
37:51
Types of Endocytosis: Pinocytosis
40:39
Types of Endocytosis: Phagocytosis
41:02
Receptor Mediated Endocytosis
41:27
Receptor Mediated Endocytosis
41:28
Example 1: Cell Membrane and Permeable Substances
43:59
Example 2: Osmosis
45:20
Example 3: Active Transport, Cotransport, Simple and Facilitated Diffusion
47:36
Example 4: Match Terms with Definition
50:55
Cellular Communication

57m 9s

Intro
0:00
Extracellular Matrix
0:28
The Extracellular Matrix (ECM)
0:29
ECM in Animal Cells
0:55
Fibronectin and Integrins
1:34
Intercellular Communication in Plants
2:48
Intercellular Communication in Plants: Plasmodesmata
2:50
Cell to Cell Communication in Animal Cells
3:39
Cell Junctions
3:42
Desmosomes
3:54
Tight Junctions
5:07
Gap Junctions
7:00
Cell Signaling
8:17
Cell Signaling: Ligand and Signal Transduction Pathway
8:18
Direct Contact
8:48
Over Distances Contact and Hormones
10:09
Stages of Cell Signaling
11:53
Reception Phase
11:54
Transduction Phase
13:49
Response Phase
14:45
Cell Membrane Receptors
15:37
G-Protein Coupled Receptor
15:38
Cell Membrane Receptor, Cont.
21:37
Receptor Tyrosine Kinases (RTKs)
21:38
Autophosphorylation, Monomer, and Dimer
22:57
Cell Membrane Receptor, Cont.
27:01
Ligand-Gated Ion Channels
27:02
Intracellular Receptors
29:43
Intracellular Receptor and Receptor -Ligand Complex
29:44
Signal Transduction
32:57
Signal Transduction Pathways
32:58
Adenylyl Cyclase and cAMP
35:53
Second Messengers
39:18
cGMP, Inositol Trisphosphate, and Diacylglycerol
39:20
Cell Response
45:15
Cell Response
45:16
Apoptosis
46:57
Example 1: Tight Junction and Gap Junction
48:29
Example 2: Three Phases of Cell Signaling
51:48
Example 3: Ligands and Binding of Hormone
54:03
Example 4: Signal Transduction
56:06
III. Cell Division
The Cell Cycle

37m 49s

Intro
0:00
Functions of Cell Division
0:09
Overview of Cell Division: Reproduction, Growth, and Repair
0:11
Important Term: Daughter Cells
2:25
Chromosome Structure
3:36
Chromosome Structure: Sister Chromatids and Centromere
3:37
Chromosome Structure: Chromatin
4:31
Chromosome with One Chromatid or Two Chromatids
5:25
Chromosome Structure: Long and Short Arm
6:49
Mitosis and Meiosis
7:00
Mitosis
7:41
Meiosis
8:40
The Cell Cycle
10:43
Mitotic Phase and Interphase
10:44
Cytokinesis
15:51
Cytokinesis in Animal Cell: Cleavage Furrow
15:52
Cytokinesis in Plant Cell: Cell Plate
17:28
Control of the Cell Cycle
18:28
Cell Cycle Control System and Checkpoints
18:29
Cyclins and Cyclin Dependent Kinases
21:18
Cyclins and Cyclin Dependent Kinases (CDKSs)
21:20
MPF
23:17
Internal Factor Regulating Cell Cycle
24:00
External Factor Regulating Cell Cycle
24:53
Contact Inhibition and Anchorage Dependent
25:53
Cancer and the Cell Cycle
27:42
Cancer Cells
27:46
Example1: Parts of the Chromosome
30:15
Example 2: Cell Cycle
31:50
Example 3: Control of the Cell Cycle
33:32
Example 4: Cancer and the Cell
35:01
Mitosis

35m 1s

Intro
0:00
Review of the Cell Cycle
0:09
Interphase: G1 Phase
0:34
Interphase: S Phase
0:56
Interphase: G2 Phase
1:31
M Phase: Mitosis and Cytokinesis
1:47
Overview of Mitosis
3:08
What is Mitosis?
3:10
Overview of Mitosis
3:17
Diploid and Haploid
5:37
Homologous Chromosomes
6:04
The Spindle Apparatus
11:57
The Spindle Apparatus
12:00
Centrosomes and Centrioles
12:40
Microtubule Organizing Center
13:03
Spindle Fiber of Spindle Microtubules
13:23
Kinetochores
14:06
Asters
15:45
Prophase
16:47
First Phase of Mitosis: Prophase
16:54
Metaphase
20:05
Second Phase of Mitosis: Metaphase
20:10
Anaphase
22:52
Third Phase of Mitosis: Anaphase
22:53
Telophase and Cytokinesis
24:34
Last Phase of Mitosis: Telophase and Cytokinesis
24:35
Summary of Mitosis
27:46
Summary of Mitosis
27:47
Example 1: Spindle Apparatus
28:50
Example 2: Last Phase of Mitosis
30:39
Example 3: Prophase
32:41
Example 4: Identify the Phase
33:52
Meiosis

1h 58s

Intro
0:00
Haploid and Diploid Cells
0:09
Diploid and Somatic Cells
0:29
Haploid and Gametes
1:20
Example: Human Cells and Chromosomes
1:41
Sex Chromosomes
6:00
Comparison of Mitosis and Meiosis
10:42
Mitosis Vs. Meiosis: Cell Division
10:59
Mitosis Vs. Meiosis: Daughter Cells
12:31
Meiosis: Pairing of Homologous Chromosomes
13:40
Mitosis and Meiosis
14:21
Process of Mitosis
14:27
Process of Meiosis
16:12
Synapsis and Crossing Over
19:14
Prophase I: Synapsis and Crossing Over
19:15
Chiasmata
22:33
Meiosis I
25:49
Prophase I: Crossing Over
25:50
Metaphase I: Homologs Line Up
26:00
Anaphase I: Homologs Separate
28:16
Telophase I and Cytokinesis
29:15
Independent Assortment
30:58
Meiosis II
32:17
Propphase II
33:50
Metaphase II
34:06
Anaphase II
34:50
Telophase II
36:09
Cytokinesis
37:00
Summary of Meiosis
38:15
Summary of Meiosis
38:16
Cell Division Mechanism in Plants
41:57
Example 1: Cell Division and Meiosis
46:15
Example 2: Phases of Meiosis
50:22
Example 3: Label the Figure
54:29
Example 4: Four Differences Between Mitosis and Meiosis
56:37
IV. Cellular Energetics
Enzymes

51m 3s

Intro
0:00
Law of Thermodynamics
0:08
Thermodynamics
0:09
The First Law of Thermodynamics
0:37
The Second Law of Thermodynamics
1:24
Entropy
1:35
The Gibbs Free Energy Equation
3:07
The Gibbs Free Energy Equation
3:08
ATP
8:23
Adenosine Triphosphate (ATP)
8:24
Cellular Respiration
11:32
Catabolic Pathways
12:28
Anabolic Pathways
12:54
Enzymes
14:31
Enzymes
14:32
Enzymes and Exergonic Reaction
14:40
Enzymes and Endergonic Reaction
16:36
Enzyme Specificity
21:29
Substrate
21:41
Induced Fit
23:04
Factors Affecting Enzyme Activity
25:55
Substrate Concentration
26:07
pH
27:10
Temperature
29:14
Presence of Cofactors
29:57
Regulation of Enzyme Activity
31:12
Competitive Inhibitors
32:13
Noncompetitive Inhibitors
33:52
Feedback Inhibition
35:22
Allosteric Interactions
36:56
Allosteric Regulators
37:00
Example 1: Is the Inhibitor Competitive or Noncompetitive?
40:49
Example 2: Thermophiles
44:18
Example 3: Exergonic or Endergonic
46:09
Example 4: Energy Vs. Reaction Progress Graph
48:47
Glycolysis and Anaerobic Respiration

38m 1s

Intro
0:00
Cellular Respiration Overview
0:13
Cellular Respiration
0:14
Anaerobic Respiration vs. Aerobic Respiration
3:50
Glycolysis Overview
4:48
Overview of Glycolysis
4:50
Glycolysis Involves a Redox Reaction
7:02
Redox Reaction
7:04
Glycolysis
15:04
Important Facts About Glycolysis
15:07
Energy Invested Phase
16:12
Splitting of Fructose 1,6-Phosphate and Energy Payoff Phase
17:50
Substrate Level Phophorylation
22:12
Aerobic Versus Anaerobic Respiration
23:57
Aerobic Versus Anaerobic Respiration
23:58
Cellular Respiration Overview
27:15
When Cellular Respiration is Anaerobic
27:17
Glycolysis
28:26
Alcohol Fermentation
28:45
Lactic Acid Fermentation
29:58
Example 1: Glycolysis
31:04
Example 2: Glycolysis, Fermentation and Anaerobic Respiration
33:44
Example 3: Aerobic Respiration Vs. Anaerobic Respiration
35:25
Example 4: Exergonic Reaction and Endergonic Reaction
36:42
Aerobic Respiration

51m 6s

Intro
0:00
Aerobic Vs. Anaerobic Respiration
0:06
Aerobic and Anaerobic Comparison
0:07
Review of Glycolysis
1:48
Overview of Glycolysis
2:06
Glycolysis: Energy Investment Phase
2:25
Glycolysis: Energy Payoff Phase
2:58
Conversion of Pyruvate to Acetyl CoA
4:55
Conversion of Pyruvate to Acetyl CoA
4:56
Energy Formation
8:06
Mitochondrial Structure
8:58
Endosymbiosis Theory
9:23
Matrix
10:00
Outer Membrane, Inner Membrane, and Intermembrane Space
10:43
Cristae
11:47
The Citric Acid Cycle
12:11
The Citric Acid Cycle (Also Called Krebs Cycle)
12:12
Substrate Level Phosphorylation
18:47
Summary of ATP, NADH, and FADH2 Production
23:13
Process: Glycolysis
23:28
Process: Acetyl CoA Production
23:36
Process: Citric Acid Cycle
23:52
The Electron Transport Chain
24:24
Oxidative Phosphorylation
24:28
The Electron Transport Chain and ATP Synthase
25:20
Carrier Molecules: Cytochromes
27:18
Carrier Molecules: Flavin Mononucleotide (FMN)
28:05
Chemiosmosis
32:46
The Process of Chemiosmosis
32:47
Summary of ATP Produced by Aerobic Respiration
38:24
ATP Produced by Aerobic Respiration
38:27
Example 1: Aerobic Respiration
43:38
Example 2: Label the Location for Each Process and Structure
45:08
Example 3: The Electron Transport Chain
47:06
Example 4: Mitochondrial Inner Membrane
48:38
Photosynthesis

1h 2m 52s

Intro
0:00
Photosynthesis
0:09
Introduction to Photosynthesis
0:10
Autotrophs and Heterotrophs
0:25
Overview of Photosynthesis Reaction
1:05
Leaf Anatomy and Chloroplast Structure
2:54
Chloroplast
2:55
Cuticle
3:16
Upper Epidermis
3:27
Mesophyll
3:40
Stomates
4:00
Guard Cells
4:45
Transpiration
5:01
Vascular Bundle
5:20
Stroma and Double Membrane
6:20
Grana
7:17
Thylakoids
7:30
Dark Reaction and Light Reaction
7:46
Light Reactions
8:43
Light Reactions
8:47
Pigments: Chlorophyll a, Chlorophyll b, and Carotenoids
9:19
Wave and Particle
12:10
Photon
12:34
Photosystems
13:24
Photosystems
13:28
Reaction-Center Complex and Light Harvesting Complexes
14:01
Noncyclic Photophosphorylation
17:46
Noncyclic Photophosphorylation Overview
17:47
What is Photophosphorylation?
18:25
Noncyclic Photophosphorylation Process
19:07
Photolysis and The Rest of Noncyclic Photophosphorylation
21:33
Cyclic Photophosphorylation
31:45
Cyclic Photophosphorylation
31:46
Light Independent Reactions
34:34
The Calvin Cycle
34:35
C3 Plants and Photorespiration
40:31
C3 Plants and Photorespiration
40:32
C4 Plants
45:32
C4 Plants: Structures and Functions
45:33
CAM Plants
50:25
CAM Plants: Structures and Functions
50:35
Example 1: Calvin Cycle
54:34
Example 2: C4 Plant
55:48
Example 3: Photosynthesis and Photorespiration
58:35
Example 4: CAM Plants
1:00:41
V. Molecular Genetics
DNA Synthesis

38m 45s

Intro
0:00
Review of DNA Structure
0:09
DNA Molecules
0:10
Nitrogenous Base: Pyrimidines and Purines
1:25
DNA Double Helix
3:03
Complementary Strands of DNA
3:12
5' to 3' & Antiparallel
4:55
Overview of DNA Replication
7:10
DNA Replication & Semiconservative
7:11
DNA Replication
10:26
Origin of Replication
10:28
Helicase
11:10
Single-Strand Binding Protein
12:05
Topoisomerases
13:14
DNA Polymerase
14:26
Primase
15:55
Leading and Lagging Strands
16:51
Leading Strand and Lagging Strand
16:52
Okazaki Fragments
18:10
DNA Polymerase I
20:11
Ligase
21:12
Proofreading and Mismatch Repair
22:18
Proofreading
22:19
Mismatch
23:33
Telomeres
24:58
Telomeres
24:59
Example 1: Function of Enzymes During DNA Synthesis
28:09
Example 2: Accuracy of the DNA Sequence
31:42
Example 3: Leading Strand and Lagging Strand
32:38
Example 4: Telomeres
35:40
Transcription and Translation

1h 17m 1s

Intro
0:00
Transcription and Translation Overview
0:07
From DNA to RNA to Protein
0:09
Structure and Types of RNA
3:14
Structure and Types of RNA
3:33
mRNA
6:19
rRNA
7:02
tRNA
7:28
Transcription
7:54
Initiation Phase
8:11
Elongation Phase
12:12
Termination Phase
14:51
RNA Processing
16:11
Types of RNA Processing
16:12
Exons and Introns
16:35
Splicing & Spliceosomes
18:27
Addition of a 5' Cap and a Poly A tail
20:41
Alternative Splicing
21:43
Translation
23:41
Nucleotide Triplets or Codons
23:42
Start Codon
25:24
Stop Codons
25:38
Coding of Amino Acids and Wobble Position
25:57
Translation Cont.
28:29
Transfer RNA (tRNA): Structures and Functions
28:30
Ribosomes
35:15
Peptidyl, Aminoacyl, and Exit Site
35:23
Steps of Translation
36:58
Initiation Phase
37:12
Elongation Phase
43:12
Termination Phase
45:28
Mutations
49:43
Types of Mutations
49:44
Substitutions: Silent
51:11
Substitutions: Missense
55:27
Substitutions: Nonsense
59:37
Insertions and Deletions
1:01:10
Example 1: Three Types of Processing that are Performed on pre-mRNA
1:06:53
Example 2: The Process of Translation
1:09:10
Example 3: Transcription
1:12:04
Example 4: Three Types of Substitution Mutations
1:14:09
Viral Structure and Genetics

