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Bryan Cardella

Bryan Cardella

Viruses

Slide Duration:

Table of Contents

I. Introduction to Biology
Scientific Method

26m 23s

Intro
0:00
Origins of the Scientific Method
0:04
Steps of the Scientific Method
3:08
Observe
3:21
Ask a Question
4:00
State a Hypothesis
4:08
Obtain Data (Experiment)
4:25
Interpret Data (Result)
5:01
Analysis (Form Conclusions)
5:38
Scientific Method in Action
6:16
Control vs. Experimental Groups
7:24
Independent vs. Dependent Variables
9:51
Other Factors Remain Constant
11:03
Scientific Method Example
13:58
Scientific Method Illustration
17:35
More on the Scientific Method
22:16
Experiments Need to Duplicate
24:07
Peer Review
24:46
New Discoveries
25:23
Molecular Basis of Biology

46m 22s

Intro
0:00
Building Blocks of Matter
0:06
Matter
0:32
Mass
1:10
Atom
1:48
Ions
5:50
Bonds
8:29
Molecules
9:55
Ionic Bonds
9:57
Covalent Bonds
11:10
Water
12:30
Organic Compounds
17:48
Carbohydrates
18:04
Lipids
19:43
Proteins
20:42
Nucleic Acids
22:21
Carbohydrates
22:54
Sugars
22:56
Functions
23:42
Molecular Representation Formula
26:34
Examples
27:15
Lipids
28:44
Fats
28:46
Triglycerides
29:04
Functions
32:10
Steroids
33:43
Saturated Fats
34:18
Unsaturated Fats
36:08
Proteins
37:26
Amino Acids
37:58
3D Structure Relates to Their Function
38:54
Structural Proteins vs Globular Proteins
39:41
Functions
40:41
Nucleic Acids
42:53
Nucleotides
43:04
DNA and RNA
44:34
Functions
45:07
II. Cells: Structure & Function
Cells: Parts & Characteristics

1h 12m 12s

Intro
0:00
Microscopes
0:06
Anton Van Leeuwenhoek
0:58
Robert Hooke
1:36
Matthias Schleiden
2:52
Theodor Schwann
3:19
Electron Microscopes
4:16
SEM and TEM
4:54
The Cell Theory
5:21
3 Tenets
5:24
All Organisms Are Composed of One Or More Cells
5:46
The Cell is the Basic Unit of Structure and Function for Organisms
6:01
All Cells Comes from Preexisting Cells
6:34
The Characteristics of Life
8:09
Display Organization
8:18
Grow and Develop
9:12
Reproduce
9:33
Respond to Stimuli
9:55
Maintain Homeostasis
10:23
Can Evolve
11:37
Prokaryote vs. Eukaryote
11:53
Prokaryote
12:13
Eukaryote
14:00
Cell Parts
16:53
Plasma Membrane
18:27
Cell Membrane
18:29
Protective and Regulatory
18:52
Semi-Permeable
19:18
Polar Heads with Non-Polar Tails
20:52
Proteins are Imbedded in the Layer
22:46
Nucleus
25:53
Contains the DNA in Nuclear Envelope
26:31
Brain on the Cell
28:12
Nucleolus
28:26
Ribosome
29:02
Protein Synthesis Sites
29:25
Made of RNA and Protein
29:29
Found in Cytoplasm
30:24
Endoplasmic Reticulum
31:49
Adjacent to Nucleus
32:07
Site of Numerous Chemical Reactions
32:37
Rough
32:56
Smooth
33:48
Golgi Apparatus
34:54
Flattened Membranous Sacs
35:10
Function
35:45
Cell Parts Review
37:06
Mitochondrion
39:45
Mitochondria
39:50
Membrane-Bound Organelles
40:07
Outer Double Membrane
40:57
Produces Energy-Storing Molecules
41:46
Chloroplast
43:45
In Plant Cells
43:47
Membrane-Bound Organelles with Their Own DNA and Ribosomes
44:20
Thylakoids
44:59
Produces Sugars Through Photosynthesis
45:46
Vacuoles/ Vesicles
46:44
Vacuoles
47:03
Vesicles
47:59
Lysosome
50:21
Membranous Sac for Breakdown of Molecules
50:34
Contains Digestive Enzymes
51:55
Centrioles
53:15
Found in Pairs
53:18
Made of Cylindrical Ring of Microtubules
53:22
Contained Within Centrosomes
53:51
Functions as Anchors for Spindle Apparatus in Cell Division
54:06
Spindle Apparatus
55:27
Cytoskeleton
55:55
Forms Framework or Scaffolding for Cell
56:05
Provides Network of Protein Fibers for Travel
56:24
Made of Microtubules, Microfilaments, and Intermediate Filaments
57:18
Cilia
59:21
Cilium
59:27
Made of Ring of Microtubules
1:00:00
How They Move
1:00:35
Flagellum
1:02:42
Flagella
1:02:51
Long, Tail-Like Projection from a Cell
1:02:59
How They Move
1:03:27
Cell Wall
1:05:21
Outside of Plasma Membrane
1:05:25
Extra Protection and Rigidity for a Cell
1:05:52
In Plants
1:07:19
In Bacteria
1:07:25
In Fungi
1:07:41
Cytoplasm
1:08:07
Fluid-Filled Region of a Cell
1:08:24
Sight for Majority of the Cellular Reactions
1:08:47
Cytosol
1:09:29
Animal Cell vs. Plant Cell
1:09:10
Cellular Transport

32m 1s

Intro
0:00
Passive Transport
0:05
Movement of Substances in Nature Without the Input of Energy
0:14
High Concentration to Low Concentration
0:36
Opposite of Active Transport
1:41
No Net Movement
3:20
Diffusion
3:55
Definition of Diffusion
3:58
Examples
4:07
Facilitated Diffusion
7:32
Definition of Facilitated Diffusion
7:49
Osmosis
9:34
Definition of Osmosis
9:42
Examples
10:50
Concentration Gradient
15:55
Definition of Concentration Gradient
16:01
Relative Concentrations
17:32
Hypertonic Solution
17:48
Hypotonic Solution
20:07
Isotonic Solution
21:27
Active Transport
22:49
Movement of Molecules Across a Membrane with the Use Energy
22:51
Example
23:30
Endocytosis
25:53
Wrapping Around of Part of the Plasma
26:13
Examples
26:26
Phagocytosis
28:54
Pinocytosis
29:02
Exocytosis
29:40
Releasing Material From Inside of a Cell
29:43
Opposite of Endocytosis
29:50
Cellular Energy, Part I

52m 11s

Intro
0:00
Energy Facts
0:05
Law of Thermodynamics
0:16
Potential Energy
2:27
Kinetic Energy
2:50
Chemical Energy
3:01
Mechanical Energy
3:20
Solar Energy
3:41
ATP Structure
4:07
Adenosine Triphosphate
4:12
Common Energy Source
4:25
ATP Function
6:13
How It Works
7:18
What It Is Used For
7:43
GTP
9:36
ATP Cycle
10:35
ATP Formation
10:49
ATP Use
12:12
Enzyme Basics
13:51
Catalysts
13:59
Protein-Based
14:39
Reaction Occurs
14:51
Enzyme Structure
19:14
Active Site
19:23
Induced Fit
20:15
Enzyme Function
21:22
What Enzymes Help With
21:31
Inhibition
21:57
Ideal Environment to Function Properly
22:57
Enzyme Examples
25:26
Amylase
25:34
Catalase
26:03
DNA Polymerase
26:21
Rubisco
27:06
Photosynthesis
28:19
Process To Make Glucose
28:27
Photoauthotrophs
28:34
Endergonic
30:08
Reaction
30:22
Chloroplast Structure
31:55
Photosynthesis Factories Found in Plant Cells
32:26
Thylakoids
32:29
Stroma
33:18
Chloroplast Micrograph
34:14
Photosystems
34:46
Thylakoid Membranes Are Filled with These Reaction Centers
34:58
Photosystem II and Photosystem I
35:47
Light Reactions
37:09
Light-Dependent Reactions
37:24
Step 1
37:35
Step 2
38:31
Step 3
39:33
Step 4
40:33
Step 5
40:51
Step 6
41:30
Dark Reactions
43:15
Light-Independent Reactions or Calvin Cycle
43:19
Calvin Cycle
44:54
Cellular Energy, Part II

40m 50s

Intro
0:00
Aerobic Respiration
0:05
Process of Breaking Down Carbohydrates to Make ATP
0:45
Glycolysis
1:44
Krebs Cycle
1:48
Oxidative Phosphorylation
2:06
Produces About 36 ATP
2:24
Glycolysis
3:35
Breakdown of Sugar Into Pyruvates
4:16
Occurs in the Cytoplasm
4:30
Krebs Cycle
11:40
Citric Acid Cycle
11:42
Acetyl-CoA
12:04
How Pyruvate Gets Modified into acetyl-CoA
12:35
Oxidative Phosphorylation
22:45
Anaerobic Respiration
29:44
Lactic Acid Fermentation
31:06
Alcohol Fermentation
31:51
Produces Only the ATP From Glycolysis
32:09
Aerobic Respiration vs. Photosynthesis
36:43
Cell Division