43m 12s

Intro
0:00
Structure of Viruses
0:09
Structure of Viruses: Capsid and Envelope
0:10
Bacteriophage
1:48
Other Viruses
2:28
Overview of Viral Reproduction
3:15
Host Range
3:48
Step 1: Bind to Host Cell
4:39
Step 2: Viral Nuclei Acids Enter the Cell
5:15
Step 3: Viral Nucleic Acids & Proteins are Synthesized
5:54
Step 4: Virus Assembles
6:34
Step 5: Virus Exits the Cell
6:55
The Lytic Cycle
7:37
Steps in the Lytic Cycle
7:38
The Lysogenic Cycle
11:27
Temperate Phage
11:34
Steps in the Lysogenic Cycle
12:09
RNA Viruses
16:57
Types of RNA Viruses
17:15
Positive Sense
18:16
Negative Sense
18:48
Reproductive Cycle of RNA Viruses
19:32
Retroviruses
25:48
Complementary DNA (cDNA) & Reverse Transcriptase
25:49
Life Cycle of a Retrovirus
28:22
Prions
32:42
Prions: Definition and Examples
32:45
Viroids
34:46
Example 1: The Lytic Cycle
35:37
Example 2: Retrovirus
38:03
Example 3: Positive Sense RNA vs. Negative Sense RNA
39:10
Example 4: The Lysogenic Cycle
40:42
Bacterial Genetics and Gene Regulation

49m 45s

Intro
0:00
Bacterial Genomes
0:09
Structure of Bacterial Genomes
0:16
Transformation
1:22
Transformation
1:23
Vector
2:49
Transduction
3:32
Process of Transduction
3:38
Conjugation
8:06
Conjugation & F factor
8:07
Operons
14:02
Definition and Example of Operon
14:52
Structural Genes
16:23
Promoter Region
17:04
Regulatory Protein & Operators
17:53
The lac Operon
20:09
The lac Operon: Inducible System
20:10
The trp Operon
28:02
The trp Operon: Repressible System
28:03
Corepressor
31:37
Anabolic & Catabolic
33:12
Positive Regulation of the lac Operon
34:39
Positive Regulation of the lac Operon
34:40
Example 1: The Process of Transformation
39:07
Example 2: Operon & Terms
43:29
Example 3: Inducible lac Operon and Repressible trp Operon
45:15
Example 4: lac Operon
47:10
Eukaryotic Gene Regulation and Mobile Genetic Elements

54m 26s

Intro
0:00
Mechanism of Gene Regulation
0:11
Differential Gene Expression
0:13
Levels of Regulation
2:24
Chromatin Structure and Modification
4:35
Chromatin Structure
4:36
Levels of Packing
5:50
Euchromatin and Heterochromatin
8:58
Modification of Chromatin Structure
9:58
Epigenetic
12:49
Regulation of Transcription
14:20
Promoter Region, Exon, and Intron
14:26
Enhancers: Control Element
15:31
Enhancer & DNA-Bending Protein
17:25
Coordinate Control
21:23
Silencers
23:01
Post-Transcriptional Regulation
24:05
Post-Transcriptional Regulation
24:07
Alternative Splicing
27:19
Differences in mRNA Stability
28:02
Non-Coding RNA Molecules: micro RNA & siRNA
30:01
Regulation of Translation and Post-Translational Modifications
32:31
Regulation of Translation and Post-Translational Modifications
32:55
Ubiquitin
35:21
Proteosomes
36:04
Transposons
37:50
Mobile Genetic Elements
37:56
Barbara McClintock
38:37
Transposons & Retrotransposons
40:38
Insertion Sequences
43:14
Complex Transposons
43:58
Example 1: Four Mechanisms that Decrease Production of Protein
45:13
Example 2: Enhancers and Gene Expression
49:09
Example 3: Primary Transcript
50:41
Example 4: Retroviruses and Retrotransposons
52:11
Biotechnology

49m 26s

Intro
0:00
Definition of Biotechnology
0:08
Biotechnology
0:09
Genetic Engineering
1:05
Example: Golden Corn
1:57
Recombinant DNA
2:41
Recombinant DNA
2:42
Transformation
3:24
Transduction
4:24
Restriction Enzymes, Restriction Sites, & DNA Ligase
5:32
Gene Cloning
13:48
Plasmids
14:20
Gene Cloning: Step 1
17:35
Gene Cloning: Step 2
17:57
Gene Cloning: Step 3
18:53
Gene Cloning: Step 4
19:46
Gel Electrophoresis
27:25
What is Gel Electrophoresis?
27:26
Gel Electrophoresis: Step 1
28:13
Gel Electrophoresis: Step 2
28:24
Gel Electrophoresis: Step 3 & 4
28:39
Gel Electrophoresis: Step 5
29:55
Southern Blotting
31:25
Polymerase Chain Reaction (PCR)
32:11
Polymerase Chain Reaction (PCR)
32:12
Denaturing Phase
35:40
Annealing Phase
36:07
Elongation/ Extension Phase
37:06
DNA Sequencing and the Human Genome Project
39:19
DNA Sequencing and the Human Genome Project
39:20
Example 1: Gene Cloning
40:40
Example 2: Recombinant DNA
43:04
Example 3: Match Terms With Descriptions
45:43
Example 4: Polymerase Chain Reaction
47:36
VI. Heredity
Mendelian Genetics

1h 32m 8s

Intro
0:00
Background
0:40
Gregory Mendel & Mendel's Law
0:41
Blending Hypothesis
1:04
Particulate Inheritance
2:08
Terminology
2:55
Gene
3:05
Locus
3:57
Allele
4:37
Dominant Allele
5:48
Recessive Allele
7:38
Genotype
9:22
Phenotype
10:01
Homozygous
10:44
Heterozygous
11:39
Penetrance
11:57
Expressivity
14:15
Mendel's Experiments
15:31
Mendel's Experiments: Pea Plants
15:32
The Law of Segregation
21:16
Mendel's Conclusions
21:17
The Law of Segregation
22:57
Punnett Squares
28:27
Using Punnet Squares
28:30
The Law of Independent Assortment
32:35
Monohybrid
32:38
Dihybrid
33:29
The Law of Independent Assortment
34:00
The Law of Independent Assortment, cont.
38:13
The Law of Independent Assortment: Punnet Squares
38:29
Meiosis and Mendel's Laws
43:38
Meiosis and Mendel's Laws
43:39
Test Crosses
49:07
Test Crosses Example
49:08
Probability: Multiplication Rule and the Addition Rule
53:39
Probability Overview
53:40
Independent Events & Multiplication Rule
55:40
Mutually Exclusive Events & Addition Rule
1:00:25
Incomplete Dominance, Codominance and Multiple Alleles
1:02:55
Incomplete Dominance
1:02:56
Incomplete Dominance, Codominance and Multiple Alleles
1:07:06
Codominance and Multiple Alleles
1:07:08
Polygenic Inheritance and Pleoitropy
1:10:19
Polygenic Inheritance and Pleoitropy
1:10:26
Epistasis
1:12:51
Example of Epistasis
1:12:52
Example 1: Genetic of Eye Color and Height
1:17:39
Example 2: Blood Type
1:21:57
Example 3: Pea Plants
1:25:09
Example 4: Coat Color
1:28:34
Linked Genes and Non-Mendelian Modes of Inheritance

39m 38s

Intro
0:00
Review of the Law of Independent Assortment
0:14
Review of the Law of Independent Assortment
0:24
Linked Genes
6:06
Linked Genes
6:07
Bateson & Pannett: Pea Plants
8:00
Crossing Over and Recombination
15:17
Crossing Over and Recombination
15:18
Extranuclear Genes
20:50
Extranuclear Genes
20:51
Cytoplasmic Genes
21:31
Genomic Imprinting
23:45
Genomic Imprinting
23:58
Methylation
24:43
Example 1: Recombination Frequencies & Linkage Map
27:07
Example 2: Linked Genes
28:39
Example 3: Match Terms to Correct Descriptions
36:46
Example 4: Leber's Optic Neuropathy
38:40
Sex-Linked Traits and Pedigree Analysis

43m 39s

Intro
0:00
Sex-Linked Traits
0:09
Human Chromosomes, XY, and XX
0:10
Thomas Morgan's Drosophila
1:44
X-Inactivation and Barr Bodies
14:48
X-Inactivation Overview
14:49
Calico Cats Example
17:04
Pedigrees
19:24
Definition and Example of Pedigree
19:25
Autosomal Dominant Inheritance
20:51
Example: Huntington's Disease
20:52
Autosomal Recessive Inheritance
23:04
Example: Cystic Fibrosis, Tay-Sachs Disease, and Phenylketonuria
23:05
X-Linked Recessive Inheritance
27:06
Example: Hemophilia, Duchene Muscular Dystrohpy, and Color Blindess
27:07
Example 1: Colorblind
29:48
Example 2: Pedigree
37:07
Example 3: Inheritance Pattern
39:54
Example 4: X-inactivation
41:17
VII. Evolution
Natural Selection

1h 3m 28s

Intro
0:00
Background
0:09
Work of Other Scientists
0:15
Aristotle
0:43
Carl Linnaeus
1:32
George Cuvier
2:47
James Hutton
4:10
Thomas Malthus
5:05
Jean-Baptiste Lamark
5:45
Darwin's Theory of Natural Selection
7:50
Evolution
8:00
Natural Selection
8:43
Charles Darwin & The Galapagos Islands
10:20
Genetic Variation
20:37
Mutations
20:38
Independent Assortment
21:04
Crossing Over
24:40
Random Fertilization
25:26
Natural Selection and the Peppered Moth
26:37
Natural Selection and the Peppered Moth
26:38
Types of Natural Selection
29:52
Directional Selection
29:55
Stabilizing Selection
32:43
Disruptive Selection
34:21
Sexual Selection
36:18
Sexual Dimorphism
37:30
Intersexual Selection
37:57
Intrasexual Selection
39:20
Evidence for Evolution
40:55
Paleontology: Fossil Record
41:30
Biogeography
45:35
Continental Drift
46:06
Pangaea
46:28
Marsupials
47:11
Homologous and Analogous Structure
50:10
Homologous Structure
50:12
Analogous Structure
53:21
Example 1: Genetic Variation & Natural Selection
56:15
Example 2: Types of Natural Selection
58:07
Example 3: Mechanisms By Which Genetic Variation is Maintained Within a Population
1:00:12
Example 4: Difference Between Homologous and Analogous Structures
1:01:28
Population Genetic and Evolution

53m 22s

Intro
0:00
Review of Natural Selection
0:12
Review of Natural Selection
0:13
Genetic Drift and Gene Flow
4:40
Definition of Genetic Drift
4:41
Example of Genetic Drift: Cholera Epidemic
5:15
Genetic Drift: Founder Effect
7:28
Genetic Drift: Bottleneck Effect
10:27
Gene Flow
13:00
Quantifying Genetic Variation
14:32
Average Heterozygosity
15:08
Nucleotide Variation
17:05
Maintaining Genetic Variation
18:12
Heterozygote Advantage
19:45
Example of Heterozygote Advantage: Sickle Cell Anemia
20:21
Diploidy
23:44
Geographic Variation
26:54
Frequency Dependent Selection and Outbreeding
28:15
Neutral Traits
30:55
The Hardy-Weinberg Equilibrium
31:11
The Hardy-Weinberg Equilibrium
31:49
The Hardy-Weinberg Conditions
32:42
The Hardy-Weinberg Equation
34:05
The Hardy-Weinberg Example
36:33
Example 1: Match Terms to Descriptions
42:28
Example 2: The Hardy-Weinberg Equilibrium
44:31
Example 3: The Hardy-Weinberg Equilibrium
49:10
Example 4: Maintaining Genetic Variation
51:30
Speciation and Patterns of Evolution

51m 2s

Intro
0:00
Early Life on Earth
0:08
Early Earth
0:09
1920's Oparin & Haldane
0:58
Abiogenesis
2:15
1950's Miller & Urey
2:45
Ribozymes
5:34
3.5 Billion Years Ago
6:39
2.5 Billion Years Ago
7:14
1.5 Billion Years Ago
7:41
Endosymbiosis
8:00
540 Million Years Ago: Cambrian Explosion
9:57
Gradualism and Punctuated Equilibrium
11:46
Gradualism
11:47
Punctuated Equilibrium
12:45
Adaptive Radiation
15:08
Adaptive Radiation
15:09
Example of Adaptive Radiation: Galapogos Islands
17:11
Convergent Evolution, Divergent Evolution, and Coevolution
18:30
Convergent Evolution
18:39
Divergent Evolution
21:30
Coevolution
23:49
Speciation
26:27
Definition and Example of Species
26:29
Reproductive Isolation: Prezygotive
27:49
Reproductive Isolation: Post zygotic
29:28
Allopatric Speciation
30:21
Allopatric Speciation & Geographic Isolation
30:28
Genetic Drift
31:31
Sympatric Speciation
34:10
Sympatric Speciation
34:11
Polyploidy & Autopolyploidy
35:12
Habitat Isolation
39:17
Temporal Isolation
41:27
Selection Selection
41:40
Example 1: Pattern of Evolution
42:53
Example 2: Sympatric Speciation
45:16
Example 3: Patterns of Evolution
48:08
Example 4: Patterns of Evolution
49:27
VIII. Diversity of Life
Classification

1h 51s

Intro
0:00
Systems of Classification
0:07
Taxonomy
0:08
Phylogeny
1:04
Phylogenetics Tree
1:44
Cladistics
3:37
Classification of Organisms
5:31
Example of Carl Linnaeus System
5:32
Domains
9:26
Kingdoms: Monera, Protista, Plantae, Fungi, Animalia
9:27
Monera
10:06
Phylogentics Tree: Eurkarya, Bacteria, Archaea
11:58
Domain Eukarya
12:50
Domain Bacteria
15:43
Domain Bacteria
15:46
Pathogens
16:41
Decomposers
18:00
Domain Archaea
19:43
Extremophiles Archaea: Thermophiles and Halophiles
19:44
Methanogens
20:58
Phototrophs, Autotrophs, Chemotrophs and Heterotrophs
24:40
Phototrophs and Chemotrophs
25:02
Autotrophs and Heterotrophs
26:54
Photoautotrophs
28:50
Photoheterotrophs
29:28
Chemoautotrophs
30:06
Chemoheterotrophs
31:37
Domain Eukarya
32:40
Domain Eukarya
32:43
Plant Kingdom
34:28
Protists
35:48
Fungi Kingdom
37:06
Animal Kingdom
38:35
Body Symmetry
39:25
Lack Symetry
39:40
Radial Symmetry: Sea Aneome
40:15
Bilateral Symmetry
41:55
Cephalization
43:29
Germ Layers
44:54
Diploblastic Animals
45:18
Triploblastic Animals
45:25
Ectoderm
45:36
Endoderm
46:07
Mesoderm
46:41
Coelomates
47:14
Coelom
47:15
Acoelomate
48:22
Pseudocoelomate
48:59
Coelomate
49:31
Protosomes
50:46
Deuterosomes
51:20
Example 1: Domains
53:01
Example 2: Match Terms with Descriptions
56:00
Example 3: Kingdom Monera and Domain Archaea
57:50
Example 4: System of Classification
59:37
Bacteria