1h 9m 12s

Intro
0:00
Purposes of Cell Division
0:05
Growth and Development
0:17
Tissue Regeneration
0:51
Reproduction
1:51
Cell Size Limitations
4:01
Surface-to-Volume Ratio
5:33
Genome-to-Volume Ratio
10:29
The Cell Cycle
12:20
Interphase
13:23
Mitosis
14:08
Cytokinesis
14:21
Chromosome Structure
16:08
Sister Chromatids
19:00
Centromere
19:22
Chromatin
19:48
Interphase
21:38
Growth Phase #1
22:25
Synthesis of DNA
23:09
Growth Phase #2
23:52
Mitosis
25:13
4 Main Phases
25:21
Purpose of Mitosis
26:40
Prophase
28:46
Condense DNA
28:56
Nuclear Envelope Breaks Down
29:44
Nucleolus Disappears
30:04
Centriole Pairs Move to Poles
30:31
Spindle Apparatus Forms
31:22
Metaphase
32:36
Chromosomes Line Up Along Equator
32:43
Metaphase Plate
33:29
Anaphase
34:21
Sister Chromatids are Separated
34:26
Sister Chromatids Migrate Towards Poles
36:59
Telophase
37:17
Chromatids Become De-Condensed
37:31
Nuclear Envelope Reforms
37:59
Nucleoli Reappears
38:22
Spindle Apparatus Breaks Down
38:32
Cytokinesis
39:01
In Animal Cells
39:31
In Plant Cells
40:38
Cancer in Relation to Mitosis
41:59
Cancer Can Occur in Multicellular Organism
42:31
Particular Genes Control the Pace
43:11
Benign vs. Malignant
45:13
Metastasis
46:45
Natural Killer Cells
47:33
Meiosis
48:17
Produces 4 Cells with Half the Number of Chromosomes
49:02
Produces Genetically Unique Daughter Cells
51:56
Meiosis I
52:39
Prophase I
53:14
Metaphase I
57:44
Anaphase I
59:10
Telophase I
1:00:00
Meiosis II
1:01:04
Prophase II
1:01:08
Metaphase II
1:01:32
Anaphase II
1:02:08
Telophase II
1:02:43
Meiosis Overview
1:03:39
Products of Meiosis
1:06:00
Gametes
1:06:10
Sperm and Egg
1:06:17
Different Process for Spermatogenesis vs. Oogenesis
1:06:27
III. From DNA to Protein
DNA

51m 42s

Intro
0:00
DNA: Its Role and Characteristics
0:05
Deoxyribonucleic Acid
0:17
Double Helix
1:28
Nucleotides
2:31
Anti-parallel
2:46
Self-Replicating
3:36
Codons, Genes, Chromosomes
3:56
DNA: The Discovery
5:13
DNA First Mentioned
5:50
Bacterial Transformation with DNA
6:32
Base Pairing Rule
8:06
DNA is Hereditary Material
9:44
X-Ray Crystallography Images
10:46
DNA Structure
11:49
Nucleotides
12:54
The Double Helix
16:34
Hydrogen Bonding
16:40
Backbone of Phosphates and Sugars
19:25
Strands are Anti-Parallel
19:37
Nitrogenous Bases
20:52
Purines
21:38
Pyrimidines
22:46
DNA Replication Overview
24:33
DNA Must Duplicate Every Time a Cell is Going to Divide
24:34
Semiconservative Replication
24:49
How Does it Occur?
27:34
DNA Replication Steps
28:39
DNA Helicase Unzips Double Stranded DNA
28:49
RNA Primer is Laid Down
29:10
DNA Polymerase Attaches Complementary Bases in Continuous Manner
30:07
DNA Polymerase Attaches Complementary Bases in Fragments
31:06
DNA Polymerase Replaces RNA Primers
31:22
DNA Ligase Connects Fragments Together
31:44
DNA Replication Illustration
32:25
'Junk' DNA
45:02
Only 2% of the Human Genome Codes for Protein
45:11
What Does Junk DNA Mean to Us?
46:52
DNA Technology Uses These Sequences
49:20
RNA

51m 59s

Intro
0:00
The Central Dogma
0:04
Transcription
0:57
Translation
1:11
RNA: Its Role and Characteristics
2:02
Ribonucleic Acid
2:06
How It Is Different From DNA
2:59
DNA and RNA Differences
5:00
Types of RNA
6:01
Messenger RNA
6:15
Ribosomal RNA
6:49
Transfer RNA
7:52
Others
8:54
Transcription
9:26
Process in Which RNA is Made From a Gene in DNA
9:30
How It's Done
9:55
Summary of Steps
10:35
Transcription Steps
11:54
Initiation
11:57
Elongation
15:57
Termination
18:10
RNA Processing
21:35
Pre-mRNA
21:37
Modifications
21:53
Translation
27:01
Process in Which mRNA Binds with a Ribosome and tRNA and rRNA Assist
27:03
Summary of Steps
28:39
Translation the mRNA Code
28:59
Every Codon in mRNA Gets Translated to an Amino Acid
29:14
Chart Providing the Resulting Translation
29:19
Translation Steps
32:20
Initiation
32:23
Elongation
35:31
Termination
38:43
Mutations
40:22
Code in DNA is Subject to Change
41:00
Why Mutations Happen
41:23
Point Mutation
43:16
Insertion / Deletion
47:58
Duplications
50:03
Genetics, Part I

1h 15m 17s

Intro
0:00
Gregor Mendel
0:05
Father of Genetics
0:39
Experimented with Crossing Peas
1:02
Discovered Consistent Patterns
2:37
Mendel's Laws of Genetics
3:10
Law of Segregation
3:20
Law of Independent Assortment
5:07
Genetics Vocabulary #1
6:28
Gene
6:42
Allele
7:18
Homozygous
8:25
Heterozygous
9:39
Genotype
10:15
Phenotype
11:01
Hybrid
11:53
Pure Breeding
12:28
Generation Vocabulary
13:03
Parental Generation
13:25
1st Filial
13:58
2nd Filial
14:06
Punnett Squares
15:07
Monohybrid Cross
18:52
Mating Pure-Breeding Peas in the P Generation
19:09
F1 Cross
21:31
Dihybrid Cross Introduction
23:42
Traced Inheritance of 2 Genes in Pea Plants
23:50
Dihybrid Cross Example
26:07
Phenotypic Ratio
31:34
Incomplete Dominance
32:02
Blended Inheritance
32:27
Example
32:35
Epistasis
35:05
Occurs When a Gene Has the Ability to Completely Cancel Out the Expression of Another Gene
35:10
Example
35:30
Multiple Alleles
40:12
More Than Two Forms of Alleles
40:23
Example
41:06
Polygenic Inheritance
46:50
Many Traits Get Phenotype From the Inheritance of Numerous Genes
46:58
Example
47:26
Test Cross
51:53
In Cases of Complete Dominance
52:03
Test Cross Demonstrates Which Genotype They Have
52:52
Sex-Linked Traits
53:56
Autosomes
54:21
Sex Chromosomes
54:57
Genetic Disorders
59:31
Autosomal Recessive
1:00:00
Autosomal Dominant
1:06:17
Sex-Linked Recessive
1:09:19
Sex-Linked Dominant
1:13:41
Genetics, Part II

49m 57s

Intro
0:00
Karotyping
0:04
Process to Check Chromosomes for Abnormal Characteristics
0:08
Done with Cells From a Fetus
0:58
Amniocentesis
1:02
Normal Karotype
2:43
Abnormal Karotype
4:20
Nondisjunction
5:14
Failure of Chromosomes to Properly Separate During Meiosis
5:16
Nondisjunction
5:45
Typically Causes Chromosomal Disorders Upon Fertilization
6:33
Chromosomal Disorders
10:52
Autosome Disorders
11:01
Sex Chromosome Disorders
14:06
Pedigrees
20:29
Visual Depiction of an Inheritance Pattern for One Gene in a Family's History
20:30
Symbols
20:46
Trait Being Traced is Depicted by Coloring in the Individual
21:58
Pedigree Example #1
22:26
Pedigree Example #2
25:02
Pedigree Example #3
27:23
Environmental Impact
30:24
Gene Expression Is Often Influenced by Environment
30:25
Twin Studies
30:35
Examples
31:45
Genetic Engineering
36:03
Genetic Transformation
36:17
Restriction Enzymes
39:09
Recombinant DNA
40:37
Gene Cloning
41:58
Polymerase Chain Reaction
43:13
Gel Electrophoresis
44:37
Transgenic Organisms
48:03
IV. History of Life
Evolution