36m 46s

Intro
0:00
Comparison of Domain Archaea and Domain Bacteria
0:08
Overview of Archaea and Bacteria
0:09
Archaea vs. Bacteria: Nucleus, Organelles, and Organization of Genetic Material
1:45
Archaea vs. Bacteria: Cell Walls
2:20
Archaea vs. Bacteria: Number of Types of RNA Pol
2:29
Archaea vs. Bacteria: Membrane Lipids
2:53
Archaea vs. Bacteria: Introns
3:33
Bacteria: Pathogen
4:03
Bacteria: Decomposers and Fix Nitrogen
5:18
Bacteria: Aerobic, Anaerobic, Strict Anaerobes & Facultative Anaerobes
6:02
Phototrophs, Autotrophs, Heterotrophs and Chemotrophs
7:14
Phototrophs and Chemotrophs
7:50
Autotrophs and Heterotrophs
8:53
Photoautotrophs and Photoheterotrophs
10:15
Chemoautotroph and Chemoheterotrophs
11:07
Structure of Bacteria
12:21
Shapes: Cocci, Bacilli, Vibrio, and Spirochetes
12:26
Structures: Plasma Membrane and Cell Wall
14:23
Structures: Nucleoid Region, Plasmid, and Capsule Basal Apparatus, and Filament
15:30
Structures: Flagella, Basal Apparatus, Hook, and Filament
16:36
Structures: Pili, Fimbrae and Ribosome
18:00
Peptidoglycan: Gram + and Gram -
18:50
Bacterial Genomes and Reproduction
21:14
Bacterial Genomes
21:21
Reproduction of Bacteria
22:13
Transformation
23:26
Vector
24:34
Competent
25:15
Conjugation
25:53
Conjugation: F+ and R Plasmids
25:55
Example 1: Species
29:41
Example 2: Bacteria and Exchange of Genetic Material
32:31
Example 3: Ways in Which Bacteria are Beneficial to Other Organisms
33:48
Example 4: Domain Bacteria vs. Domain Archaea
34:53
Protists

1h 18m 48s

Intro
0:00
Classification of Protists
0:08
Classification of Protists
0:09
'Plant-like' Protists
2:06
'Animal-like' Protists
3:19
'Fungus-like' Protists
3:57
Serial Endosymbiosis Theory
5:15
Endosymbiosis Theory
5:33
Photosynthetic Protists
7:33
Life Cycles with a Diploid Adult
13:35
Life Cycles with a Diploid Adult
13:56
Life Cycles with a Haploid Adult
15:31
Life Cycles with a Haploid Adult
15:32
Alternation of Generations
17:22
Alternation of Generations: Multicellular Haploid & Diploid Phase
17:23
Plant-Like Protists
19:58
Euglenids
20:43
Dino Flagellates
22:57
Diatoms
26:07
Plant-Like Protists
28:44
Golden Algae
28:45
Brown Algeas
30:05
Plant-Like Protists
33:38
Red Algae
33:39
Green Algae
35:36
Green Algae: Chlamydomonus
37:44
Animal-Like Protists
40:04
Animal-Like Protists Overview
40:05
Sporozoans (Apicomplexans)
40:32
Alveolates
41:41
Sporozoans (Apicomplexans): Plasmodium & Malaria
42:59
Animal-Like Protists
48:44
Kinetoplastids
48:50
Example of Kinetoplastids: Trypanosomes & African Sleeping Sickness
49:30
Ciliate
50:42
Conjugation
53:16
Conjugation
53:26
Animal-Like Protists
57:08
Parabasilids
57:31
Diplomonads
59:06
Rhizopods
1:00:13
Forams
1:02:25
Radiolarians
1:03:28
Fungus-Like Protists
1:04:25
Fungus-Like Protists Overview
1:04:26
Slime Molds
1:05:15
Cellular Slime Molds: Feeding Stage
1:09:21
Oomycetes
1:11:15
Example 1: Alternation of Generations and Sexual Life Cycles
1:13:05
Example 2: Match Protists to Their Descriptions
1:14:12
Example 3: Three Structures that Protists Use for Motility
1:16:22
Example 4: Paramecium
1:17:04
Fungi

35m 24s

Intro
0:00
Introduction to Fungi
0:09
Introduction to Fungi
0:10
Mycologist
0:34
Examples of Fungi
0:45
Hyphae, Mycelia, Chitin, and Coencytic Fungi
2:26
Ancestral Protists
5:00
Role of Fungi in the Environment
5:35
Fungi as Decomposers
5:36
Mycorrrhiza
6:19
Lichen
8:52
Life Cycle of Fungi
11:32
Asexual Reproduction
11:33
Sexual Reproduction & Dikaryotic Cell
13:16
Chytridiomycota
18:12
Phylum Chytridiomycota
18:17
Zoospores
18:50
Zygomycota
19:07
Coenocytic & Zygomycota Life Cycle
19:08
Basidiomycota
24:27
Basidiomycota Overview
24:28
Basidiomycota Life Cycle
26:11
Ascomycota
28:00
Ascomycota Overview
28:01
Ascomycota Reproduction
28:50
Example 1: Fungi Fill in the Blank
31:02
Example 2: Name Two Roles Played by Fungi in the Environment
32:09
Example 3: Difference Between Diploid Cell and Dikaryon Cell
33:42
Example 4: Phylum of Fungi, Flagellated Spore, Coencytic
34:36
Invertebrates

1h 3m 3s

Intro
0:00
Porifera (Sponges)
0:33
Chordata
0:56
Porifera (Sponges): Sessile, Layers, Aceolomates, and Filter Feeders
1:24
Amoebocytes Cell
4:47
Choanocytes Cell
5:56
Sexual Reproduction
6:28
Cnidaria
8:05
Cnidaria Overview
8:06
Polyp & Medusa: Gastrovasular Cavity
8:29
Cnidocytes
9:42
Anthozoa
10:40
Cubozoa
11:23
Hydrozoa
11:53
Scyphoza
13:25
Platyhelminthes (Flatworms)
13:58
Flatworms: Tribloblastic, Bilateral Symmetry, and Cephalization
13:59
GI System
15:33
Excretory System
16:07
Nervous System
17:00
Turbellarians
17:36
Trematodes
18:42
Monageneans
21:32
Cestoda
21:55
Rotifera (Rotifers)
23:45
Rotifers: Digestive Tract, Pseudocoelem, and Stuctures
23:46
Reproduction: Parthenogenesis
25:33
Nematoda (Roundworms)
26:44
Nematoda (Roundworms)
26:45
Parasites: Pinworms & Hookworms
27:26
Annelida
28:36
Annelida Overview
28:37
Open Circulatory
29:21
Closed Circulatory
30:18
Nervous System
31:19
Excretory System
31:43
Oligochaete
32:07
Leeches
33:22
Polychaetes
34:42
Mollusca
35:26
Mollusca Features
35:27
Major Part 1: Visceral Mass
36:21
Major Part 2: Head-foot Region
36:49
Major Part 3: Mantle
37:13
Radula
37:49
Circulatory, Reproductive, Excretory, and Nervous System
38:14
Major Classes of Molluscs
39:12
Gastropoda
39:17
Polyplacophora
40:15
Bivales
40:41
Cephalopods
41:42
Arthropoda
43:35
Arthropoda Overview
43:36
Segmented Bodies
44:14
Exoskeleton
44:52
Jointed Appendages
45:28
Hemolyph, Excretory & Respiratory System
45:41
Myriapoda & Centipedes
47:15
Cheliceriforms
48:20
Crustcea
49:31
Herapoda
50:03
Echinodermata
52:59
Echinodermata
53:00
Watrer Vascular System
54:20
Selected Characteristics of Invertebrates
57:11
Selected Characteristics of Invertebrates
57:12
Example 1: Phylum Description
58:43
Example 2: Complex Animals
59:50
Example 3: Match Organisms to the Correct Phylum
1:01:03
Example 4: Phylum Arthropoda
1:02:01
Vertebrates

1h 7s

Intro
0:00
Phylum Chordata
0:06
Chordates Overview
0:07
Notochord and Dorsal Hollow Nerve Chord
1:24
Pharyngeal Clefts, Arches, and Post-anal Tail
3:41
Invertebrate Chordates
6:48
Lancelets
7:13
Tunicates
8:02
Hagfishes: Craniates
8:55
Vertebrate Chordates
10:41
Veterbrates Overview
10:42
Lampreys
11:00
Gnathostomes
12:20
Six Major Classes of Vertebrates
12:53
chondrichthyes
14:23
Chondrichthyes Overview
14:24
Ectothermic and Endothermic
14:42
Sharks: Lateral Line System, Neuromastsn, and Gills
15:27
Oviparous and Viviparous
17:23
Osteichthyes (Bony Fishes)
18:12
Osteichythes (Bony Fishes) Overview
18:13
Operculum
19:05
Swim Bladder
19:53
Ray-Finned Fishes
20:34
Lobe-Finned Fishes
20:58
Tetrapods
22:36
Tetrapods: Definition and Examples
22:37
Amphibians
23:53
Amphibians Overview
23:54
Order Urodela
25:51
Order Apoda
27:03
Order Anura
27:55
Reptiles
30:19
Reptiles Overview
30:20
Amniotes
30:37
Examples of Reptiles
32:46
Reptiles: Ectotherms, Gas Exchange, and Heart
33:40
Orders of Reptiles
34:17
Sphenodontia, Squamata, Testudines, and Crocodilia
34:21
Birds
36:09
Birds and Dinosaurs
36:18
Theropods
38:00
Birds: High Metabolism, Respiratory System, Lungs, and Heart
39:04
Birds: Endothermic, Bones, and Feathers
40:15
Mammals
42:33
Mammals Overview
42:35
Diaphragm and Heart
42:57
Diphydont
43:44
Synapsids
44:41
Monotremes
46:36
Monotremes
46:37
Marsupials
47:12
Marsupials: Definition and Examples
47:16
Convergent Evolution
48:09
Eutherians (Placental Mammals)
49:42
Placenta
49:43
Order Carnivora
50:48
Order Raodentia
51:00
Order Cetaceans
51:14
Primates
51:41
Primates Overview
51:42
Nails and Hands
51:58
Vision
52:51
Social Care for Young
53:28
Brain
53:43
Example 1: Distinguishing Characteristics of Chordates
54:33
Example 2: Match Description to Correct Term
55:56
Example 3: Bird's Anatomy
57:38
Example 4: Vertebrate Animal, Marine Environment, and Ectothermic
59:14
IX. Plants
Seedless Plants

34m 31s

Intro
0:00
Origin and Classification of Plants
0:06
Origin and Classification of Plants
0:07
Non-Vascular vs. Vascular Plants
1:29
Seedless Vascular & Seed Plants
2:28
Angiosperms & Gymnosperms
2:50
Alternation of Generations
3:54
Alternation of Generations
3:55
Bryophytes
7:58
Overview of Bryrophytes
7:59
Example: Moss Gametophyte
9:29
Example: Moss Sporophyte
9:50
Moss Life Cycle
10:12
Moss Life Cycle
10:13
Seedless Vascular Plants
13:23
Vascular Structures: Cell Walls, and Lignin
13:24
Homosporous
17:11
Heterosporous
17:48
Adaptations to Life on land
21:10
Adaptation 1: Cell Walls
21:38
Adaptation 2: Vascular Plants
21:59
Adaptation 3 : Xylem & Phloem
22:31
Adaptation 4: Seeds
23:07
Adaptation 5: Pollen
23:35
Adaptation 6: Stomata
24:45
Adaptation 7: Reduced Gametophyte Generation
25:32
Example 1: Bryophytes
26:39
Example 2: Sporangium, Lignin, Gametophyte, and Antheridium
28:34
Example 3: Adaptations to Life on Land
29:47
Example 4: Life Cycle of Plant
32:06
Plant Structure

1h 1m 21s

Intro
0:00
Plant Tissue
0:05
Dermal Tissue
0:15
Vascular Tissue
0:39
Ground Tissue
1:31
Cell Types in Plants
2:14
Parenchyma Cells
2:24
Collenchyma Cells
3:21
Sclerenchyma Cells
3:59
Xylem
5:04
Xylem: Tracheids and Vessel Elements
6:12
Gymnosperms vs. Angiosperms
7:53
Phloem
8:37
Phloem: Structures and Function
8:38
Sieve-Tube Elements
8:45
Companion Cells & Sieve Plates
9:11
Roots
10:08
Taproots & Fibrous
10:09
Aerial Roots & Prop Roots
11:41
Structures and Functions of Root: Dicot & Monocot
13:00
Pericyle
16:57
The Nitrogen Cylce
18:05
The Nitrogen Cycle
18:06
Mycorrhizae
24:20
Mycorrhizae
24:23
Ectomycorrhiza
26:03
Endomycorrhiza
26:25
Stems
26:53
Stems
26:54
Vascular Bundles of Monocots and Dicots
28:18
Leaves
29:48
Blade & Petiole
30:13
Upper Epidermis, Lower Epidermis & Cuticle
30:39
Ground Tissue, Palisade Mesophyll, Spongy Mesophyll
31:35
Stomata Pores
33:23
Guard Cells
34:15
Vascular Tissues: Vascular Bundles and Bundle Sheath
34:46
Stomata
36:12
Stomata & Gas Exchange
36:16
Guard Cells, Flaccid, and Turgid
36:43
Water Potential
38:03
Factors for Opening Stoma
40:35
Factors Causing Stoma to Close
42:44
Overview of Plant Growth
44:23
Overview of Plant Growth
44:24
Primary Plant Growth
46:19
Apical Meristems
46:25
Root Growth: Zone of Cell Division
46:44
Root Growth: Zone of Cell Elongation
47:35
Root Growth: Zone of Cell Differentiation
47:55
Stem Growth: Leaf Primodia
48:16
Secondary Plant Growth
48:48
Secondary Plant Growth Overview
48:59
Vascular Cambium: Secondary Xylem and Phloem
49:38
Cork Cambium: Periderm and Lenticels
51:10
Example 1: Leaf Structures
53:30
Example 2: List Three Types of Plant Tissue and their Major Functions
55:13
Example 3: What are Two Factors that Stimulate the Opening or Closing of Stomata?
56:58
Example 4: Plant Growth
59:18
Gymnosperms and Angiosperms

1h 1m 51s

Intro
0:00
Seed Plants
0:22
Sporopollenin
0:58
Heterosporous: Megasporangia
2:49
Heterosporous: Microsporangia
3:19
Gymnosperms
5:20
Gymnosperms
5:21
Gymnosperm Life Cycle
7:30
Gymnosperm Life Cycle
7:31
Flower Structure
15:15
Petal & Pollination
15:48
Sepal
16:52
Stamen: Anther, Filament
17:05
Pistill: Stigma, Style, Ovule, Ovary
17:55
Complete Flowers
20:14
Angiosperm Gametophyte Formation
20:47
Male Gametophyte: Microsporocytes, Microsporangia & Meiosis
20:57
Female Gametophyte: Megasporocytes & Meiosis
24:22
Double Fertilization
25:43
Double Fertilization: Pollen Tube and Endosperm
25:44
Angiosperm Life Cycle
29:43
Angiosperm Life Cycle
29:48
Seed Structure and Development
33:37
Seed Structure and Development
33:38
Pollen Dispersal
37:53
Abiotic
38:28
Biotic
39:30
Prevention of Self-Pollination
40:48
Mechanism 1
41:08
Mechanism 2: Dioecious
41:37
Mechanism 3
42:32
Self-Incompatibility
43:08
Gametophytic Self-Incompatibility
44:38
Sporophytic Self-Incompatibility
46:50
Asexual Reproduction
48:33
Asexual Reproduction & Vegetative Propagation
48:34
Graftiry
50:19
Monocots and Dicots
51:34
Monocots vs.Dicots
51:35
Example 1: Double Fertilization
54:43
Example 2: Mechanisms of Self-Fertilization
56:02
Example 3: Monocots vs. Dicots
58:11
Example 4: Flower Structures
1:00:11
Transport of Nutrients and Water in Plants

40m 30s

Intro
0:00
Review of Plant Cell Structure
0:14
Cell Wall, Plasma Membrane, Middle lamella, and Cytoplasm
0:15
Plasmodesmata, Chloroplasts, and Central Vacuole
3:24
Water Absorption by Plants
4:28
Root Hairs and Mycorrhizae
4:30
Osmosis and Water Potential
5:41
Apoplast and Symplast Pathways
10:01
Apoplast and Symplast Pathways
10:02
Xylem Structure
21:02
Tracheids and Vessel Elements
21:03
Bulk Flow
23:00
Transpiration
23:26
Cohesion
25:10
Adhesion
26:10
Phloem Structure
27:25
Pholem
27:26
Sieve-Tube Elements
27:48
Companion Cells
28:17
Translocation
28:42
Sugar Source and Sugar Sink Overview
28:43
Example of Sugar Sink
30:01
Example of Sugar Source
30:48
Example 1: Match the Following Terms to their Description
33:17
Example 2: Water Potential
34:58
Example 3: Bulk Flow
36:56
Example 4: Sugar Sink and Sugar Source
38:33
Plant Hormones and Tropisms

48m 10s

Intro
0:00
Plant Cell Signaling
0:17
Plant Cell Signaling Overview
0:18
Step 1: Reception
1:03
Step 2: Transduction
2:32
Step 3: Response
2:58
Second Messengers
3:52
Protein Kinases
4:42
Auxins
6:14
Auxins
6:18
Indoleacetic Acid (IAA)
7:23
Cytokinins and Gibberellins
11:10
Cytokinins: Apical Dominance & Delay of Aging
11:16
Gibberellins: 'Bolting'
13:51
Ethylene
15:33
Ethylene
15:34
Positive Feedback
15:46
Leaf Abscission
18:05
Mechanical Stress: Triple Response
19:36
Abscisic Acid
21:10
Abscisic Acid
21:15
Tropisms
23:11
Positive Tropism
23:50
Negative Tropism
24:07
Statoliths
26:21
Phytochromes and Photoperiodism
27:48
Phytochromes: PR and PFR
27:56
Circadian Rhythms
32:06
Photoperiod
33:13
Photoperiodism
33:38
Gerner & Allard
34:35
Short-Day Plant
35:22
Long-Day Plant
37:00
Example 1: Plant Hormones
41:28
Example 2: Cytokinins & Gibberellins
43:00
Example 3: Match the Following Terms to their Description
44:46
Example 4: Hormones & Cell Response
46:14
X. Animal Structure and Physiology
The Respiratory System

48m 14s

Intro
0:00
Gas Exchange in Animals
0:17
Respiration
0:19
Ventilation
1:09
Characteristics of Respiratory Surfaces
1:53
Gas Exchange in Aquatic Animals
3:05
Simple Aquatic Animals
3:06
Gills & Gas Exchange in Complex Aquatic Animals
3:49
Countercurrent Exchange
6:12
Gas Exchange in Terrestrial Animals
13:46
Earthworms
14:07
Internal Respiratory
15:35
Insects
16:55
Circulatory Fluid
19:06
The Human Respiratory System
21:21
Nasal Cavity, Pharynx, Larynx, and Epiglottis
21:50
Bronchus, Bronchiole, Trachea, and Alveoli
23:38
Pulmonary Surfactants
28:05
Circulatory System: Hemoglobin
29:13
Ventilation
30:28
Inspiration/Expiration: Diaphragm, Thorax, and Abdomen
30:33
Breathing Control Center: Regulation of pH
34:34
Example 1: Tracheal System in Insects
39:08
Example 2: Countercurrent Exchange
42:09
Example 3: Respiratory System
44:10
Example 4: Diaphragm, Ventilation, pH, and Regulation of Breathing
45:31
The Circulatory System

1h 20m 21s

Intro
0:00
Types of Circulatory Systems
0:07
Circulatory System Overview
0:08
Open Circulatory System
3:19
Closed Circulatory System
5:58
Blood Vessels
7:51
Arteries
8:16
Veins
10:01
Capillaries
12:35
Vasoconstriction and Vasodilation
13:10
Vasoconstriction
13:11
Vasodilation
13:47
Thermoregulation
14:32
Blood
15:53
Plasma
15:54
Cellular Component: Red Blood Cells
17:41
Cellular Component: White Blood Cells
20:18
Platelets
21:14
Blood Types
21:35
Clotting
27:04
Blood, Fibrin, and Clotting
27:05
Hemophilia
30:26
The Heart
31:09
Structures and Functions of the Heart
31:19
Pulmonary and Systemic Circulation
40:20
Double Circuit: Pulmonary Circuit and Systemic Circuit
40:21
The Cardiac Cycle
42:35
The Cardiac Cycle
42:36
Autonomic Nervous System
50:00
Hemoglobin
51:25
Hemoglobin & Hemocyanin
51:26
Oxygen-Hemoglobin Dissociation Curve
55:30
Oxygen-Hemoglobin Dissociation Curve
55:44
Transport of Carbon Dioxide
1:06:31
Transport of Carbon Dioxide
1:06:37
Example 1: Pathway of Blood
1:12:48
Example 2: Oxygenated Blood, Pacemaker, and Clotting
1:15:24
Example 3: Vasodilation and Vasoconstriction
1:16:19
Example 4: Oxygen-Hemoglobin Dissociation Curve
1:18:13
The Digestive System

56m 11s

Intro
0:00
Introduction to Digestion
0:07
Digestive Process
0:08
Intracellular Digestion
0:45
Extracellular Digestion
1:44
Types of Digestive Tracts
2:08
Gastrovascular Cavity
2:09
Complete Gastrointestinal Tract (Alimentary Canal)
3:54
'Crop'
4:43
The Human Digestive System
5:41
Structures of the Human Digestive System
5:47
The Oral Cavity and Esophagus
7:47
Mechanical & Chemical Digestion
7:48
Salivary Glands
8:55
Pharynx and Epigloltis
9:43
Peristalsis
11:35
The Stomach
12:57
Lower Esophageal Sphincter
13:00
Gastric Gland, Parietal Cells, and Pepsin
14:32
Mucus Cell
15:48
Chyme & Pyloric Sphincter
17:32
The Pancreas
18:31
Endocrine and Exocrine
19:03
Amylase
20:05
Proteases
20:51
Lipases
22:20
The Liver
23:08
The Liver & Production of Bile
23:09
The Small Intestine
24:37
The Small Intestine
24:38
Duodenum
27:44
Intestinal Enzymes
28:41
Digestive Enzyme
33:30
Site of Production: Mouth
33:43
Site of Production: Stomach
34:03
Site of Production: Pancreas
34:16
Site of Production: Small Intestine
36:18
Absorption of Nutrients
37:51
Absorption of Nutrients: Jejunum and Ileum
37:52
The Large Intestine
44:52
The Large Intestine: Colon, Cecum, and Rectum
44:53
Regulation of Digestion by Hormones
46:55
Gastrin
47:21
Secretin
47:50
Cholecystokinin (CCK)
48:00
Example 1: Intestinal Cell, Bile, and Digestion of Fats
48:29
Example 2: Matching
51:06
Example 3: Digestion and Absorption of Starch
52:18
Example 4: Large Intestine and Gastric Fluids
54:52
The Excretory System

1h 12m 14s

Intro
0:00
Nitrogenous Wastes
0:08
Nitrogenous Wastes Overview
0:09
NH3
0:39
Urea
2:43
Uric Acid
3:31
Osmoregulation
4:56
Osmoregulation
5:05
Saltwater Fish vs. Freshwater Fish
8:58
Types of Excretory Systems
13:42
Protonephridia
13:50
Metanephridia
16:15
Malpighian Tubule
19:05
The Human Excretory System
20:45
Kidney, Ureter, bladder, Urethra, Medula, and Cortex
20:53
Filtration, Reabsorption and Secretion
22:53
Filtration
22:54
Reabsorption
24:16
Secretion
25:20
The Nephron
26:23
The Nephron
26:24
The Nephron, cont.
41:45
Descending Loop of Henle
41:46
Ascending Loop of Henle
45:45
Antidiuretic Hormone
54:30
Antidiuretic Hormone (ADH)
54:31
Aldosterone
58:58
Aldosterone
58:59
Example 1: Nephron of an Aquatic Mammal
1:04:21
Example 2: Uric Acid & Saltwater Fish
1:06:36
Example 3: Nephron
1:09:14
Example 4: Gastrointestinal Infection
1:10:41
The Endocrine System

51m 12s

Intro
0:00
The Endocrine System Overview
0:07
Thyroid
0:08
Exocrine
1:56
Pancreas
2:44
Paracrine Signaling
4:06
Pheromones
5:15
Mechanisms of Hormone Action
6:06
Reception, Transduction, and Response
7:06
Classes of Hormone
10:05
Negative Feedback: Testosterone Example
12:16
The Pancreas
15:11
The Pancreas & islets of Langerhan
15:12
Insulin
16:02
Glucagon
17:28
The Anterior Pituitary
19:25
Thyroid Stimulating Hormone
20:24
Adrenocorticotropic Hormone
21:16
Follide Stimulating Hormone
22:04
Luteinizing Hormone
22:45
Growth Hormone
23:45
Prolactin
24:24
Melanocyte Stimulating Hormone
24:55
The Hypothalamus and Posterior Pituitary
25:45
Hypothalamus, Oxytocin, Antidiuretic Hormone (ADH), and Posterior Pituitary
25:46
The Adrenal Glands
31:20
Adrenal Cortex
31:56
Adrenal Medulla
34:29
The Thyroid
35:54
Thyroxine
36:09
Calcitonin
40:27
The Parathyroids
41:44
Parathyroids Hormone (PTH)
41:45
The Ovaries and Testes
43:32
Estrogen, Progesterone, and Testosterone
43:33
Example 1: Match the Following Hormones with their Descriptions
45:38
Example 2: Pancreas, Endocrine Organ & Exocrine Organ
47:06
Example 3: Insulin and Glucagon
48:28
Example 4: Increased Level of Cortisol in Blood
50:25
The Nervous System

1h 10m 38s

Intro
0:00
Types of Nervous Systems
0:28
Nerve Net
0:37
Flatworm
1:07
Cephalization
1:52
Arthropods
2:44
Echinoderms
3:11
Nervous System Organization
3:40
Nervous System Organization Overview
3:41
Automatic Nervous System: Sympathetic & Parasympathetic
4:42
Neuron Structure
6:57
Cell Body & Dendrites
7:16
Axon & Axon Hillock
8:20
Synaptic Terminals, Mylenin, and Nodes of Ranvier
9:01
Pre-synaptic and Post-synaptic Cells
10:16
Pre-synaptic Cells
10:17
Post-synaptic Cells
11:05
Types of Neurons
11:50
Sensory Neurons
11:54
Motor Neurons
13:12
Interneurons
14:24
Resting Potential
15:14
Membrane Potential
15:25
Resting Potential: Chemical Gradient
16:06
Resting Potential: Electrical Gradient
19:18
Gated Ion Channels
24:40
Voltage-Gated & Ligand-Gated Ion Channels
24:48
Action Potential
30:09
Action Potential Overview
30:10
Step 1
32:07
Step 2
32:17
Step 3
33:12
Step 4
35:14
Step 5
36:39
Action Potential Transmission
39:04
Action Potential Transmission
39:05
Speed of Conduction
41:19
Saltatory Conduction
42:58
The Synapse
44:17
The Synapse: Presynaptic & Postsynaptic Cell
44:31
Examples of Neurotransmitters
50:05
Brain Structure
51:57
Meniges
52:19
Cerebrum
52:56
Corpus Callosum
53:13
Gray & White Matter
53:38
Cerebral Lobes
55:35
Cerebellum
56:00
Brainstem
56:30
Medulla
56:51
Pons
57:22
Midbrain
57:55
Thalamus
58:25
Hypothalamus
58:58
Ventricles
59:51
The Spinal Cord
1:00:29
Sensory Stimuli
1:00:30
Reflex Arc
1:01:41
Example 1: Automatic Nervous System
1:04:38
Example 2: Synaptic Terminal and the Release of Neurotransmitters
1:06:22
Example 3: Volted-Gated Ion Channels
1:08:00
Example 4: Neuron Structure
1:09:26
Musculoskeletal System

39m 29s

Intro
0:00
Skeletal System Types and Function
0:30
Skeletal System
0:31
Exoskeleton
1:34
Endoskeleton
2:32
Skeletal System Components
2:55
Bone
3:06
Cartilage
5:04
Tendons
6:18
Ligaments
6:34
Skeletal Muscle
6:52
Skeletal Muscle
7:24
Sarcomere
9:50
The Sliding Filament Theory
13:12
The Sliding Filament Theory: Muscle Contraction
13:13
The Neuromuscular Junction
17:24
The Neuromuscular Junction: Motor Neuron & Muscle Fiber
17:26
Sarcolemma, Sarcoplasmic
21:54
Tropomyosin & Troponin
23:35
Summation and Tetanus
25:26
Single Twitch, Summation of Two Twitches, and Tetanus
25:27
Smooth Muscle
28:50
Smooth Muscle
28:58
Cardiac Muscle
30:40
Cardiac Muscle
30:42
Summary of Muscle Types
32:07
Summary of Muscle Types
32:08
Example 1: Contraction and Skeletal Muscle
33:15
Example 2: Skeletal Muscle and Smooth Muscle
36:23
Example 3: Muscle Contraction, Bone, and Nonvascularized Connective Tissue
37:31
Example 4: Sarcomere
38:17
The Immune System

1h 24m 28s

Intro
0:00
The Lymphatic System
0:16
The Lymphatic System Overview
0:17
Function 1
1:23
Function 2
2:27
Barrier Defenses
3:41
Nonspecific vs. Specific Immune Defenses
3:42
Barrier Defenses
5:12
Nonspecific Cellular Defenses
7:50
Nonspecific Cellular Defenses Overview
7:53
Phagocytes
9:29
Neutrophils
11:43
Macrophages
12:15
Natural Killer Cells
12:55
Inflammatory Response
14:19
Complement
18:16
Interferons
18:40
Specific Defenses - Acquired Immunity
20:12
T lymphocytes and B lymphocytes
20:13
B Cells
23:35
B Cells & Humoral Immunity
23:41
Clonal Selection
29:50
Clonal Selection
29:51
Primary Immune Response
34:28
Secondary Immune Response
35:31
Cytotoxic T Cells
38:41
Helper T Cells
39:20
Major Histocompatibility Complex Molecules
40:44
Major Histocompatibility Complex Molecules
40:55
Helper T Cells
52:36
Helper T Cells
52:37
Mechanisms of Antibody Action
59:00
Mechanisms of Antibody Action
59:01
Opsonization
1:00:01
Complement System
1:01:57
Classes of Antibodies
1:02:45
IgM
1:03:01
IgA
1:03:17
IgG
1:03:53
IgE
1:04:10
Passive and Active Immunity
1:05:00
Passive Immunity
1:05:01
Active Immunity
1:07:49
Recognition of Self and Non-Self
1:09:32
Recognition of Self and Non-Self
1:09:33
Self-Tolerance & Autoimmune Diseases
1:10:50
Immunodeficiency
1:13:27
Immunodeficiency
1:13:28
Chemotherapy
1:13:56
AID
1:14:27
Example 1: Match the Following Terms with their Descriptions
1:15:26
Example 2: Three Components of Non-specific Immunity
1:17:59
Example 3: Immunodeficient
1:21:19
Example 4: Self-tolerance and Autoimmune Diseases
1:23:07
XI. Animal Reproduction and Development
Reproduction