1h 47m 19s

Intro
0:00
The Scientists Behind the Theory
0:04
Fossil Study and Catastrophism
0:18
Gradualism
1:13
Population Growth
2:00
Early Evolution Thought
2:37
Natural Selection As a Sound Theory
8:05
Darwin's Voyage
8:59
Galapagos Islands Stop
9:15
Theory of Natural Selection
11:24
Natural Selection Summary
12:37
Populations have Enormous Reproductive Potential
13:45
Population Sizes Tend to Remain Relatively Stable
14:55
Resources Are Limited
16:51
Individuals Compete for Survival
17:16
There is Much Variation Among Individuals in a Population
17:36
Much Variation is Heritable
18:06
Only the Most Fit Individuals Survive
18:27
Evolution Occurs As Advantageous Traits Accumulate
19:23
Evidence for Evolution
19:47
Molecular Biology
19:53
Homologous Structures
22:55
Analogous Structures
26:20
Embryology
29:36
Paleontology
34:54
Patterns of Evolution
40:14
Divergent Evolution
40:37
Convergent Evolution
43:15
Co-Evolution
46:07
Gradualism vs. Punctuated Equilibrium
49:56
Modes of Selection
52:25
Directional Selection
54:40
Disruptive Selection
56:38
Stabilizing Selection
58:07
Artificial Selection
59:56
Sexual Selection
1:02:13
More on Sexual Selection
1:03:00
Sexual Dimorphism
1:03:26
Examples
1:04:50
Notes on Natural Selection
1:09:41
Phenotype
1:10:01
Only Heritable Traits
1:11:00
Mutations Fuel Natural Selection
11:39
Reproductive Isolation
1:12:00
Temporal Isolation
1:12:59
Behavioral Isolation
1:14:17
Mechanical Isolation
1:15:13
Gametic Isolation
1:16:21
Geographic Isolation
1:16:51
Reproductive Isolation (Post-Zygotic)
1:18:37
Hybrid Sterility
1:18:57
Hybrid Inviability
1:20:08
Hybrid Breakdown
1:20:31
Speciation
1:21:02
Process in Which New Species Forms From an Ancestral Form
1:21:13
Factors That Can Lead to Development of a New Species
1:21:19
Adaptive Radiation
1:24:26
Radiating of Various New Species
1:24:28
Changes in Appearance
1:24:56
Examples
1:24:14
Hardy-Weinberg Theorem
1:27:35
Five Conditions
1:28:15
Equations
1:33:55
Microevolution
1:36:59
Natural Selection
1:37:11
Genetic Drift
1:37:34
Gene Flow
1:40:54
Nonrandom Mating
1:41:06
Clarifications About Evolution
1:41:24
A Single Organism Cannot Evolve
1:41:34
No Single Missing Link with Human Evolution
1:43:01
Humans Did Not Evolve from Chimpanzees
1:46:13
Human Evolution

47m 31s

Intro
0:00
Primates
0:04
Typical Primate Characteristics
1:12
Strepsirrhines
3:26
Haplorhines
4:08
Anthropoids
5:03
New World Monkeys
5:15
Old World Moneys
6:20
Hominoids
6:51
Hominins
7:51
Hominins
8:46
Larger Brains
8:53
Thinner, Flatter Face
9:02
High Manual Dexterity
9:30
Bipedal
9:41
Australopithecines
12:11
Earliest Fossil Evidence for Bipedalism
12:24
Earliest Australopithecines
13:06
Lucy
13:35
The Genus 'Homo'
15:20
Living and Extinct Humans
16:46
Features
16:52
Tool Use
17:09
Homo Habilis
17:38
2.4 - 1.4 mya
18:38
Handy Human
19:19
Found In Africa
19:33
Homo Ergaster
20:11
1.8 - 1.2 mya
20:14
Features
20:25
Found In and Outside of Africa
20:41
Most Likely Hunted
21:03
Homo Erectus
21:32
1.8 - 0.4 mya
22:04
Upright Human
22:49
Found in Africa, Asia, and Europe
22:52
Features
22:57
Used Fire
23:07
Homo Heidelbergensis
23:45
1.3 - 0.2 mya
23:50
Transitional Form
24:22
Features
24:36
Homo Sapiens Neanderthalensis
24:56
0.3 - 0.2 mya
25:23
Neander Valley
25:31
Found in Europe and Asia
21:53
Constructed Complex Structures
27:50
Modern Human and Neanderthal
28:50
Homo Sapiens Sapiens
29:34
195,000 Years Ago - Present
29:37
Humans Most Likely Evolved Once
29:50
Features
30:26
Creative and More Control Over the Environment
30:37
Homo Floresiensis
31:36
18,000 Years Old
31:40
The Hobbit
32:09
Brain and Body Proportions are Similar to Australopithecines
32:16
Human Migration Summary
32:49
Origins of Life

40m 58s

Intro
0:00
Brief History of Earth
0:05
About 4.5 Billion Years Old
0:13
Started Off as a Fiery Ball of Hot Volcanic Activity
1:12
Atmospheric Gas of Early Earth
2:20
Gases Expelled Out of Volcanic Vents
3:10
Building Blocks to Organic Compounds
4:47
Miller-Urey Experiment (1953)
5:41
Stanley Miller and Harold Urey
5:48
Amino Acids Were Found in the Sterile Water Beneath
7:27
Protobionts
8:07
Ancestors of Cells as We Know Them
8:19
Lipid Bubbles with Organic Compounds Inside
8:32
Origin of DNA
12:07
First Cells
12:12
RNA Originally Coded for Protein
12:44
DNA Allows for Retention and a Checking for Errors
12:55
Oxygen Surge
14:57
Photosynthesis Changes Oxygen Gas in Atmosphere
16:36
Cells Absorb Solar Energy with Pigment and Could Make Sugars and Release Oxygen
17:05
Endosymbiotic Theory
18:22
First Eukaryote was Born
19:54
First Proposed by Lynn Margulis
22:43
Multicellular Origins
23:08
Cells That Kept Close Quarters and Stayed Attached Had Safety in Numbers
23:28
Hypothesis
23:45
Cambrian Explosion
26:22
Explosion of Species
27:10
Theory and Snowball Earth
28:24
Timeline of Major Events
32:00
Biogenesis

27m 25s

Intro
0:00
Spontaneous Generation
0:04
Spontaneous Generation
0:14
Pseudoscience
1:45
Individuals Who Sought to Disprove This Theory
2:49
Francesco Redi's Experiment
3:33
17th Century Italian Scientist
3:36
Wanted to Debunk the Theory That Maggots Emerge From Rotting Raw Meat
3:48
Lazzaro Spallanzani's Experiment
6:33
18th Century Italian Scientist
6:36
Wanted to Demonstrate That Microbes Could Be Airborne
6:58
Louis Pasteur's Experiment
9:47
19th Century French Scientist
9:51
Disprove Spontaneous Generation
11:17
Pasteur's Vaccine Discovery
13:47
Motivation to Discover a Way to Immunize People Against Disease
14:00
Cholera Bacteria
14:42
Vaccine Explanation
16:42
Inactive Versions of the Virus are Generated in a Culture
16:47
Antigens Injected Into the Person
17:45
Common Immunizations
22:00
Effectiveness
22:03
No Proof That Vaccines Cause Autism
26:33
V. Diversity of Life
Taxonomy

35m 21s

Intro
0:00
Ancient Classification
0:04
Start of Classification Systems
0:56
How Plants and Animals Were Split Up
2:46
Used in Europe Until 1700s
3:27
Modern Classification
3:52
Carolus Linnaeus
3:58
Taxonomy
5:15
Taxonomic Groups
6:57
Domain
7:14
Kingdom
7:29
Phylum
7:39
Class
7:49
Order
8:02
Family
8:09
Genus
8:25
Species
8:45
Binomial Nomenclature
12:10
Genus Species
12:22
Naming System Rules
12:49
Advantages and Disadvantages to Taxonomy
14:56
Advantages
15:00
Disadvantages
17:53
Domains
20:31
Domain Archaea
21:10
Domain Bacteria
21:19
Domain Eukarya
21:43
Extremophiles
22:48
Kingdoms
25:09
Kingdom Archaebacteria
25:17
Kingdom Eubacteria
25:25
Kingdom Protista
25:52
Kingdom Plantae, Fungi, Animalia
27:18
Cladograms
28:07
Relates Evolution to Phylogeny
28:12
Characteristics Lead to Splitting Off Groups of Organisms
28:20
Viruses

44m 25s

Intro
0:00
Virus Basics
0:04
Non-Living Structures have the Potential to Harm Life on Earth
0:14
Made of Nucleic Acids Wrapped in a Protein Coat
2:15
5 to 300 nm Wide
3:12
Virus Structure
4:29
Icosahedral
4:41
Spherical
5:33
Bacteriophage
6:20
Helical
8:56
How Do They Invade Cells?
11:24
Viruses Can Fool Cells to Let Them In
11:27
Viruses Use the Organelles of the Host
12:29
Viruses are Host Specific
12:57
Viral Cycle
16:18
Lytic Cycle
16:34
Lysogenic Cycle
18:53
Connection Between Lytic/ Lysogenic
23:01
Retroviruses
30:04
Process is Backwards
30:52
Reverse Transcriptase
31:08
Example
31:47
HIV/ AIDS
32:38
Human Immunodeficiency Virus
32:42
Acquired Immunodeficiency Syndrome
36:27
Smallpox: A Brief History
37:06
One of the Most Harmful Viral Diseases in Human History
37:09
History
37:53
Prions
41:32
Infectious Proteins That Damage the Nervous System
41:33
Cause Transmittable Spongiform Encephalopathies
41:51
No Known Cure
43:42
Bacteria