1h 1m 41s

Intro
0:00
Asexual Reproduction
0:17
Fragmentation
0:53
Fission
1:54
Parthenogenesis
2:38
Sexual Reproduction
4:00
Sexual Reproduction
4:01
Hermaphrodite
8:08
The Male Reproduction System
8:54
Seminiferous Tubules & Leydig Cells
8:55
Epididymis
9:48
Seminal Vesicle
11:19
Bulbourethral
12:37
The Female Reproductive System
13:25
Ovaries
13:28
Fallopian
14:50
Endometrium, Uterus, Cilia, and Cervix
15:03
Mammary Glands
16:44
Spermatogenesis
17:08
Spermatogenesis
17:09
Oogenesis
21:01
Oogenesis
21:02
The Menstrual Cycle
27:56
The Menstrual Cycle: Ovarian and Uterine Cycle
27:57
Summary of the Ovarian and Uterine Cycles
42:54
Ovarian
42:55
Uterine
44:51
Oxytocin and Prolactin
46:33
Oxytocin
46:34
Prolactin
47:00
Regulation of the Male Reproductive System
47:28
Hormones: GnRH, LH, FSH, and Testosterone
47:29
Fertilization
50:11
Fertilization
50:12
Structures of Egg
50:28
Acrosomal Reaction
51:36
Cortical Reaction
53:09
Example 1: List Three Differences between Spermatogenesis and oogenesis
55:36
Example 2: Match the Following Terms to their Descriptions
57:34
Example 3: Pregnancy and the Ovarian Cycle
58:44
Example 4: Hormone
1:00:43
Development

50m 5s

Intro
0:00
Cleavage
0:31
Cleavage
0:32
Meroblastic
2:06
Holoblastic Cleavage
3:23
Protostomes
4:34
Deuterostomes
5:13
Totipotent
5:52
Blastula Formation
6:42
Blastula
6:46
Gastrula Formation
8:12
Deuterostomes
11:02
Protostome
11:44
Ectoderm
12:17
Mesoderm
12:55
Endoderm
13:40
Cytoplasmic Determinants
15:19
Cytoplasmic Determinants
15:23
The Bird Embryo
22:52
Cleavage
23:35
Blastoderm
23:55
Primitive Streak
25:38
Migration and Differentiation
27:09
Extraembryonic Membranes
28:33
Extraembryonic Membranes
28:34
Chorion
30:02
Yolk Sac
30:36
Allantois
31:04
The Mammalian Embryo
32:18
Cleavage
32:28
Blastocyst
32:44
Trophoblast
34:37
Following Implantation
35:48
Organogenesis
37:04
Organogenesis, Notochord and Neural Tube
37:05
Induction
40:15
Induction
40:39
Fate Mapping
41:40
Example 1: Processes and Stages of Embryological Development
42:49
Example 2: Transplanted Cells
44:33
Example 3: Germ Layer
46:41
Example 4: Extraembryonic Membranes
47:28
XII. Animal Behavior
Animal Behavior

47m 48s

Intro
0:00
Introduction to Animal Behavior
0:05
Introduction to Animal Behavior
0:06
Ethology
1:04
Proximate Cause & Ultimate Cause
1:46
Fixed Action Pattern
3:07
Sign Stimulus
3:40
Releases and Example
3:55
Exploitation and Example
7:23
Learning
8:56
Habituation, Associative Learning, and Imprinting
8:57
Habituation
10:03
Habituation: Definition and Example
10:04
Associative Learning
11:47
Classical
12:19
Operant Conditioning
13:40
Positive & Negative Reinforcement
14:59
Positive & Negative Punishment
16:13
Extinction
17:28
Imprinting
17:47
Imprinting: Definition and Example
17:48
Social Behavior
20:12
Cooperation
20:38
Agonistic
21:37
Dorminance Heirarchies
23:23
Territoriality
24:08
Altruism
24:55
Communication
26:56
Communication
26:57
Mating
32:38
Mating Overview
32:40
Promiscuous
33:13
Monogamous
33:32
Polygamous
33:48
Intrasexual
34:22
Intersexual Selection
35:08
Foraging
36:08
Optimal Foraging Model
36:39
Foraging
37:47
Movement
39:12
Kinesis
39:20
Taxis
40:17
Migration
40:54
Lunar Cycles
42:02
Lunar Cycles
42:08
Example 1: Types of Conditioning
43:19
Example 2: Match the Following Terms to their Descriptions
44:12
Example 3: How is the Optimal Foraging Model Used to Explain Foraging Behavior
45:47
Example 4: Learning
46:54
XIII. Ecology
Biomes

58m 49s

Intro
0:00
Ecology
0:08
Ecology
0:14
Environment
0:22
Integrates
1:41
Environment Impacts
2:20
Population and Distribution
3:20
Population
3:21
Range
4:50
Potential Range
5:10
Abiotic
5:46
Biotic
6:22
Climate
7:55
Temperature
8:40
Precipitation
10:00
Wind
10:37
Sunlight
10:54
Macroclimates & Microclimates
11:31
Other Abiotic Factors
12:20
Geography
12:28
Water
13:17
Soil and Rocks
13:48
Sunlight
14:42
Sunlight
14:43
Seasons
15:43
June Solstice, December Solstice, March Equinox, and September Equinox
15:44
Tropics
19:00
Seasonability
19:39
Wind and Weather Patterns
20:44
Vertical Circulation
20:51
Surface Wind Patterns
25:18
Local Climate Effects
26:51
Local Climate Effects
26:52
Terrestrial Biomes
30:04
Biome
30:05
Forest
31:02
Tropical Forest
32:00
Tropical Forest
32:01
Temperate Broadleaf Forest
32:55
Temperate Broadleaf Forest
32:56
Coniferous/Taiga Forest
34:10
Coniferous/Taiga Forest
34:11
Desert
36:05
Desert
36:06
Grassland
37:45
Grassland
37:46
Tundra
40:09
Tundra
40:10
Freshwater Biomes
42:25
Freshwater Biomes: Zones
42:27
Eutrophic Lakes
44:24
Oligotrophic Lakes
45:01
Lakes Turnover
46:03
Rivers
46:51
Wetlands
47:40
Estuary
48:11
Marine Biomes
48:45
Marine Biomes: Zones
48:46
Example 1: Diversity of Life
52:18
Example 2: Marine Biome
53:08
Example 3: Season
54:20
Example 4: Biotic vs. Abiotic
55:54
Population

41m 16s

Intro
0:00
Population
0:07
Size 'N'
0:16
Density
0:41
Dispersion
1:01
Measure Population: Count Individuals, Sampling, and Proxymeasure
2:26
Mortality
7:29
Mortality and Survivorship
7:30
Age Structure Diagrams
11:52
Expanding with Rapid Growth, Expanding, and Stable
11:58
Population Growth
15:39
Biotic Potential & Exponential Growth
15:43
Logistic Population Growth
19:07
Carrying Capacity (K)
19:18
Limiting Factors
20:55
Logistic Model and Oscillation
22:55
Logistic Model and Oscillation
22:56
Changes to the Carrying Capacity
24:36
Changes to the Carrying Capacity
24:37
Growth Strategies
26:07
'r-selected' or 'r-strategist'
26:23
'K-selected' or 'K-strategist'
27:47
Human Population
30:15
Human Population and Exponential Growth
30:21
Case Study - Lynx and Hare
31:54
Case Study - Lynx and Hare
31:55
Example 1: Estimating Population Size
34:35
Example 2: Population Growth
36:45
Example 3: Carrying Capacity
38:17
Example 4: Types of Dispersion
40:15
Communities

1h 6m 26s

Intro
0:00
Community
0:07
Ecosystem
0:40
Interspecific Interactions
1:14
Competition
2:45
Competition Overview
2:46
Competitive Exclusion
3:57
Resource Partitioning
4:45
Character Displacement
6:22
Predation
7:46
Predation
7:47
True Predation
8:05
Grazing/ Herbivory
8:39
Predator Adaptation
10:13
Predator Strategies
10:22
Physical Features
11:02
Prey Adaptation
12:14
Prey Adaptation
12:23
Aposematic Coloration
13:35
Batesian Mimicry
14:32
Size
15:42
Parasitism
16:48
Symbiotic Relationship
16:54
Ectoparasites
18:31
Endoparasites
18:53
Hyperparisitism
19:21
Vector
20:08
Parasitoids
20:54
Mutualism
21:23
Resource - Resource mutualism
21:34
Service - Resource Mutualism
23:31
Service - Service Mutualism: Obligate & Facultative
24:23
Commensalism
26:01
Commensalism
26:03
Symbiosis
27:31
Trophic Structure
28:35
Producers & Consumers: Autotrophs & Heterotrophs
28:36
Food Chain
33:26
Producer & Consumers
33:38
Food Web
39:01
Food Web
39:06
Significant Species within Communities
41:42
Dominant Species
41:50
Keystone Species
42:44
Foundation Species
43:41
Community Dynamics and Disturbances
44:31
Disturbances
44:33
Duration
47:01
Areal Coverage
47:22
Frequency
47:48
Intensity
48:04
Intermediate Level of Disturbance
48:20
Ecological Succession
50:29
Primary and Secondary Ecological Succession
50:30
Example 1: Competition Situation & Outcome
57:18
Example 2: Food Chains
1:00:08
Example 3: Ecological Units
1:02:44
Example 4: Disturbances & Returning to the Original Climax Community
1:04:30
Energy and Ecosystems

57m 42s

Intro
0:00
Ecosystem: Biotic & Abiotic Components
0:15
First Law of Thermodynamics & Energy Flow
0:40
Gross Primary Productivity (GPP)
3:52
Net Primary Productivity (NPP)
4:50
Biogeochemical Cycles
7:16
Law of Conservation of Mass & Biogeochemical Cycles
7:17
Water Cycle
10:55
Water Cycle
10:57
Carbon Cycle
17:52
Carbon Cycle
17:53
Nitrogen Cycle
22:40
Nitrogen Cycle
22:41
Phosphorous Cycle
29:34
Phosphorous Cycle
29:35
Climate Change
33:20
Climate Change
33:21
Eutrophication
39:38
Nitrogen
40:34
Phosphorous
41:29
Eutrophication
42:55
Example 1: Energy and Ecosystems
45:28
Example 2: Atmospheric CO2
48:44
Example 3: Nitrogen Cycle
51:22
Example 4: Conversion of a Forest near a Lake to Farmland
53:20
XIV. Laboratory Review
Laboratory Review

2h 4m 30s

Intro
0:00
Lab 1: Diffusion and Osmosis
0:09
Lab 1: Diffusion and Osmosis
0:10
Lab 1: Water Potential
11:55
Lab 1: Water Potential
11:56
Lab 2: Enzyme Catalysis
18:30
Lab 2: Enzyme Catalysis
18:31
Lab 3: Mitosis and Meiosis
27:40
Lab 3: Mitosis and Meiosis
27:41
Lab 3: Mitosis and Meiosis
31:50
Ascomycota Life Cycle
31:51
Lab 4: Plant Pigments and Photosynthesis
40:36
Lab 4: Plant Pigments and Photosynthesis
40:37
Lab 5: Cell Respiration
49:56
Lab 5: Cell Respiration
49:57
Lab 6: Molecular Biology
55:06
Lab 6: Molecular Biology & Transformation 1st Part
55:07
Lab 6: Molecular Biology
1:01:16
Lab 6: Molecular Biology 2nd Part
1:01:17
Lab 7: Genetics of Organisms
1:07:32
Lab 7: Genetics of Organisms
1:07:33
Lab 7: Chi-square Analysis
1:13:00
Lab 7: Chi-square Analysis
1:13:03
Lab 8: Population Genetics and Evolution
1:20:41
Lab 8: Population Genetics and Evolution
1:20:42
Lab 9: Transpiration
1:24:02
Lab 9: Transpiration
1:24:03
Lab 10: Physiology of the Circulatory System
1:31:05
Lab 10: Physiology of the Circulatory System
1:31:06
Lab 10: Temperature and Metabolism in Ectotherms
1:38:25
Lab 10: Temperature and Metabolism in Ectotherms
1:38:30
Lab 11: Animal Behavior
1:40:52
Lab 11: Animal Behavior
1:40:53
Lab 12: Dissolved Oxygen & Aquatic Primary Productivity
1:45:36
Lab 12: Dissolved Oxygen & Aquatic Primary Productivity
1:45:37
Lab 12: Primary Productivity
1:49:06
Lab 12: Primary Productivity
1:49:07
Example 1: Chi-square Analysis
1:56:31
Example 2: Mitosis
1:59:28
Example 3: Transpiration of Plants
2:00:27
Example 4: Population Genetic
2:01:16
XV. The AP Biology Test
Understanding the Basics

13m 2s

Intro
0:00
AP Biology Structure
0:18
Section I
0:31
Section II
1:16
Scoring
2:04
The Four 'Big Ideas'
3:51
Process of Evolution
4:37
Biological Systems Utilize
4:44
Living Systems
4:55
Biological Systems Interact
5:03
Items to Bring to the Test
7:56
Test Taking Tips
9:53
XVI. Practice Test (Barron's 4th Edition)
AP Biology Practice Exam: Section I, Part A, Multiple Choice Questions 1-31

1h 4m 29s

Intro
0:00
AP Biology Practice Exam
0:14
Multiple Choice 1
0:40
Multiple Choice 2
2:27
Multiple Choice 3
4:30
Multiple Choice 4
6:43
Multiple Choice 5
9:27
Multiple Choice 6
11:32
Multiple Choice 7
12:54
Multiple Choice 8
14:42
Multiple Choice 9
17:06
Multiple Choice 10
18:42
Multiple Choice 11
20:49
Multiple Choice 12
23:23
Multiple Choice 13
26:20
Multiple Choice 14
27:52
Multiple Choice 15
28:44
Multiple Choice 16
33:07
Multiple Choice 17
35:31
Multiple Choice 18
39:43
Multiple Choice 19
40:37
Multiple Choice 20
42:47
Multiple Choice 21
45:58
Multiple Choice 22
49:49
Multiple Choice 23
53:44
Multiple Choice 24
55:12
Multiple Choice 25
55:59
Multiple Choice 26
56:50
Multiple Choice 27
58:08
Multiple Choice 28
59:54
Multiple Choice 29
1:01:36
Multiple Choice 30
1:02:31
Multiple Choice 31
1:03:50
AP Biology Practice Exam: Section I, Part A, Multiple Choice Questions 32-63

50m 44s

Intro
0:00
AP Biology Practice Exam
0:14
Multiple Choice 32
0:27
Multiple Choice 33
4:14
Multiple Choice 34
5:12
Multiple Choice 35
6:51
Multiple Choice 36
10:46
Multiple Choice 37
11:27
Multiple Choice 38
12:17
Multiple Choice 39
13:49
Multiple Choice 40
17:02
Multiple Choice 41
18:27
Multiple Choice 42
19:35
Multiple Choice 43
21:10
Multiple Choice 44
23:35
Multiple Choice 45
25:00
Multiple Choice 46
26:20
Multiple Choice 47
28:40
Multiple Choice 48
30:14
Multiple Choice 49
31:24
Multiple Choice 50
32:45
Multiple Choice 51
33:41
Multiple Choice 52
34:40
Multiple Choice 53
36:12
Multiple Choice 54
38:06
Multiple Choice 55
38:37
Multiple Choice 56
40:00
Multiple Choice 57
41:18
Multiple Choice 58
43:12
Multiple Choice 59
44:25
Multiple Choice 60
45:02
Multiple Choice 61
46:10
Multiple Choice 62
47:54
Multiple Choice 63
49:01
AP Biology Practice Exam: Section I, Part B, Grid In

21m 52s

Intro
0:00
AP Biology Practice Exam
0:17
Grid In Question 1
0:29
Grid In Question 2
3:49
Grid In Question 3
11:04
Grid In Question 4
13:18
Grid In Question 5
17:01
Grid In Question 6
19:30
AP Biology Practice Exam: Section II, Long Free Response Questions

31m 22s

Intro
0:00
AP Biology Practice Exam
0:18
Free Response 1
0:29
Free Response 2
20:47
AP Biology Practice Exam: Section II, Short Free Response Questions

24m 41s

Intro
0:00
AP Biology Practice Exam
0:15
Free Response 3
0:26
Free Response 4
5:21
Free Response 5
8:25
Free Response 6
11:38
Free Response 7
14:48
Free Response 8
22:14
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Lecture Comments (23)

0 answers

Post by Jayanta Rege on October 29, 2015

At 39:58, you say that the Calvin Cycle requires 9 ATP's and 6 NADPH's per molecule of PGAL used for production of glucose. But we need 2 molecules of PGAL to make glucose, so wouldn't we need a total of 18 ATP and 12 NADPH and not 18 ATP and 6 NADPH, as you stated?