46m 1s

Intro
0:00
Archaebacteria
0:04
Thermophiles
1:10
Halophiles
2:06
Acidophiles
2:29
Methanogens
2:59
Archaea and Bacteria Compared to Eukarya
4:25
Archaea and Eukarya
4:36
Bacteria and Eukarya
5:37
Eubacteria
6:35
Nucleoid Region
7:02
Peptidoglycan
7:21
Binary Fission
8:08
No Membrane-Bound Organelles
8:59
Bacterial Shapes
10:19
Coccus
10:26
Bacillus
12:07
Spirillum
12:44
Bacterial Cell Walls
13:17
Gram Positive
13:47
Gram Negative
15:09
Bacterial Adaptations
16:13
Capsule
16:18
Fimbriae
17:51
Conjugation
18:30
Endospore
21:30
Flagella
23:49
Metabolism
24:36
Benefits of Bacteria
27:28
Mutualism
27:32
Connections to Human Life
30:56
Diseases Caused by Bacteria
35:05
STDs
35:15
Respiratory
36:04
Skin
37:15
Digestive Tract
38:00
Nervous System
38:27
Systemic Diseases
39:09
Antibiotics
40:26
Drugs That Block Protein Synthesis
40:40
Drugs That Block Cell Wall Production
41:07
Increased Bacterial Resistance
41:36
Protists

32m 46s

Intro
0:00
Kingdom Protista Basics
0:04
Unicellular and Multicellular
0:28
Asexual and Sexual
0:48
Water and Land
1:06
Resemble Other Life Forms
1:32
Protist Origin
2:04
Evolutionary Bridge Between Bacteria and Multicellular Eukaryotes
2:06
Protist Ancestors
2:27
Protist Debate
4:18
One Kingdom
4:30
Some Scientists Group Into Separate Kingdoms Based on Genetic Links
4:37
Plant-like Protists
6:03
Photoautotrophs
6:12
Green Algae
6:44
Red Algae
7:12
Brown Algae
7:57
Golden Algae
9:10
Dinoflagellates
9:20
Diatoms
9:41
Euglena
10:17
Euglena Structure
10:39
Ulva Life Cycle
12:08
Fungi-Like Protists
15:39
Heterotrophs That Feed on Decaying Organic Matter
15:41
Found Anywhere with Moisture and Warmth
16:04
Cellular Slime Mold Life Cycle
17:34
Animal-like Protists
21:45
Heterotrophs That Eat Live Cells
21:50
Motile
22:03
Amoeba Life Cycle
25:24
How Protists Impact Humans
29:09
Good
29:16
Bad
32:18
Plants, Part I

54m 22s

Intro
0:00
Kingdom Plantae Characteristics
0:05
Cuticle
0:38
Vascular Bundles
1:18
Stomata
2:51
Alternation of Generations
4:16
Plant Origins
5:58
Common Ancestor with Green Algae
6:03
Appeared on Earth 400 Million Years Ago
7:28
Non-Vascular Plants
8:17
Bryophytes
8:45
Anthoworts
9:12
Hepaticophytes
9:19
Bryophyte (Moss) Life Cycle
9:30
Dominant Gametophyte
9:38
Illustration Explanation
9:58
Seedless Vascular Plants
15:26
Do Not Reproduce With Seeds
15:33
Sori
15:42
Lycophytes
15:54
Pterophytes
16:30
Pterophyte (Fern) Life Cycle
17:05
Dominant Generation
17:08
Produce Motile Sperm
17:17
Seed Plants
23:17
Most Vascular Plants Have Seeds
23:25
Cotyledons
23:43
Gymnosperm vs. Angiosperm
24:50
Divisions
25:48
Coniferophytes (Cone-Bearing Plants)
27:05
Examples
27:07
Evergreen or Deciduous
27:44
Gymnosperms
28:26
Economic Importance
29:28
Conifer Life Cycle
30:10
Dominant Generation
30:13
Cones Contain the Gametophyte
30:25
Illustration Explanation
30:31
Anthophytes (Flowering Plants)
38:01
Every Plant That Has Flowers
38:03
Angiosperms
38:28
Various Life Spans
38:03
Flower Anatomy
40:25
Female Parts
40:54
Male Parts
42:49
Flowering Plant Life Cycle
44:48
Dominant Generation
44:56
Flowers Contain the Gametophyte
45:05
Plants, Part II

44m 40s

Intro
0:00
Plant Cell Varieties
0:05
Parenchyma
0:11
Collenchyma
1:37
Sclerenchyma
2:03
Specialized Tissues
2:56
Plant Tissues
3:17
Meristematic Tissue
3:21
Dermal Tissue
6:46
Vascular Tissues
8:45
Ground Tissue
13:56
Roots
14:24
Root Cap
15:59
Cortex
16:17
Endodermis
17:02
Pericycle
17:42
Taproot
18:11
Fibrous
18:20
Modified
18:49
Stems
19:49
Tuber
21:43
Rhizome
21:58
Runner
22:12
Bulb and Corm
22:49
Leaves
23:06
Photosynthesis
23:09
Leaf Parts
23:32
Gas Exchange
25:55
Transpiration
26:25
Seeds
27:41
Cotyledons
28:42
Seed Coat
29:29
Endosperm
29:37
Embryo
30:10
Radicle
30:27
Epicotyl
31:57
Fruit
33:49
Fleshy Fruits
34:46
Aggregate Fruits
35:17
Multiple Fruits
35:50
Dry Fruits
36:27
Plant Hormones
37:44
Definition or Hormones
37:48
Examples
38:12
Plant Responses
40:42
Tropisms
41:00
Nastic Responses
43:04
Fungi

26m 20s

Intro
0:00
Fungi Basics
0:03
Characteristics
0:09
Closely Related to Kingdom Animalia
2:33
Fungal Structure
2:58
Hypae
3:03
Mycelium
5:00
Spore
5:24
Reproductive Strategies
6:15
Fragmentation
6:23
Budding
6:35
Spore Production
7:03
Zygomycota (Molds)
7:50
Sexual Reproduction
8:04
Dikaryotic
9:47
Stolons
10:32
Rhizoids
10:53
Ascomycota (Sac Fungi)
11:43
Largest Phylum of Fungi on Earth
11:47
Ascus
12:20
Conidia
12:30
Example
12:46
Basidiomycota (Club Fungi)
14:51
Basidium
15:14
Common Structures In These Fungi
15:37
Examples
16:17
Deuteromycota (Imperfect Fungi)
17:25
No Known Sexual Life Cycle
17:31
Penicillin
18:00
Benefits of Fungi
18:51
Mutualism
18:56
Food
21:41
Medicines
22:30
Decomposition
23:08
Fungal Infections
23:38
Athlete's Foot
23:44
Ringworm
24:09
Yeast Infections
24:27
Candidemia
24:56
Aspergillus
25:15
Fungal Meningitis
25:44
Animals, Part I

35m 28s

Intro
0:00
Animal Basics
0:05
Multicellular Eukaryotes
0:12
Motility
0:27
Heterotrophic
0:47
Sexual Reproduction
0:57
Symmetry
1:14
Gut
1:26
Cephalization
1:40
Segmentation
1:53
Sensory Organs
2:09
Reproductive Strategies
3:07
Gonads
3:17
Fertilization
4:01
Asexual
4:53
Animal Development
7:27
Zygote
7:29
Blastula
7:50
Gastrula
9:07
Embryo
12:57
Symmetry
13:17
Radial Symmetry
14:14
Bilateral Symmetry
15:26
Asymmetry
16:34
Body Cavities
17:22
Coelom
17:24
Acoelomates
18:39
Pseudocoelomates
19:15
Coelomates
19:40
Major Animal Phyla
20:47
Phylum Porifera
21:15
Phylum Cnidaria
21:33
Phylum Platyhelmininthes, Nematoda, and Annelida
21:44
Phylum Rotifera
21:56
Phylum Mollusca
22:13
Phylum Arthropoda
22:34
Phylum Echinodermata
22:48
Phylum Chordata
23:18
Phylum Porifera
25:15
Sponges
25:23
Oceanic or Aquatic
26:07
Adults are Sessile
26:26
Structure
27:09
Sexual or Asexual Reproduction
28:31
Phylum Cnidaria
28:49
Sea Jellies, Anemonse, Hydrozoans, and Corals
28:57
Mostly Oceanic
30:42
Body Types
31:32
Cnidocytes
33:06
Nerve Net
34:55
Animals, Part II

48m 42s

Intro
0:00
Phylum Platyhelminthes
0:04
Flatworms
0:14
Acoelomates
0:33
Terrestrial, Oceanic, or Aquatic
0:46
Simple Nervous System
2:46
Reproduction
3:38
Phylum Nematoda
4:20
Unsegmented Roundworms
4:25
Pseudocoelomates
4:34
Terrestrial, Oceanic, or Aquatic
4:53
Full Digestive Tract
5:29
Reproduction
7:07
C. Elegans
7:24
Phylum Annelida
8:11
Segmented Roundworms
8:20
Terrestrial, Oceanic, or Aquatic
8:42
Full Digestive Tract
8:56
Accordion-like Movement
11:26
Simple Nervous System
12:31
Sexual Reproduction
13:40
Class Oligochaeta
14:47
Class Polychaeta
14:56
Class Hirudinea
15:13
Phylum Rotifera
16:11
Pseudocoelomates
16:26
Terrestrial, Aquatic
16:42
Digestive Tract
16:56
Phylum Mollusca
18:55
Snails, Slugs, Clams, Oysters
19:00
Terrestrial, Oceanic, or Aquatic
19:14
Mantle
19:29
Full Digestive Tract with Specialized Organs
21:10
Sexual Reproduction
24:29
Major Classes
24:58
Phylum Arthropoda
28:16
Insects, Arachnids, Crustaceans
28:19
Terrestrial, Oceanic, or Aquatic
28:41
Head, Thorax, Abdomen
28:50
Excretion with Malpighian Tubes
32:48
Arthropod Groups
34:06
Phylum Echinodermata
38:32
Sea Stars, Sea Urchins, Sand Dollars, Sea Cucumbers
38:37
Oceanic or Aquatic
39:36
Water Vascular System
39:43
Full Digestive Tract
40:38
Sexual Reproduction
42:01
Phylum Chordata
42:16
All Vertebrates
42:22
Terrestrial, Oceanic, or Aquatic
42:40
Main Body Parts
42:49
Mostly in Subphylum Vertebrata
44:54
Examples
45:14
Animals, Part III

35m 45s

Intro
0:00
Characteristics of Subphylum Vertebrata
0:04
Vertebral Column
0:16
Neural Crest
0:38
Internal Organs
1:24
Fish Characteristics
2:05
Oceanic or Aquatic
2:16
Locomotion with Paired Fins
3:15
Gills
4:18
Fertilization
8:14
Movement
8:30
Fish Classes
8:58
Jawless Fishes
9:06
Cartilaginous Fishes
10:07
Bony Fishes
10:46
Amphibian Characteristics
12:22
Tetrapods
12:29
Moist Skin
14:22
Circulation
14:39
Nictitating Membrane
16:36
Tympanic Membrane
16:56
External Fertilization is Typical
17:34
Amphibian Orders
18:20
Order Anura
18:27
Order Caudata
19:15
Order Gymnophiona
19:59
Reptile Characteristics
20:31
Dry, Scaly Skin
20:37
Lungs for Gas Exchange
22:00
Terrestrial, Oceanic, Aquatic
22:12
Ectothermic
23:07
Internal Fertilization
24:13
Reptile Orders
26:28
Order Squamata
26:33
Order Crocodilia
27:32
Order Testudinata
27:55
Order Sphenodonta
28:30
Bird Characteristics
28:43
Feathers
29:42
Lightweight Bones
31:33
Lungs with Air Sacs
32:25
Endothermic
33:47
Internal Fertilization
34:03
Bird Orders
34:13
Order Passeriformes
34:29
Order Ciconiiformes
34:46
Order Sphenisciformes
34:55
Order Strigiformes
35:20
Order Struthioniformes
35:25
Order Anseriformes
35:38
Mammals

38m 39s

Intro
0:00
Mammary Glands and Hair
0:04
Class Mammalia Name
0:20
Hair Functions
1:53
Metabolic Characteristics
3:58
Endothermy
4:01
Feeding
4:48
Mammalian Organs
8:43
Respiratory System
8:47
Circulation
9:26
Brain and Senses
10:29
Glands
11:56
Mammalian Reproduction
12:55
Live Birth
13:03
Placental
13:17
Marsupial
14:41
Gestation Periods
16:07
Infraclass Marsupialia
17:42
Australia
17:59
Uterus/ Pouch
18:33
Origins
18:53
Examples
19:24
Order Monotremata
20:21
Egg Layers
20:25
Platypus, Echidna
20:55
Shoulder Area Has a Reptilian Bone Structure
21:07
Order Insectivora
22:21
Insectivores
22:23
Pointy Snouts
22:32
Burrowing
22:53
Examples
23:10
Order Chiroptera
23:32
True Flying Mammalian Order
23:38
Wings
23:59
Feeding
24:21
Examples
25:08
Order Xenarthra
25:14
Edentata
25:18
No Teeth
25:23
Location
25:50
Examples
25:55
Order Rodentia
26:33
40% of Mammalian Species
26:38
2 Pairs of Incisors
26:45
Examples
27:28
Order Lagomorpha
28:06
Herbivores
28:30
Examples
28:41
Order Carnivora
29:19
Teeth
29:36
Examples
29:42
Order Proboscidea
30:37
Largest Living Terrestrial Mammals
30:40
Trunks
30:48
Tusks
31:12
Examples
31:33
Order Sirenia
32:01
Large, Slow Moving Aquatic Mammals
32:15
Flippers
32:26
Herbivores
32:37
Examples
32:42
Order Cetacea
32:46
Large, Mostly Hairless Aquatic Mammals
32:50
Flippers
33:06
Fluke
33:18
Blowhole
33:29
Examples
34:10
Order Artiodactyla
34:30
Even-Toed Hoofed Mammals
34:33
Herbivores
34:37
Sometimes Grouped with Cetaceans
34:52
Examples
35:35
Order Perissodactyla
35:57
Odd-Toed Hoofed Mammals
36:00
Herbivores
36:12
Examples
36:27
Order Primates
36:30
Largest Brain-to-Body Ratio
36:35
Arboreal
37:03
Nails
37:33
Examples
38:29
Animal Behavior

29m 55s

Intro
0:00
Behavior Overview
0:04
Behavior
0:08
Origin of Behavior
0:36
Competitive Advantage
1:26
Innate Behaviors
2:05
Genetically Based
2:07
Instinct
2:13
Fixed Action Pattern
3:31
Learned Behavior
5:13
Habituation
5:26
Classical Conditioning
6:31
Operant Conditioning
7:51
Imprinting
10:17
Learned Behavior That Can Only Occur in a Specific Time Period
10:20
Sensitive Period
10:28
Cognitive Behaviors
11:53
Thinking, Reasoning, and Processing Information
12:02
Examples
12:22
Competitive Behaviors
14:40
Agonistic Behavior
14:46
Dominance Hierarchies
15:23
Territorial Behaviors
16:19
More Types of Behavior
17:05
Foraging Behaviors
17:08
Migratory Behaviors
17:53
Biological Rhythms
19:15
Communication Behaviors
20:37
Pheromones
20:52
Auditory Communication
22:18
Courting and Nurturing Behaviors
23:42
Courting Behaviors
23:45
Nurturing Behaviors
26:04
Cooperative Behaviors
26:47
Benefit All Members of the Group
27:01
Example
27:08
VI. Ecology
Ecology, Part I

1h 7m 26s

Intro
0:00
Ecology Basics
0:05
Ecology
0:18
Biotic vs. Abiotic Factors
1:25
Population
2:23
Community
2:45
Ecosystem
3:04
Biosphere
3:27
Individuals and Survival
4:13
Habitat
4:23
Niche
4:37
Symbiosis
7:07
Obtaining Energy
11:14
Producers
11:24
Consumers
13:31
Food Chain
17:11
Model to Illustrate How Matter Moves Through Organisms in an Ecosystem
17:15
Examples
18:31
Food Web
20:29
Keystone Species
22:55
Three Ecological Pyramids
27:28
Pyramid of Energy
27:38
Pyramid of Numbers
31:39
Pyramid of Biomass
34:09
The Water Cycle
37:24
The Carbon Cycle
40:19
The Nitrogen Cycle
43:34
The Phosphorus Cycle
46:42
Population Growth
49:35
Reproductive Patterns
51:58
Life History Patterns Vary
52:10
r-Selection
53:30
K-Selection
56:55
Density Factors
59:02
Density-Dependent Factors
59:29
Density-Independent Factors
1:02:21
Predator / Prey Relationships
1:03:59
Ecology, Part II

50m 50s

Intro
0:00
Mimicry
0:05
Batesian Mimicry
0:38
Müllerian Mimicry
1:53
Camouflage
3:23
Blend In with Surroundings
3:38
Evade Detection by Predators
3:43
Succession
5:22
Primary Succession
5:40
Secondary Succession
7:44
Biomes
9:31
Terrestrial
10:08
Aquatic / Marine
10:05
Desert
11:20
Annual Rainfall
11:24
Flora
13:35
Fauna
14:15
Tundra
14:49
Annual Rainfall
15:00
Permafrost
15:50
Flora
16:06
Fauna
16:40
Taiga (Boreal Forest)
16:59
Annual Rainfall
17:14
Largest Terrestrial Biome
17:33
Flora
18:37
Fauna
18:49
Temperate Grassland
19:07
Annual Rainfall
19:28
Flora
20:14
Fauna
20:18
Tropical Grassland (Savanna)
20:41
Annual Rainfall
21:01
Flora
21:56
Fauna
22:00
Temperate Deciduous Forest
22:19
Annual Rainfall
23:11
Flora
23:45
Fauna
23:50
Tropical Rain Forest
24:11
Annual Rainfall
24:16
Flora
27:15
Fauna
27:49
Lakes
28:05
Eutrophic
28:21
Oligotrophic
28:29
Zones
29:34
Estuaries
32:56
Area Where Freshwater and Salt Water Meet
33:00
Mangrove Swamps
33:12
Nutrient Traps
33:52
Organisms
34:24
Marine
34:50
Euphotic Zone
35:16
Pelagic Zone
37:11
Abyssal Plain
38:15
Conservation Summary
40:03
Biodiversity
40:33
Habitat Loss
44:06
Pollution
44:55
Climate Change
47:03
Global Warming
47:06
Greenhouse Gases
47:48
Polar Ice Caps
49:01
Weather Patterns
50:00
VII. Laboratory
Laboratory Investigation I: Microscope Lab

24m 51s

Intro
0:00
Light Microscope Parts
0:06
Microscope Use
6:25
Mount the Specimen
6:28
Place Slide on Stage
7:29
Ensure Specimen is Above Light Source
8:11
Lowest Objective Lens Faces Downward
8:34
Focus on the Image
9:36
Adjust the Nosepiece If Needed
9:49
Re-Focus
9:57
Human Skin Layers
10:42
Plants Cells
13:43
Human Lung Tissue
15:20
Euglena
18:26
Plant Stem
20:43
Mold
22:57
Laboratory Investigation II: Egg Lab