0 answers

Post by Melika Shayegh on September 25, 2015

Hi Dr. Eaton
Per molecule of pgal we need 9atps and 6 nadphs. Therefore for 1 molecule of glucose we need 18atps and 12 nadphs
Right?

0 answers

Post by Okwudili Ezeh on August 26, 2015

If making 1 G3p molecule requires 9ATP and 6NADPHs, how is it that 2 G3p molecules will require 18ATPs and 6 NADPHs? Should it not be 18ATPs and 12 NADPHs?

0 answers

Post by Okwudili Ezeh on August 26, 2015

If making 1 G3p molecule requires 9ATP and 6NADPHs, how is it that 2 G3p molecules will require 18ATPs and 6 NADPHs? Should it not be 18ATPs and 12 NADPHs?

0 answers

Post by Okwudili Ezeh on August 26, 2015

If making 1 G3p molecule requires 9ATP and 6NADPHs, how is it that 2 G3p molecules will require 18ATPs and 6 NADPHs? Should it not be 18ATPs and 12 NADPHs?

0 answers

Post by Stephanie Dean on September 30, 2014

At minute 40:05 you say that it takes two PGAL's to have enough carbon to make a glucose. This makes me think you need double the number of ATP's and NADPH's to make one glucose molecule due to needing two PGAL's. However at that time you say that it takes 18 ATP's and still only 6 NADPH's to make a glucose. Am I just overthinking this?

0 answers

Post by James Rodriguez-Hughes on August 7, 2014

Last part of Calvin cycle slide around 40:10. 6 or 12 NADPH?

0 answers

Post by sasank v on July 26, 2014

Dr Eaton
I have one quick question: 1) In the C4 and CAM plants- Does the water molecule splits into oxygen? If not, then how does C4 and CAM plants produce oxygen?

Thank you.

0 answers

Post by sasank v on July 23, 2014

Hi
I have one quick question: 1) In the C4 and CAM plants- Does the water molecule splits into oxygen? If not, then how does C4 and CAM plants produce oxygen?

Thank you.

0 answers

Post by Naveed Ahmad on June 28, 2014

At 39:45 there is a mistake in the Number of ATP. We Only need 7 ATP per PGAL:
a) 6ATP ; 6*[3-Phosphoglycerate] + 6ATP ---> 6*[1,3Bisphosphoglycerate]
b) 1ATP ; 5*[PGAL] + 1ATP ---> 3*[Ribulose-1,5-Bisphosphate]
  Total: 7ATP
If you focus on second reaction (b) 5*[PGAL] already have Pi so it will only need 1 more Pi to have a total of 6Pi in 3*[Ribulose-1,5-Bisphosphate].
So by this way it would need 14ATP per Glucose molecule.
The video tell that it require 6NADP+ per PGAL so it would then need 12NADP+ per Glucose molecule.
Thanks

1 answer

Last reply by: Dr Carleen Eaton
Wed Mar 26, 2014 6:50 PM

Post by Louis Brown on March 25, 2014

Dr. Carleen Eaton,
CAM plants fix CO2 as malic acid in the vacuoles of which cells? mesophyll or bundle sheath cells?
Thank you.

0 answers

Post by Akouvi Ognodo on November 12, 2013

Hello again Dr.Carleen,

I need help with these two questions. They have to do with photosynthesis

1- What happens to the time it takes for the leaf disks to float and why

2-What would happen to the rate of photosynthesis if the syringe was covered with a green plastic? with a red plastic?

Thank you.

2 answers

Last reply by: Akouvi Ognodo
Thu Nov 7, 2013 11:25 PM

Post by Akouvi Ognodo on October 17, 2013

Hello Dr. Carleen. If it takes 2pgals to have enough carbons to make a glucose, and if you have to use 18 ATPS, would you not need to use 12 NADPHAS (6*2)? You said, 6 NADPHs are needed.
Thank you.

1 answer

Last reply by: Yousra Hassan
Fri Dec 27, 2013 3:08 PM

Post by Michael Amin on January 20, 2013

Dr. Carleen,

Did you get your PHD 100 years ago because you look very young i cant believe it. The reason i say this is there is a problem in the very beginning of this lecture. "CO2 is used and oxygen is produced as a by product" This Statement would be incorrect the reason is.

The oxygen gas comes from water. A radioisotope of oxygen, oxygen-18, was used in a photosynthetic organism to trace the flow of the element. In one experiment, oxygen-18 was placed into water. In another experiment, oxygen-18 was placed into carbon dioxide. In the first experiment, the oxygen-18 ended up in the diatomic oxygen gas. In the second experiment, the oxygen-18 ended up in the saccharide and the water. This was done by a Doctor from Stanford University.

1 answer

Last reply by: Dr Carleen Eaton
Sun Oct 21, 2012 10:31 PM

Post by jessica chopra on October 15, 2012

How many calvin benson cycles eventually make one glucose molecule?

1 answer

Last reply by: Dr Carleen Eaton
Wed May 9, 2012 3:55 PM

Post by Gayatri Arumugam on May 5, 2012

Why is photolysis the spiting of water, shouldn't' be the plaiting of light? Photo means light and lysis means split. See time 21.45

0 answers

Post by Tanul Gupta on January 25, 2012

Don't you need 12 NADPH for one glucose?

Photosynthesis

  • Through photosynthesis, light energy is converted into chemical energy.
  • Chloroplasts are the site of photosynthesis. They are surrounded by a double membrane and contain a fluid called stroma. Stacks of thylakoids form grana.
  • Photosystems in the thylakoid membranes consist of a reaction-center complex and light harvesting complexes.
  • During the light reactions, light energy is used to produce ATP. ATP production may occur either via noncyclic photophosphorylation or cyclic photophosphorylation.
  • The reactions in the Calvin cycle are the light independent reactions (dark reactions).
  • CO2 enters the Calvin cycle and through a series of reactions a precursor to glucose is produced. The ATP and NADPH produced during the light reactions are required for the Calvin cycle.
  • Under hot, dry conditions, O2 may be fixed by rubisco, instead of CO2, in a process called photorespiration. This process does not produce glucose or ATP.
  • C4 plants and CAM plants have adaptations to minimize the occurance of photorespiration.

Photosynthesis

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
  • Photosynthesis 0:09
    • Introduction to Photosynthesis
    • Autotrophs and Heterotrophs
    • Overview of Photosynthesis Reaction
  • Leaf Anatomy and Chloroplast Structure 2:54
    • Chloroplast
    • Cuticle
    • Upper Epidermis
    • Mesophyll
    • Stomates
    • Guard Cells
    • Transpiration
    • Vascular Bundle
    • Stroma and Double Membrane
    • Grana
    • Thylakoids
    • Dark Reaction and Light Reaction
  • Light Reactions 8:43
    • Light Reactions
    • Pigments: Chlorophyll a, Chlorophyll b, and Carotenoids
    • Wave and Particle
    • Photon
  • Photosystems 13:24
    • Photosystems
    • Reaction-Center Complex and Light Harvesting Complexes
  • Noncyclic Photophosphorylation 17:46
    • Noncyclic Photophosphorylation Overview
    • What is Photophosphorylation?
    • Noncyclic Photophosphorylation Process
    • Photolysis and The Rest of Noncyclic Photophosphorylation
  • Cyclic Photophosphorylation 31:45
    • Cyclic Photophosphorylation
  • Light Independent Reactions 34:34
    • The Calvin Cycle
  • C3 Plants and Photorespiration 40:31
    • C3 Plants and Photorespiration
  • C4 Plants 45:32
    • C4 Plants: Structures and Functions
  • CAM Plants 50:25
    • CAM Plants: Structures and Functions
  • Example 1: Calvin Cycle 54:34
  • Example 2: C4 Plant 55:48
  • Example 3: Photosynthesis and Photorespiration 58:35
  • Example 4: CAM Plants 1:00:41

Transcription: Photosynthesis

Welcome to Educator.com.0000

In this last lecture in the series on cellular energetics, we will be focusing on the process of photosynthesis.0002

Photosynthesis is the process by which light energy is converted into chemical energy.0011

Plants, algae, cyanobacteria, and some protists are all capable of photosynthesis.0018

Photosynthetic organisms are known as autotrophs. These are producers of organic compounds.0025

In contrast, organisms such as animals and fungi that cannot produce organic compounds must consume other organisms for nutrients.0036

For examples, animals consume plants, fungi and other animals.0047

These consumers are called heterotrophs, and these are consumers of organic compounds.0052

Before we delve into the details of photosynthesis, it is important to understand overall what happens.0066

Here is the overall reaction for photosynthesis: six carbon dioxides plus six waters are used to form one molecule of glucose plus six oxygens.0072

CO2 is used, and oxygen is produced as a by-product.0086

Something else important to have here is energy.0092

This is an energy requiring the process, and that energy comes in the form of light, so light energy is used to fuel this process.0095

To survive, plants need to take in only water, minerals and CO2, and then, they can create the glucose that is used for cellular respiration.0108

Because energy must be input, this reaction is endergonic.0119

There are two processes in photosynthesis.0127

The first set of processes is called the light reactions or the light-dependent reactions.0132

The second are the light-independent reactions. These are also called the dark reactions.0142

The dark reactions or light-independent reactions do not directly require light.0157

However, the products of the light reactions are needed for the light-independent reactions to occur, so light is needed, but it is indirect.0162

Let's start out by talking about where photosynthesis takes place.0176

Here is a leaf, and on the right is a chloroplast, which is the organelle where photosynthesis takes place; and this was described in electron cell structure, but we are going to review it here.0182

Just starting out with the anatomy of the leaf, there is a waxy covering that protects the leaf and prevents water loss, and this is called the cuticle.0197

This cuticle layer is produced by a cell layer called the upper epidermis, and we will talk more about plant anatomy in the plants lecture.0208

What we are going to focus on now is layer of cells known as the mesophyll.0221

In the mesophyll layer, photosynthesis takes place.0231

Here, on the underside of a leaf, you will see openings, and these openings or pores are known as stomates.0241

Gas can enter and leave the cell through the stomate.0251

What is going to happen is CO2 is going to enter. Photosynthesis will take place, and oxygen can leave.0254

You notice that there is gaps between. This is called spongy mesophyll right here, and these cells in the spongy mesophyll are separated out.0261

And these air spaces that are created allow for the diffusion of gases.0272

The CO2 enters, can diffuse into the mesophyll cells where photosynthesis takes place.0278

The opening and closing of the stomates is controlled by what is called guard cells.0286

The guard cells surround these, and they can close it off, open up.0292

In addition to gases, something else that can be lost is water.0302

Stomates are a major source of water loss through a process called transpiration, so water loss through transpiration.0307

This is especially a problem in a climate that is hot and dry.0318

Here, we have what is called a vascular bundle, and the vascular tissues of the plant in here, there are two types- xylem and phloem.0321

The xylem is used to transport water and minerals from the roots up to the rest of the plants.0338

The phloem is used to transport the products of photosynthesis, glucose, to the rest of the cell.0348

Photosynthesis takes place in the leaves primarily, and the glucose can, then, be transported to other parts of the plants such as the roots.0356

This is leaf structure, and the mesophyll cells are the location of photosynthesis.0366

Within the cells where photosynthesis actually takes place is the chloroplast. This is just showing a chloroplast within a cell.0372

There is a fluid called stroma within a chloroplast, and the chloroplast are surrounded by a double membrane.0382

Like the mitochondria, this double membrane is taken as support for the endosymbiosis theory.0392

Recall the endosymbiosis theory says that organelles are a result of a symbiotic relationship between early prokaryotes.0399

In this case, an early prokaryote might have engulfed another photosynthetic prokaryote.0407

And eventually, that other prokaryote became dependent on the larger prokaryote and became part of it and is the chloroplast.0414

Like mitochondria, chloroplasts also have their own DNA. Again, that is also support for the endosymbiosis theory.0426

We have this double membrane. We have this fluid called stroma, and then, we have these stacks of discs called grana.0437

These discs, which are membranous, are called thylakoids, and we will talk in more detail about what happens, where each process takes place.0452

But one thing in general to remember is that the dark reactions take place in the stroma or the light-independent reactions, whereas the light reactions take place in the grana.0467

And the photosynthetic enzymes are embedded in the membranes of the thylakoid.0486

Cyanobacteria are also capable of undergoing photosynthesis, yet, they do not contain chloroplast.0494

Instead, photosynthesis takes place in infoldings of the cell membranes of these prokaryotes.0502

The infoldings in the cyanobacteria cell membrane are also called thylakoid membranes because they are the site of photosynthesis.0507

Alright, two parts of photosynthesis: light reactions and dark reactions.0517

We are going to focus first on the light reactions or the light-dependent reactions.0522

This is a stage of photosynthesis during which light energy is used to produce ATP.0528

ATP is needed for the dark reactions and that is when glucose is produced.0534

Light reactions produce the ATP. The ATP is, then, used in the dark reactions to actually form glucose.0541

To understand the light reactions, you need to understand a little bit about light and pigments.0552

Pigments are substances that absorb visible light, so pigments absorb visible light.0560

There are several pigments that we will talk about with photosynthesis, for example chlorophyll a, which participates in the light reactions,0577

also, chlorophyll b and another group of pigments called the carotenoids.0587

These are actually considered the accessory photosynthetic pigments. We will talk more about the functions of each of these.0598

We have chlorophyll a, chlorophyll b and carotenoids.0608

Different pigments absorb different wavelengths of light, and different wavelengths of light are different colors.0611

You notice here shorter wavelengths of light, for example 400nm appears violet.0617

Longer wavelength, here in the 500 range appears blue and then, so on, and then, red light has a much longer wavelength.0628

Several things can happen. A pigment can absorb light, or it can transmit light and reflect the light.0638

The reason plants appear green is that chlorophylls absorb violet, blue and red light, so they are absorbing all of this.0648

They transmit and reflect green light.0659

When you look at a plant, that plant, the pigments inside the chloroplast have absorbed this part of the spectrum.0662

And what you are seeing is what is reflected back by then, which is the green light.0672

These absorb blue, violet, red light, and they reflect and transmit green light.0676

Carotenoids actually absorb violet, blue and green light.0692

They are absorbing violet, blue and green light, and that leaves the red and orange part of the spectrum to be transmitted and reflected.0698