11m 26s

Intro
0:00
Egg Lab Introduction
0:06
Purpose
0:09
Materials
0:37
Time
1:24
Day 1
1:28
Day 2
3:59
Day 3
6:05
Analysis
7:50
Osmosis Connection
10:24
Hypertonic
10:36
Hypotonic
10:49
Laboratory Investigation III: Carbon Dioxide Production

14m 34s

Intro
0:00
Carbon Dioxide Introduction
0:06
Purpose
0:09
Materials
0:56
Time
2:39
Part I
2:41
Put Water in Large Beaker
3:09
Exhale Into the Water
3:15
Add a Drop of Phenolphthalein
4:31
Add NaOH
5:33
Record the Amount of Drops
6:10
Part II
6:24
Add HCL
6:39
Exercise for Five Minutes
7:26
Return and Re-Do the Exhaling
7:58
Analysis
9:11
Aerobic Respiration Connection
13:18
As Aerobic Respiration Occurs In Cells, Carbon Dioxide Is Produced
13:21
Increase Output of Carbon Dioxide
13:29
Number of Exhalations Increase
14:17
Laboratory Investigation IV: DNA Extraction Lab

10m 38s

Intro
0:00
DNA Lab Introduction
0:06
Purpose
0:09
Materials
0:45
Time
2:03
Part I
2:06
Pour Sports Drink Into the Small Cup
2:08
When Time Expires, Spit Into the Cup
2:53
Add Cell Lysate Solution
3:21
Let it Sit for a Couple Minutes
4:04
Part II
4:10
Slowly Add Cold Ethanol
4:13
DNA Will Creep Up Into the Ethanol Layer
5:01
Analysis
5:59
DNA Structure Connection
8:49
DNA is Microscopic
8:54
Visible DNA
9:39
Extracted DNA
9:49
Laboratory Investigation V: Onion Root Tip Mitosis Lab

13m 12s

Intro
0:00
Mitosis Lab Introduction
0:06
Purpose
0:09
Materials
0:57
Time
1:42
Part I
1:49
Mount the Slide and Zoom Into the Root Apical Meristem
1:50
Zoom In
3:00
Count the Cells in Each Phase
3:09
Record Your Results
3:52
Microscope View Example
3:58
Part II
6:49
Move to Another Part of the Root Apical Meristem
6:55
Count the Phases in this Second Region
7:02
Analysis
9:07
Mitosis Connection
11:17
Rate of Mitosis Varies from Species to Species
11:21
Mitotic Rate Was Higher Since We Used An Actively Dividing Tissue
12:16
Laboratory Investigation VI: Inheritance Lab

13m 55s

Intro
0:00
Inheritance Lab Introduction
0:05
Purpose
0:09
Materials
0:53
Time
2:00
Explanation
2:03
Basic Procedure
5:03
Analysis
8:00
Inheritance Laws Connection
11:23
Law of Segregation
11:31
Law of Independent Assortment
12:49
Laboratory Investigation VII: Allele Frequencies

14m 11s

Intro
0:00
Allele Frequencies Introduction
0:05
Purpose
0:08
Materials
1:34
Time
2:10
Part I
2:12
Part II
7:05
Analysis
7:51
Evolution Connection
10:45
Meant to Stimulate How a Population's Allele Frequencies Change Over Time
10:47
Particular Phenotypes Selected
11:31
Recessive Allele Keeps Dropping
12:18
Laboratory Investigation VIII: Genetic Transformation

16m 42s

Intro
0:00
Genetic Transformation Introduction
0:06
Purpose
0:09
Materials
0:57
Time
3:31
Set-Up
4:18
Starter Culture with E. Coli Colonies
4:21
Just E. Coli
5:37
Ampicillin with No Plasmid
6:24
Ampicillin with Plasmid
7:11
Ampicillin with Plasmid and Arabinose
7:33
Procedure
8:35
Analysis
13:01
Genetic Transformation Connection
14:59
Easier to Transform Bacteria Than a Multicellular Organism
15:03
Desired Trait Can be Expressed from the Bacteria
15:52
Numerous Applications in Medicine
16:04
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Viruses

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
  • Virus Basics 0:04
    • Non-Living Structures have the Potential to Harm Life on Earth
    • Made of Nucleic Acids Wrapped in a Protein Coat
    • 5 to 300 nm Wide
  • Virus Structure 4:29
    • Icosahedral
    • Spherical
    • Bacteriophage
    • Helical
  • How Do They Invade Cells? 11:24
    • Viruses Can Fool Cells to Let Them In
    • Viruses Use the Organelles of the Host
    • Viruses are Host Specific
  • Viral Cycle 16:18
    • Lytic Cycle
    • Lysogenic Cycle
    • Connection Between Lytic/ Lysogenic
  • Retroviruses 30:04
    • Process is Backwards
    • Reverse Transcriptase
    • Example
  • HIV/ AIDS 32:38
    • Human Immunodeficiency Virus
    • Acquired Immunodeficiency Syndrome
  • Smallpox: A Brief History 37:06
    • One of the Most Harmful Viral Diseases in Human History
    • History
  • Prions 41:32
    • Infectious Proteins That Damage the Nervous System
    • Cause Transmittable Spongiform Encephalopathies
    • No Known Cure

Transcription: Viruses

Hi, welcome back to www.educator.com, this is the lesson on viruses.0000

Some virus basics, what are these things?0005

We are not talking about the computer kind.0008

The computer kind is named after the actual biological virus.0010

They are non-living structures that have the potential to harm every other life form on earth.0014

I do not want you to think that one single virus, like one type of virus can infect everything on its own.0020

That is not what I mean, I mean that any life form you can think of, bacteria, fungus, amoebas, plants, any animal,0027

there is a virus that can invade its body and potentially kill it.0036

That is amazing to think about, the viruses being so tiny can be so harmful.0041

They are considered non-living, why?0047

For talking about them in biology and they are able to invade and infect living beings, what makes them not alive?0051

Couple of main reasons, they cannot metabolize nutrients.0058

When we think of every single other life form, it is made of cells.0062

A virus technically is not made of cells and because of that, because it does not have does cellular parts like ribosomes0067

and other particular enzymes to actually break down nutrients to get energy, we cannot consider it technically alive.0074

It does not have the ability to do that.0083

It actually takes advantage of the hosts ability to do that, so that it can make more copies of itself.0085

Along with that, it cannot replicate without a host.0091

There actually are some living parasites that this is true of as well.0095

There are some parasites that have to be in an animal body to reproduce and then0100

they leave that animal body, invade another animal, and so on.0105

These two reasons combined are major part of why viruses are not in the taxonomic groups.0108

Typically they are not considered alive.0115

Some scientists do not necessarily agree with that.0119

As time goes on and they are studied more, perhaps the definition of what life is maybe adjusted to include viruses.0122

But currently, when you look in most biology textbooks or resources, viruses are not considered living.0129

What are they structurally?0135

They are made of nucleic acids, DNA and RNA, wrapped in a protein coat and that is known as a capsid.0137

Here you are seeing a computer generated image of a virus.0143

All of this blue green stuff that is the capsid, that is the protein and these are known as antigens,0148

little protein unit sticking out of it.0156

Inside, you have either DNA or RNA.0158

Viruses are either DNA viruses or RNA viruses.0161

That is the bare minimum, to be a virus is this protein coat or wrapping around genetic information.0165

Viruses can have other tools, they can have an additional membrane on top of their capsid.0172

They sometimes have little enzymes inside of them.0177

But you do not see cellular parts, you do not see ribosomes, you do not see organelles.0180

They are usually very tiny compared to even a bacterial cell.0187

Most viruses are 5 to 300 nm wide.0193

A nanometer is a billionth of a meter.0198

Billionth, that means in 1 m there is 1 billion nm.0207

Typically with measuring cells that are alive and much bigger, you are going to use the micrometer.0214

A micrometer is a millionth of a meter.0221

In 1 nm there are a thousand of these micrometers.0224

That is a very huge size difference.0230

That is a distinction to make because many viruses, if you lay them end to end to end,0232

a thousand of them across can fit in one cell.0237

Very huge difference in the ratio sizes from the average cell.0243

And the virus that would invade that cell and kick its butt.0248

Speaking of how many viruses you can fit in a space, I have seen this amazing fact that,0251

in the average period, at the end of the sentence, you can fit 10,000 cold viruses, side by side in that period.0257

So incredibly tiny.0266

Virus structures, there is two different kinds to keep in mind.0270

This is the first slide on virus structure.0274

There are a few major classes that occur in nature.0276

You could have viruses beside this, I’m going to give you the 4 main ones.0279

Here is an actual micrograph with an electron microscope, of what these look like.0282

Here is a computer generated image of what is called an adenovirus,0287

these are typically causing respiratory infections like the cold.0290

Common cold is an adenovirus.0295

It is Icosahedral, in terms of the geometry of this.0297

It is a lot of amino acids side by side, in triangular shapes.0300

Those triangles all together can make a slightly spherical form.0305

But because of the triangle points, it does have these little pointy edges.0310

You have got what are called antigens here, these little protein units sticking out from there.0315

These little units sticking off in the adenovirus are kind of like the key that fits into the lock of the whole cell that it is going to invade.0321

I will tell you more about that, later on in this lesson.0329

Another virus, spherical, truly spherical, you do not see those little pointy edges.0334

You still do have these projections coming out from the outside.0339

A very common spherical shaped virus is influenza.0344

This causes the flu, there is influenza A, B.0348

There is a lot of different strains of the flu virus.0352

You can see it in action here.0355

You actually have a lot going on in this flu virus.0359

The capsid is this inner part here, that is the protein layer, the bullish purple part.0363

In this part that is a little bit more magenta is a lipid envelope on the outside,0371

just another structural tool that this virus has.0376

A couple more virus structures, bacteriophages.0382

Bacteriophages strictly invade bacteria.0385

They can get inside of your body but they are not going to be able to invade your bodily cells.0390

Here is a micrograph of what they look like, pretty interesting.0395

And then, this is a computer generated image.0399

You can see something that is hard to tell in this micrograph, these things called tail fibers.0403

These things that look like legs are actually called tail fibers.0408

Oftentimes, this part is called the tail, I have also heard it called a neck or a mid piece.0418

Here is the head or the capsid.0424

Inside you got genetic material of DNA and RNA.0429

Oftentimes it is DNA with bacteriophages.0432

This invades bacterial cells like E coli, salmonella.0435

It is specialized to invade a bacterium, take advantage of its parts inside, make more copies of itself and bust out of there.0439

The way that it actually gets inside of the cells are very interesting.0447

Normally, you do not see all of this protein stuff that looks like an alien spaceship.0450

You do not see that going inside of the host bacterium.0456

They will just squirt their genetic information in.0459

Once that is inside, typically the bacterium is toast, unless it has restriction enzymes0462

which you will hear more about in other lessons in this course.0468

As long as it gets in and this is how it does, I’m going to do a little impersonation for you.0472

Let us say that my tablet here is the cell wall.0477

The outside surface of the cell wall, the host I want to invade.0481

I’m the bacteriophage, my arms here are the tail fibers.0484

I land here and they can do a stapling action.0488

That stapling action, kind of, in one instant will not only allow the squirting of the DNA into the bacterium.0492

The way that it gets inside is there is a little bunch of enzymes here that cause kind of destruction, I’m making little splash here.0503

You are making a whole in the cell wall, those enzymes is almost like strapping C4 on the wall and blowing up.0517

It gets a big hole in the cell wall so that it can actually get the DNA inside of it, pretty cool.0528

Another kind of viral shape, helical.0537

You can see that the arrangement of the amino acids here is in that spiral shape that we see with DNA.0539

It kind of looks like a rod.0546

This is up close, you can see there is 18 nm diameter here.0548

We are looking actually at a very small part of what looks like a long rod.0554

This whole thing is the virus, these are three viruses here, 300 nm long each.0559

When we zoom into little part, you can see structurally a little bit more detail.0564

Here is the RNA that is inside of the hollowed out center of this helical virus.0569

TMV that stands for tobacco mosaic virus, this invades plants.0575

Not just the tobacco plant but that is where it was discovered.0590

This tobacco mosaic virus TMV, can invade tobacco plants and relatives of that plant.0593

Here is an amazing story that I have heard about TMV.0600

You could potentially have this virus in tobacco leaves, before a farmer whose growing them even knows it.0602

Before the virus has spread throughout the leaf to cause damage that can be seen.0609

The farmer and his workers, they pick the leaves, dry them out, shred them up.0614

Sell them to cigarette companies so that they can put them in their cigarettes .0620

After the drying out of the leaf and the shredding of the leaf, the virus is still intact inside those dried out dead cells.0627

The virus can remain there.0635

The amazing thing is the shredded up tobacco can end up in cigarettes.0637

A person could take a cigarette out of one of those packages, light it up, inhale it0641

and then it had the virus actually come into their lungs through that inhaled vapor.0647

They could exhale it on another tobacco plant, a relative of that and the virus could get into the new plants.0654

It is not going to invade the lung tissue of the person who is smoking because TMC specifically is a plant virus.0663

It cannot actually invade animal cells, the proteins are too different.0670

But what is amazing is that it can survive the drying out, the vaporization thing.0675

They are so tiny, they just can hang with it.0680

How do they actually invade cells?0685

Viruses have the ability, thanks to their genetic code, to fool cells into letting them in.0687

Supposedly viruses have been around, ever since cells have been around.0692

Cells have evolved, as viruses have evolved.0695

There are genes in the viruses that allow them to mimic protein structure that gets them to fool the host cell.0700

Like I said earlier with that key and lock analogy, it is a good way to put it because0709

they slip through the outer membrane or cell wall of the cell and get in there.0714

That is how they actually do their dirty work.0720

Either the whole virus enters, it can actually completely pass through the plasma membrane0722

or just the DNA and RNA is inserted, like in the case of a bacteriophage.0728

Sometimes with viruses, more will go in besides just the genetic info like with RNA viruses called retroviruses.0734

There is also a very important enzyme that the virus has to get inside of the cell.0742

More on that, a little bit later in this lesson.0746

Viruses usually use the organelles of the host to make more copies of themselves.0749

That is how they actually can be successful and propagate, meaning make more parts, make more viruses.0753

Once they have used the cell, used and abused it, they typically leave, killing the cell.0762

And they move on to another host and do the same thing all over again.0769

It is almost like they are little organic machines.0773

Viruses are host specific, I have hinted at this earlier in the lesson.0776

Plant viruses do not invade animals.0780

When we look at in animal viruses vice versa would not invade plants.0783

When we look at different animals, you also have host specificity based on the type of animal.0788

Occasionally, it can hop around to different species.0795

Let me give you some examples.0798

Since the proper membrane, proteins must be accessed.0801

Viruses typically only can enter one type of host.0804

Viruses that infect us humans, most of the time they are just infecting humans.0808

It would not be that hard for them to hop to a chimpanzee or a gorilla because0814

they are very closely related to us compared to other animals.0818

To go from us to a sea jelly which is not closely related, that is a big jump.0823

The proteins are way too different.0828

Some exceptions to this can exist.0831

You have heard about some of these in the news, potentially.0833

Avian flu also known as bird flu, affecting humans.0836

Several years ago, this was a major epidemic.0840

Avian flu typically just infects birds, it mutated just enough to affect the lung tissue of humans.0844

It could happen in reverse, a human virus can potentially mutate to infect birds.0857

It is possible.0862

You may have heard of swine flu, the actual better term for what that was is H1N1.0864

A lot of viruses are being presented or named with a letter and number combination,0872

to keep them straight into identifying one vs. the other.0878

H1N1, supposedly that started in a population of pigs and got into human population, it affected us.0882

It is still around but it certainly has calmed down, in terms of how widespread it is.0891

HIV origin, where did HIV originally come from?0898

It did not just randomly pop up in the late 70’s or early 80’s.0902

That is when it did become widespread enough as an epidemic to get a lot of press and media,0906

and people started hearing about it, and it was named and so on.0911

Then, we figure out more about how it spread from person to person.0916

I have more about HIV later on in this lesson.0919

In terms of what it actually started, there are guesses, in terms of what decade it originally entered a human.0923

There is a good chance that it came from a chimpanzee.0930

One of the theories I have heard is that, someone in Africa was potentially butchering a chimp for food.0933

If that chimp had HIV in its bloodstream, some of that blood spattering on the person who is butchering them.0941

If they had a cut, it is possible that the virus could have been transmitted into them from the chimpanzee.0949

If it mutated just a little bit, it can hop from the genome of the chimp to ours, because that is 98.5% the same.0959

It is not that farfetched to think of that, possibly being the origin of the HIV.0969

It could come from another primate species.0975

Viral cycles, viruses have a way that they reproduce.0980

Just like when we look at cells with mitosis or you look at binary fission of bacteria.0984

Viruses have this pattern that is predictable, in terms of how they make more viruses.0989

The first cycle I want to tell you about is the lytic cycle.0994

You will see in the next slide, I will also tell you about the lysogenic cycle which is a longer word.0999

The lytic cycle in a sense, is a short term assault.1004

The way that I remember that is lytic is a shorter word and it is more of the short term of how it gets inside of the host cell,1008

takes advantage of its parts, and then quickly leaves and destroys it.1020

A lysogenic can be much more drawn out, as you will see in the next slide.1024

A virus invades a host cell in the lytic cycle, makes copies of itself, and leaves the host, and leaves it dead.1028

Once it out of there, the cell, does not much have you can do, the contents of the cell leak out, it is done.1036

There are five main steps, attachment.1043

I will draw this for you in a couple of slides.1045

Attachment, the virus physically makes contact with the host.1049

Sometimes, it just squirts in its DNA or RNA.1052

Sometimes the whole cell actually goes in and that would be entry.1055

Entry of the genetic info or the whole virus.1059

Replication, the DNA inside the virus is going to be replicated with enzymes like DNA polymerase which were inside the host.1063

It uses the host’s enzymes to do that.1071

DNA is still phosphate sugar base, when you look at a virus.1073

It still has that 3 prime to 5 prime designation and 5 prime to 3 prime thing going on.1077