Red and orange are transmitted and reflected.0707

Sweet potatoes and carrots are very high in carotenoids.0712

And that is why when we look at them, they appear orange or reddish-orange or yellowish because they are reflecting yellow or orange light.0716

Something else to understand about light is that it behaves as both a wave and a particle.0731

Light has aspects to it that are like a wave and then, other aspects that are like a particle.0739

Photons are particles of light that contain a particular amount of energy, so a photon is a particle of light that contains a certain amount of energy.0756

The shorter the wavelength, the greater the energy in the photon, so violet light has a shorter wavelength than red light.0773

Therefore, violet light is going to contain more energy, and I am going to use light and light energy and photon interchangeably so you should be familiar with these terms.0783

OK, before we go on to talk about exactly what happens in the light reactions and how ATP is produced,0794

you need to understand how the pigments are arranged and how what is called photosystems are set up in the thylakoid membrane.0800

Recall that we have a chloroplast, and we have thylakoids stacked up into what is called a grana; and this is the location of the light reactions.0809

Now, looking at the close up, photosystems are located in the thylakoid membranes of the chloroplast. This is where the light reaction takes place.0823

These photosystems consist of two parts, a reaction center complex surrounded by several light-harvesting complexes.0833

This whole blue area is the reaction center complex, and it is surrounded by light-harvesting complexes, so here is one. Here is one.0843

Light-harvesting complex is just a group of pigment molecules.0860

Another name for light-harvesting complexes is antenna complexes, and the reason that these are called antenna complexes is because they pick up electromagnetic radiation.0867

They absorb electromagnetic radiation, and what light-harvesting complexes consist of is multiple types of pigments.0878

Different types of pigment molecules absorb different wavelengths of light more effectively0895

like I talked about the carotenoids absorbing certain wavelengths of light and reflecting others- chlorophyll a, chlorophyll b.0900

Different types of pigments absorb different light wavelengths.0908

Therefore, by having multiple different types of these pigment molecules, the antenna complexes can absorb light from a much wider range from the electromagnetic spectrum.0912

The job of a light-harvesting complex is to absorb light and - which we will talk about in a second - the absorption of that light excites these molecules.0927

These molecules become excited, and that energy is transferred to the reaction center.0940

Here in the reaction center are two...there is only one shown here. It is very schematic, but there are actually two chlorophyll a molecules.0946

And these chlorophyll molecules have special properties that allow them to actually donate an electron when the electrons are excited by this energy that has been transmitted.0957

And notice it says P680. I will talk in the next slide about what that means, but there are two different types of photosystems; and one, it will say P680 here, and the other is P700.0973

This is just a particular type of one of the two types of photosystems.0984

We have the reaction center complex. Light is exciting those pigment molecules.0989

The energy is being transmitted. Electrons are not transmitted.0993

It is just energy. One excites the next.0998

Next excites the next until it gets to this reaction center chlorophyll molecule.1000

And at that point, the excited electron from the reaction center chlorophyll molecule, two electrons are transferred to what is called the primary electron acceptor.1006

What has happened here is that light energy is turned into chemical energy through this transfer of electrons.1017

That is what the photosystem is doing. It is turning light energy into chemical energy.1031

Let's go ahead and look at a couple ways in which these electrons can be transferred because the first step here is the transfer of the electrons from P680 to this primary electron acceptor.1042

This is the redox situation transferring...that we are going to see a series of redox reactions.1055

This primary acceptor has the electrons, and then, we are going to see a series of redox reactions, and let's go ahead and look at this.1061

There are two ways in which electrons can be transferred in photosynthesis: linear or noncyclic photophosphorylation and cyclic photophosphorylation.1067

This is linear electron transfer, and you will see in this sketch compared with the next one that the electrons take a linear path from one to another or another, another and on.1079

This orange, or excuse me, the orange is the light.1089

The purple is the path the electrons are taking.1092

And you will what cyclic electrons transfer or cyclic photophosphorylation you are going to see the electrons actually flow in a circle.1097

First of all, what is photophosphorylation?1106

Well, photo means light. Phosphorylation means to add a phosphate group or phosphorus to a molecule, and what we want to end up here with is ATP.1109

We are using light energy to phosphorylate ADP, so ADP plus phosphate to make ATP, and light energy is used.1120

Light energy is harnessed for this reaction, so it is photophosphorylation, and here, it is with the noncyclic or linear electron transfer.1134

We already discussed the first step of this process, but I will recap it.1144

The first step is that light or photons hit the pigment.1148

Right here, which shown all of this, is the light-harvesting complex. Here is the reaction center.1156

Light hits the light-harvesting complex, and these photons are absorbed by the pigments here, and that excites the electrons in these pigments.1165

These electrons move to a higher energy state.1176

That energy, then, is transferred from pigment molecule to pigment molecule and then, eventually to the reaction center.1179

The reaction center here in photosystem II is called P680, and that is because this type of chlorophyll most effectively absorbs light energy of the wavelength of 680.1191

Over here, the other photosystems is photosystem II P700, and it most effectively absorbs light of a wavelength of 700.1205

Energy transferred from molecule to molecule in the light-harvesting complex eventually makes its way to transfer1219

the energy to these special chlorophyll molecules in the reaction center complex called P680.1225

When this molecule becomes excited, and its electrons are transferred to a higher energy level, the result is going to be the transfer of an electron.1233

And a total of two electrons are transferred by these chlorophyll molecules here to the primary electron acceptors, so this is the primary electron acceptor.1244

Light energy is being converted to chemical energy, so primary electron acceptor.1253

Those electrons are, then, going to be transferred through an electron transport chain.1261

And we talked in detail under the aerobic respiration lecture about what an electron transport chain is and how it works, and these electrons are transferred down in a series of redox reactions.1268

Let’s back up before we go any further with that and look at what is happening here.1280

P680 has lost two electrons. It needs to replace those electrons.1284

Where are those electrons going to come from?1289

Well, remember that water is required for photosynthesis, and what happens is the reaction center can perform photolysis.1290

Photolysis, if you look at the word water - excuse me - of photo for light and lysis for split or break, so this is the splitting of a molecule of water.1300

The reaction center, in addition to transmitting this energy around and donating these electrons to the primary electron acceptor, something else that happens in the reaction center is water is split.1314

Water is H2O. It is two hydrogens, one oxygen, and two hydrogens are composed of two electrons and two protons or two H+ molecules.1325

When water is split, you end up with two electrons, two protons and an oxygen.1345

Well, the oxygen is a by-product of photosynthesis, and it ends up just leaving the plant.1351

Notice that oxygen is written as 1/2 O2, and the reason is oxygen, as soon as it is split off, immediately combines with another oxygen molecule to form O2.1356

That is the state that it usually exists in instead of just saying "oh, we call it 1/2 O2 because it is usually floating around as O2".1367

OK, H2O, we have accounted for the oxygen. We have two electrons and two protons.1375

The two electrons are going to go ahead and be transferred to P680, and they will replace the electrons that P680 transferred to the primary acceptor.1382

P680 transferred two electrons. The reactions that are in a complex splits water, and two electrons from the water are used to replace electrons in P680.1398

In addition, this should actually be two protons are released.1408

The two electrons are transferred to P680. In addition, 1/2 O2 is released, and two protons are released.1415

OK, P680 had its electrons replaced. Now, let's look at what is happening here.1424

Electrons were transferred to the primary electron acceptor, and now, they are being passed along down the electron transport chain.1429

This electron transport chain is found in the thylakoid, and it consists of a series of protein complexes and carrier molecules and here where the first one, PQ is plastoquinone.1441

You do not have to memorize the whole name, but just so you know, this is plastoquinone. That is what that stands for- a cytochrome complex and plastocyanin.1457

These are the components of the electron transport chain, and recall with the electron transport chain in oxidative phosphorylation, that electrons are passed from one carrier molecule to the next.1467

And each electron carrier molecule is more electronegative than the one preceding it.1480

These electrons are going to a more electronegative molecule to even more to even more.1486

Because they are being passed to more electronegative molecules, the free energy is decreasing.1491

The free energy is decreasing as they go down here, and that release of energy can be used to generate a proton gradient.1497

Just as with oxidative phosphorylation, a proton gradient is created.1505

Remember that in photolysis, these protons were released.1511

Well, these protons are picked up by the electron transport chain and pumped.1515

They create a proton gradient in which there is a higher concentration of hydrogen ions in the lumen or in the space inside the thylakoid than there is out in the stroma.1521

This creates a proton. This electron transport chain creates a proton gradient between the thylakoid space and the stroma.1536

Recall in the chloroplast, we have the thylakoid stacked into grana and then, the stroma out here.1555

And that is going to end up being a gradient between these two areas, where there is a higher concentration in the thylakoid of protons and a lower one in the stroma.1565

Just like with oxidative phosphorylation, energy is released as these protons diffuse down their concentration gradient, and the energy is harnessed to phosphorylate ADP.1574

That is what we see here. ADP plus inorganic phosphate are combined to form ATP.1586

Remember the enzyme ATP synthase can couple hydrogen ions going down their concentration gradient with the syntheses of ATP because ATP synthase contains a proton channel.1593

This is another example of chemiosmosis, very similar to what we saw earlier that was happening in the mitochondria with oxidative phosphorylation.1605

The transfer of electrons down the electron transport chain to more electronegative molecules releases energy. The energy is used to pump protons.1618

Those protons form a gradient, and then, energy is harnessed as the protons flow down their concentration gradient through the channel ATP synthase, and ATP is formed.1630

Backing up for a second and realizing, the purpose of the light reactions in photosynthesis is the formation of ATP and NADPH.1642

Both of which are needed for the dark reactions, for the light-independent reactions.1650

With ATP and NADPH and CO2, it is possible to make glucose during the second part of photosynthesis.1655

Water is also needed for photosynthesis, and we see that here because those electrons are needed to replace the electrons transferred from P680; and it is a source of hydrogen ions for that gradient.1666

Aright, what is going on over here in photosystem I?1679

We focused on photosystem II, electron transport chain and ATP being made.1683

Meanwhile, while light is hitting photosystem II, it is also hitting photosystem I.1688

Again, light energy is absorbed by the pigment molecules, so these photons are absorbed.1696

The pigment molecule electrons become excited, and this energy is transferred from pigment molecule to pigment molecule in the light-harvesting complex; and then, it excites the electrons in P700.1702

Two electrons from these chlorophyll molecules are transferred to the primary electron acceptor in photosystem I so very similar to what happened in photosystem II so far.1716

Those electrons from the primary electron acceptor also go down in electron transport chain, so we have another electron transport chain here.1730

However, there is no proton gradient created here. There is no ATP created here.1738

Instead, the end point for these electrons is that they are donated to NADP+ to form NADPH.1744

NADP+ is an electron carrier similar to NAD or FAD that we talked about in earlier lectures.1753

And this is needed for the redox reaction in the Calvin cycle or in the light-independent reaction we will talk about in a few minutes.1764

Alright, the only thing that is missing here is how do we place the electrons that were transferred from P700?1774

Recall that in P680, it loses two electrons, but that is OK.1781

It splits water in photolysis, and those electrons are replaced. That does not happen here.1784

Instead, look where we stopped here.1790

Electrons transferred in photosystem I to the primary electron acceptor and down the ETC, and then, what happens to them?1793

Well, actually, those two electrons are donated to P700 to replace the electrons that were transferred to the primary electron acceptor.1801

This is a pretty complex cycle, but the important things to know is that there are two photosystems involve that light energy is used and collected by the antenna complex or the light-harvesting complex.1814

It is transferred to the reaction center complexes.1828

The chlorophyll molecules there donate electrons to the primary electron acceptors, and those electrons proceed down two electron transport chains.1835

The first electron transport chain uses chemiosmosis. It generates a proton gradient, and the energy from that is harnessed to make ATP.1846

The electron transport chain associated with photosystem I does not have a proton-motive force, a proton gradient.1856

It does not make ATP instead, it reduces NADP+ to NADPH.1867

We have these two things that are needed for the light-independent reactions.1874

The electrons in photosystem II are replaced by two electrons gained from splitting water, from photolysis.1878

The electrons in photosystem I that were donated to the primary acceptor are replaced by these electrons from photosystem II.1886

This is noncyclic photophosphorylation. The flow of electrons is linear.1897

In contrast, in cyclic photophosphorylation, there is only one photosystem involved, and this is photosystem I.1906

And you can already see that there is not a second photosystem here donating electrons linearly.1913

There is a single photosystem, and the electrons go in a cyclical pattern.1919

The first step is the same. Sunlight is used as the energy source.1926

Those photons excite the electrons in the light harvesting complex, in the antenna complex.1934

That energy is transferred from pigment molecule to pigment molecule and then, eventually to the new pigment molecule in the reaction center complex, the pigment molecules.1941

Same as before, two electrons are, then, donated to the primary electron acceptor.1956

What happens next is those two electrons are passed along the ferredoxin, a carrier of electrons.1963

And you recall in photosystem I in the last slide, this was the first electron carrier that photosystem I donated to in noncyclic photophosphorylation as well.1971

The second step is different, however.1982

The next step is ferredoxin donates those electrons through a redox reaction to cytochrome complex, then, to plastocyanin.1985

Then, those electrons go back and replace the electrons lost from P700 in the first place, so it goes in a cycle.1995

This is different than what we saw in the previous slide with noncyclic phosphorylation because there is no NADPH formed, and the flow of electrons is circular rather than linear.2008

However, there is still the production of ATP.2024

Some photosynthetic bacteria use this system only. Others use both.2032

It is possible that this is actually an older system than the linear electron flow that we talked about.2039

But either way, the cell ends up with the ATP that it needs in order for the light-independent reactions to occur and glucose to be produced.2046

There is no NADPH. However, there is a proton gradient, so check.2057

There is a proton gradient produced, and through chemiosmosis, ATP is produced- so much simpler system than the previous one.2062

OK, the light-independent reactions are the step of photosynthesis in which glucose is formed, and this is called - this light-independent reaction we are focusing on - the Calvin cycle.2075

And during the Calvin cycle, a sugar called glyceraldehyde-3-phosphate is formed, so glucose is not directly formed by the Calvin cycle.2087

Instead, G3P or PGAL...this is all the same sugar, glyceraldehyde-3-phosphate, PGAL and G3P are all the same, and 2 PGAL molecules can be used to form glucose.2094

Even though in photosynthesis, the Calvin cycle does not directly form glucose, it forms a sugar that can be used to make glucose.2110

Let's look at what is happening.2120

CO2 is input in this cycle, and it is fixed.2122

When we talk about being fixed, that a carbon molecule is fixed, we mean that it is being incorporated into an organic molecule, into an organic compound.2127

We start out with ribulose bisphosphate or RuBP, which is a 5-carbon molecule.2137

A CO2 is added, and this is catalyzed by the enzyme RuBisCO to form the six, a very unstable intermediate molecule.2142

It is six carbons. It is unstable.2152

It quickly breaks down into two 3-phosphoglycerate molecules.2154

Now, you will notice that I wrote CO2 x 3 here.2160

The CO2s enter one at a time, but it is good to look at this cycle in terms of three turns of the cycle2164

because it would take a total of three CO2s to get enough new carbon in there to generate the equivalent of one PGAL.2170

After each turn, a PGAL comes out, but you have only added one carbon.2179

So, if you ask how many CO2s would you have to put in to really have enough carbon to create PGAL? It is three turns.2183

And it would require six turns of the cycle to generate glucose because you need two PGALs, six carbons total, for a glucose.2191

In this first step, RuBisCO fixed this carbon into ribulose bisphosphate to form an unstable intermediate, and if this happens three times, we are going to get three of those.2202

This 3-carbon molecule splits into two, so that is 3 x 2, that is 6. Therefore, it is three phosphoglycerate.2214

Here is where the ATP comes in.2223

Remember that the light in the light-dependent reactions, the light reactions that we just talked about, generate ATP, and that ATP is used to phosphorylate 3-phosphoglycerate.2226

This is the phosphate source to form 1,3-bisphosphoglycerate.2240

The next one we have is a redox reaction.2246

Again, from the light reactions, we got NADPH. This NADPH is oxidized and 1,3-bisphosphoglycerate is reduced.2248

In addition, one of the phosphate groups is removed.2262

The phosphate is lost from the substrate molecule, and it is reduced to form glyceraldehyde-3-phosphate or PGAL.2267

After three turns of the cycle, we would end up with six, six, six PGALS. One of these leaves the cycle.2278

OK, we are left with five PGALs. One leaves the cycle, and this one that leaves can be used to form glucose.2289

It can be used as a backbone for other molecules. It can be used to form other organic molecules.2298

This one is gone. That leaves five.2306

Now, let's keep track of the carbons. It is always important in cellular respiration to keep track of the carbons.2309

I have three carbons in this molecule. PGAL is a 3-carbon molecule, and one left the cycle.2316

I have five left. 5 x 3 is 15 carbons.2323

From those 15 carbons, you can get three RuBPs because RuBP is a 5-carbon molecule. 5 x 3 is 15 carbons.2328

By rearranging and phosphorylating these, we get RuBP back, and this phosphorylation, you need a source of phosphate; and the source again, is ATP.2342

Here, we see ATP, ATP and NADPH being used, and those came from the light reaction.2352

Even though the sun does not have to provide energy directly into the Calvin cycle, that energy was needed to generate ATP, which is being used by the Calvin cycle.2358

In order to get one molecule of glucose, what did we have to use?2373

Well, to get one molecule of PGAL, we had to use nine ATPs and six NADPHs per PGAL.2377

Remember though, it takes two PGALs to have enough carbon to make a glucose.2389

Therefore, we have to use eighteen ATPS and six NADPHs per glucose molecule created by photosynthesis.2394

This pathway for the Calvin cycle is called the C3 pathway, and it is used by C3 plants.2407

And the reason is the first true metabolic intermediate created is 3-phosphoglycerate, which is a 3-carbon molecule.2414

This is so unstable and quickly splits. We do not even count that one.2422

We just look at this and say "OK, 3-carbon molecule". This is the C3 pathway.2426

There is another pathway that can occur that is called photorespiration.2433

And it has to do with the fact that that first enzyme I mentioned that catalyzes the first step of the reaction, RuBisCO, RuBisCO can also bind to oxygen.2439

Remember that RuBisCO fixes carbon. It fixes CO2 to form an organic molecule using RuBP plus CO2 to form 3-phosphoglycerate.2453

We get RuBP plus CO2 to get that 3-carbon molecule, 3-phosphoglycerate.2468

That is what we want to happen- photosynthesis. The Calvin cycle occurs.2479

PGAL will be produced. Glucose will be produced.2484

However, RuBisCO also binds oxygen.2486

Normally, under typical conditions, this may not be a problem, but under certain conditions, it can create a problem and in fact, stunt the plant growth.2501

The reason is, if oxygen is fixed then, the plant is not going to be performing photosynthesis.2510

This RuBisCO is, instead, binding O2.2518

It is going to divert the plant, at least, partly from photosynthesis, and instead, what is going to happen is the process called photorespiration.2521

This is most likely to occur under hot, dry conditions, and the reason is that hot, dry conditions leads to decreased CO2 concentration. Why is this?2531

Well, remember that the stomates allow for gas to enter and leave the plant.2545

The stomates open. CO2 enters.2551

Photosynthesis occurs. Oxygen is created.2556

Oxygen leaves. The only problem is a lot of water is lost in the stomates.2559

Under hot, dry conditions, the stomates will close to conserve water.2565

The result is that the CO2 level drops, and because RuBisCO has an affinity for oxygen, when CO2 is low,2571

there is a relatively higher concentration of oxygen, lower concentration of CO2. It grabs on to that oxygen.2578

OK, what happens? Instead of fixing CO2, it fixes oxygen, and what results in photorespiration is oxygen is fixed; and it forms a 3-carbon compound.2586

What ends up happening in that compound? Well, it exits the chloroplast.2604

The compound is taken up by peroxisomes. Inside the peroxisomes, it is broken down, and CO2 is released.2610

Seems like a waste because you will notice no ATP was produced.2624

No NADPH is produced. No glucose was produced2631

The point of photosynthesis is to form glucose.2638

It is not like normal photosynthesis. You are not getting glucose out.2644

It is called photorespiration, so it is a type of respiration; but in regular cellular respiration, when we talked about aerobic and anaerobic respiration, ATP was produced.2649

This is not really doing anything useful, and in fact, the plant's growth get stunted.2659

Examples of C3 plants are plants like rice and wheat, and you might ask “well, why does the plant even do this?”.2665

Well, nobody is really sure, but it is possible that this is just an evolutionary left over.2671

It is a remnant from evolution because long ago, evolutionarily, there was a lower oxygen level in the atmosphere2676

So, it is possible that RuBisCO binding oxygen was not a problem because the conditions were higher in CO2.2688

And even though there was that capability, it never was a positive or a negative. It just did not really have a big effect.2697

Under current conditions, when the oxygen level was higher, it becomes a problem because, then, RuBisCO does bind the oxygen. Photorespiration does occur.2703

That is one theory on why this may occur.2716

What do plants in hot, dry conditions do so that they can continue to grow and thrive and not have this photorespiration diverting the process of photosynthesis?2720

Well, there is a couple of adaptations.2731

There are certain group of plants called C4 plants, and these are plants found in hot, dry environments; and they have an altered leaf anatomy and a slightly different pathway for photosynthesis.2733

Let's first look at the leaf anatomy.2748

A couple things, we still have that upper epidermis and the mesophyll layer where photosynthesis takes place.2750

There is stomates that we talked about before, and here is the vascular bundle.2759

Now, you will notice this group of cells around the vascular bundle, and these are called bundle-sheath cells.2765

In C4 plants, the light reactions take place in the mesophyll cells, and the Calvin cycle, the dark reactions or light-independent reactions, take place in the bundle-sheath cells.2774

These two processes are separated out.2793

Let's look at what happens first in the mesophyll cell.2797

The light reactions are taking place here, and, as usual, ATP is being produced; and something else happens in these mesophyll cells. CO2 is fixed.2803

In C3 plants, the CO2 fixation initially occurs in the Calvin cycle.2818

That is where it is first integrated into an organic compound, but the problem is, the enzyme that is doing that fixing RuBisCO, can bind to oxygen.2823

The CO2 comes in, and instead of just letting it go into these bundle-sheath cells where the RuBisCO is waiting, it goes into the mesophyll cells.2833

And there, the carbon is fixed into an organic compound.2846

The good thing about this is that the enzyme that catalyzes the fixation of CO2 in the mesophyll cell2851

does not bind to oxygen and has a very high affinity for CO2, even higher than RuBisCO does.2859

What you can think of this as is that the mesophyll cells are just grabbing up the CO2 and fixing it.2866

They fix it to form an organic compound oxaloacetate that you are probably familiar with from the citric acid cycle and then, used to form malate.2876

This malate is, then, transported into the bundle-sheath cell, where it is broken down into pyruvate, and CO2 is released.2886

Notice that these bundle-sheath cells are sequestered. They are more towards the center of the leaf.2896

What has happened is a microenvironment is created within these bundle-sheath cells, where there is a high concentration of CO2.2902

As long as there is a high concentration of CO2, RuBisCO is fine because it will tend to bind the CO2, and photosynthesis will occur.2910

Where problems occur, is when there is a high concentration of oxygen.2919

If you have these cells sitting over here, and there is oxygen, then, the RuBisCO might bind that.2923

Instead, the cell depends on an enzyme that binds only to CO2 instead of O2 to immediately fix the CO22930

and then, shunt it into these sequestered cells, where there is higher CO2 levels, where a RuBisCO can safely perform the Calvin cycle.2937

There is this separation between the processes. The light processes take place here.2950

The Calvin cycle takes place in the bundle-sheath cell, and initial fixation of the carbon takes place in the mesophyll cell although it is exported out into the other cell.2956

Why is this called C4? Well, the reason is oxaloacetate is a 4-carbon molecule.2970

Remember in C3 plants with the Calvin cycle, that initial intermediate of the Calvin cycle is a 3-carbon molecule, so we call that C3.2976

Here, carbon is not being fixed initially in the Calvin cycle. It is being fixed in this process in the mesophyll cell.2988

And initially, we end up with oxaloacetate, a 4-carbon molecule, so these are called C4 plants; and this export of malate occurs through plasmodesmata.2995

Remember we talked about these openings between plant cells in an earlier lecture on cell structure.3005

The second method by which plants can avoid photorespiration is via the CAM pathway or Crassulacean acid metabolism- CAM.3020

CAM plants are plants like cacti. They are succulents that live in hot, dry dessert environments.3037

And in such an environment, these plants really need to keep their stomates closed during the day, or there will be too much water loss. There is a problem with that though.3043

Normally, the stomates are open during the day. That way, CO2 can come into the plant.3054

And it is ready for the Calvin cycle at the same time of day when sunlight is available because the Calvin cycle needs the ATP and NADPH from the light reactions.3062

If the sun is out, light reactions are occurring. The stomates are open.3073

CO2 comes in. The Calvin cycle is occurring.3077

That ATP is being used. The CO2 is being used.3080

Glucose is produced. However, CAM plants have developed a way to pick up the CO2 at night and hold on to it until the day time.3084

The way it works with these plants is they keep their stomates closed during the day. At night, the stomates open up, and CO2 enters the cell.3097

There has got to be a way, though, for them to save that CO2 until morning when the light reactions can occur.3110

And the way they do that is by fixing the CO2 into an organic compound called malic acid.3116

CAM plants store carbon. They store the CO2 in the form of organic acids, and this is all occurring in the same cell.3124

There is not the separation in the two different cell types.3143

The light and dark reactions can all occur in the same cell type. It is different than what we saw in the C4 plants.3146

OK, at night, the stomates are open. CO2 comes in.3153

It is converted to malic acid.3158

In the morning, the stomate is closed. No CO2 is coming in, but there is light energy during the day.3160

And the light reactions are forming ATP and NADPH, and now, the Calvin cycle can occur because the ATP and NADPH is available.3168

What happens during the day is the CO2 is released and then, fixed as part of the Calvin cycle during the day when ATP and NADPH are available.3183

In the end, whether it is a C3 pathway, a C4 plant or a CAM plant, the same thing has happened with photosynthesis.3198

Water, CO2 and light energy were used to produce glucose.3209

In C4 and CAM plants, we saw some steps prior to the Calvin cycle, different thing were done with the CO2.3221

But in the end, it is all the same, and the plant is going to end up with PGAL molecules and thus, glucose.3228

That glucose can be used in cellular respiration to form ATP, so the energy in the glucose can be released. ATP can be used, and that is going to fuel the cellular processes.3241

This glucose produced or the PGAL can also be used as a carbon skeleton for other organic compounds in the plant.3257

Excess sugar made by the plant via photosynthesis is stored as starch.3265

Alright, let's go ahead and review what has been covered today.3272

In example one: although the Calvin cycle is called a light-independent reaction, in the absence of light the cycle cannot occur in plants. Why not?3276

Well, maybe it could occur for a little while, but it would quickly stop; and the reason is that the Calvin cycle requires ATP and NADPH, and these are produced via the light reactions.3285

Therefore, if you stick a plant in the dark, and you give it a plenty of CO2, OK, there is plenty of CO2, there is plenty of water, the plant dies.3314

Well, it is because it does not have the energy source or the NADPH needed for the Calvin cycle to occur, so we will not be reproducing glucose.3326

Even though it is not directly dependent on light, it is dependent on the products of the light reactions.3339

Below is the drawing of the leaf structure in a C4 plant.3350

Label the following: stomate, vascular bundle, cells that are the site of fixation of CO2 resulting in the formation of the organic acid malate, site where the Calvin cycle occurs.3356

Alright, remember that C4 plants have a different anatomy.3373

This is also called kranz anatomy, and it allows the plant to minimize the photorespiration; and this is found in plants in hot, dry environments.3377

So, stomate right here, this is a stomate. These are pores that allow for gas to enter and leave the leaf.3388

Vascular bundle, that is the structure right here.3399

The vascular bundle contains the vascular tissue xylem and phloem that carries water, minerals and glucose - water and minerals for the xylem and nutrients for the phloem - throughout the plant.3404

Now, were talking about the C4 plant, so in C4 plants, carbon dioxide enters the stomates, enters the mesophyll cells and is initially fixed to form the organic acid malate or malic acid.3421

These cells are the mesophyll cells, and that is where CO2 is going to initially fixed.3438

And then, that organic acid can be transported into the bundle-sheath cells released, forming pyruvate and CO2, and the site where the Calvin cycle occurs is the bundle-sheath cells.3447

The RuBisCO is sequestered in these bundle-sheath cells in the interior of the leaf, where there is not going to be so much risk of binding oxygen and photorespiration occurring.3468

The mesophyll is the site of the fixation of CO2 initially fixed, and then, it is released and fixed again in bundle-sheath cells.3480

The malate is formed in the mesophyll cells, and the bundle-sheath cells are the site of the Calvin cycle.3494

Stomate, vascular bundle, mesophyll cells, where CO2 is fixed to form the organic acid malic acid and then, bundle-sheath cells where the Calvin cycle takes place.3502

Example three: list three major differences between photosynthesis and photorespiration.3516

Alright, photosynthesis is the process by which CO2 is fixed - so photosynthesis - and glucose is produced.3525

Oxygen is a by-product, so oxygen is released.3558

In earlier steps of photosynthesis, ATP in the light reactions, they are made, but they are also used; so they are both made and used.3564

Now, photorespiration, photorespiration is a process that occurs when there is a low CO2 concentration.3578

That occurs usually under hot, dry conditions, and it is not good for the plant, stunts the plant growth, and if we look at the differences, we will see why.3591

Instead of CO2 being fixed and glucose being produced, oxygen is fixed.3599

CO2 is produced. No glucose is made, and there is no ATP or NADPH made.3607

Photorespiration is really just a dead end process, whereas photosynthesis results in the formation of glucose, which is necessary for the plant to live.3630

Example four: most plants have their stomates open during the day in order to obtain carbon dioxide when the sunlight is available for the light reactions.3644

CAM plants have stomates open at night and close during the day yet, they are still able to undergo photosynthesis? How is this possible?3654

Alright, normally, stomates are open during the day.3664

The CO2 enters the cell, and therefore, during the day when there is sunlight available, the light reactions occur.3668

ATP and NADPH are produced, and then, that along with the CO2, is used for the Calvin cycle.3676

CAM plants have stomates closed during the day.3684

When the sunlight is available, and ATP and NADPH are being made, the stomates are shut, and the plant cannot get CO2, how does it work?3688

Well, recall that CAM plants obtain CO2 at night and store it in the vacuoles as malic acid.3698

They pick up the CO2 at night, fix it into organic acids and then, store it in vacuoles.3718

In the morning, the CO2 is released from the organic compound and used for the Calvin cycle at a time of day when the light reactions are occurring and ATP and NADPH are available.3727

That concludes this lecture on photosynthesis at Educator.com.3753

Thanks for visiting.3758