It is also going to use that replicated DNA to make RNA.1082

That RNA will be read at the ribosomes of the host.1088

It is going to make all kinds of viral parts, for talking a bacteriophage,1090

it is going to make the tail, the tail fibers, the capsids, all those parts.1095

And then finally, those parts are assembled, they are put together with the new pieces of DNA inside the capsids.1100

It will be hundreds, sometimes thousands of virus from a single host.1107

And then finally, the release, they have a way of busting out of there.1112

Oftentimes, I just call the release stage busting out.1117

This is actually a micrograph of viruses in the process of docking on host,1122

which you can see here is the membrane and getting inside of there.1126

That is the lytic cycle.1132

The next viral cycle is lysogenic.1134

Like I mentioned earlier, this is that longer name.1142

It is typically more of a drawn out cycle, you will see why.1144

A virus invades a host cell here, inserts its genetic info into the host genome, that is different than lytic.1150

This time the DNA from the virus sneaks into the chromosome of the host.1156

It can lie dormant, for sometimes years, it really depends on the virus, it depends on the chemical factors.1163

I will give you an example in a second, with this particular picture which I know is not pleasant to look at.1171

The steps, if a virus was into a host and starts with the lysogenic cycle, the first two steps are identical to lytic.1176

First, the virus attaches to the surface and enters.1184

Sometimes, just like the genetic info or the whole virus enters.1188

Step three, it is different, it does not go to replication this time.1192

It goes to a provirus state.1196

I will show you on the next slide with a drawing of what provirus is.1199

It is basically the virus inserting its genetic info inside of the hosts genome.1203

From that point in time, the host unbeknownst to it, it just does what it normally does.1211

It eventually divides, copies all its DNA which means it is also copying the provirus, passes that on to daughter cells.1218

The daughters cells eventually divide.1226

This keeps happening where the viral DNA, which has been sucked into the host, keeps getting copied and passed on.1228

You can have potentially millions and millions of cells, as a result of these cell divisions.1235

Eventually, someday, it could be hours later, but sometimes it could be years later,1243

the provirus gets released out of these daughters cells, and then you go back to lytic.1249

Then it goes back to that step three of lytic where, now that the viral DNA has been released out,1255

copy it, make RNA from it, make viral parts, etc.1261

And then eventually, it is going to conclude with the virus wreaking habit and destroying those cells.1265

This particular image here, this is shingles.1273

I do not mean shingles on a roof, this is actually the chickenpox virus back with a vengeance, that is what shingles is.1281

I have had a chickenpox virus. I had it when I was about 6 or 7 years old.1289

I got over it, the virus went away, supposedly.1296

That is not necessarily the case, what could have happened with this chickenpox virus is1302

my immune system fought it off, my skin healed.1306

I no longer have that little pox, little red marks that are itchy.1309

What could happen is, surviving viruses, viruses that remain,1314

did not get destroyed by immune system actually went into this lysogenic cycle in some of the cells of my body.1319

And then years later, sometimes people who have chickenpox, approximately,1328

I have heard 1/3 of people with chickenpox will get shingles.1333

Where some chemical factors maybe it is stress, who knows, there are various theories about what brings it out.1336

Chemical factors in the body bring this chickenpox virus back and it comes back with a vengeance.1343

These rashes that tend to be concentrated on the torso, the front and the back,1350

they really burn and they hurt way more than the chickenpox virus.1355

That shingles, the lysogenic virus is what connects the original chickenpox virus to this virus,1361

that now has gone back in the lytic cycle and wreaks havoc on the person's body.1370

Maybe one day, in my 50’s or 60’s,I can get shingles, I hope I do not.1375

Here is the connection between the lytic and lysogenic.1382

I want to give you a little play by play here.1384

The lytic I’m going to use blue arrows, for the lysogenic I’m going to use purple.1391

Step 1, this is going to be the first step of lytic.1401

Remember, the first step is attachment.1410

That is a bacteriophage, this is also known just as phage.1421

Sometimes you will hear T4T4 phage.1426

This is definitely a bacterium that I’m drawing, here is the host cell,1429

that bacteriophage that is docked in the outside, that is attachment.1433

Let us say that the host genome is yellow, that is that circular single chromosome that the bacterium has.1438

Onto step 2, there is the host, once again alien spaceship, that is actually a bacteriophage.1452

Here is where you have the viral DNA going in.1468

This is that entry that I told you about before.1473

After entry, we have step 3, this is replication.1483

This just remains here, this some kind of shell of a bacteriophage, protenacious shell, it is just there.1495

Eventually, it could just break down and dissolve into pieces.1504

It is useless at this point because now the really meaningful part that viral DNA has gone inside,1511

you are going to make lots of copies of that.1518

You are going to use the enzymes of this bacterium, RNA polymerase to make RNA from that DNA.1521

You are going to make protein parts.1529

Here are a bunch of capsids, tail fibers, the tails.1533

Not enough room in this drawing to write it.1541

But there is enough room in the actual host cell to make hundreds, if not a thousand copies of this bacteriophage and all its parts.1543

That is replication, next is assembly.1552

The assembly is, you are going to see what look like the little offspring of that virus that docked on the outside.1571

And more of course, but I do not have enough rom.1587

They have that little DNA in there, they are ready to go.1590

Finally step 5, busting out.1595

There, out of there, you get the picture.1617

You got there viral DNA.1624

We will say that the 4th one already left, it kind of head start.1627

Yes, this host cell will die in the process, too bad.1632

That is the lytic cycle.1637

Step 5 will eventually lead back to step 1, because these are all going to go other host cells nearby and do it all over again.1639

We are going to go to the purple arrows because there is a fork in the road here.1650

Once viral DNA enters, it actually could go this route.1654

This is going to be, we will call step 3.1660

I should do purple numbers for this one to differentiate.1663

This is that provirus stage.1667

We have got the host genome and then inserted in there is the viral stuff.1676

Like I said before, phosphate sugar base, that is the structure of DNA of every organism on earth, including viral DNA.1685

It can easily just kind of slip in, cut and paste itself in there.1694

The host, oftentimes, will not even knew.1700

The next stage, I’m going to do two little arrows to represent the fact that it is cell division.1707

It divides and you get that viral DNA being passed on.1720

From there, eventually at some point, step 5, that provirus gets released from all these daughter cells, of course.1734

However many were made, at some point, each of them can get stimulated chemically to have the provirus exit.1768

Once again, you are going to go back to step 3, eventually.1777

Back in the lytic cycle, so that the virus can do its thing, actually make a lot more copies of itself.1782

This is a very strategic thing, this lysogenic part of the viral cycle allows it to remain dormant or remain hidden,1790

kind of lay low until the time is right, and then back to the business.1798

Retroviruses, I have heard someone say like, oh my god that is so retro.1807

Maybe they are talking about a style of clothing or furniture, or something.1813

Retro means it was a style back in the day, and now you are bringing it back, you are trying to make it popular again.1819

Retro means backwards like it is blast from the past.1827

Retroviruses, this a good name for this kind of virus because they do something backwards compared to viruses that are not retro.1833

Typically, a DNA virus enters a host cell, makes RNA with host enzymes, and then vital parts are made.1842

That is tradition, that is what normal viruses do.1850

But a retrovirus does it backwards and that is the retro part of it.1852

It is an RNA virus, that is the genetic information that is naturally in virus, that makes DNA once the vile genome enters the host.1859

The virus has its own enzyme, reverse transcriptase.1868

What is transcription?1872

If you saw the RNA lesson, transcription is reading DNA to make RNA, that is transcription.1874

What will be the reverse of that, making DNA from RNA.1884

Reverse transcriptase is an enzyme, if its ends with ASE that is a big hint.1889

Reverse transcriptase is an enzyme that does reverse transcription.1894

It can actually take RNA and put together two sided DNA from it.1897

RNA will be the compliment to one side of the DNA, and then they just make the other side.1903

HIV is an example of a retrovirus.1907

Here is a computer generated image of what it looks like.1912

You have got RNA strands in here, that is the yellow stuff.1915

Reverse transcriptase, that is these two orange dots.1918

It is just part of the toolkit of this kind of virus.1923

The capsid, made of protein, is right here, there is a matrix around it.1926

With another envelope, a lipid membrane on the outside, with these little antigens pocking out from it.1931

You could see that these antigen parts have different designations or names.1938

This is retroviruses, part of the arsenal of the viruses, in terms of what they can do and how they do it.1946

HIV and AIDS, HIV stands for human immunodeficiency virus.1960

I have read about SIV, which is simian immunodeficiency virus which means it would impact other primates other than us.1967

HIV is our version of this but you can see, comparable or analogous viruses in other primates.1977

Like I told you earlier in the lesson, the theory is that HIV that came into us, originated in chimpanzees.1985

Transmission of HIV can happen through blood or sexually transmitted fluids.1992

The most common ways that people get it is having unprotected sex with somebody that has HIV.1997

Even having protected sex, sometimes contraceptive devices are not 100% effective.2004

Statistically, there is no contraceptive device that is 100% effective all the time.2010

Having contact with a person with HIV has risks to it, that means sexual contact.2017

It can also happen through blood, sharing tattoo needles which is rarely done.2025

But also sharing a needle for drugs can get it from one person to another.2031

Also, the other unfortunate part that is actually no fault of the recipient is, sometimes, rarely,2037

it can happen through blood transfusions.2045

When I donated blood in the past, I know that the organizations that accept the blood,2049

they do everything they can to make sure that, that person does not have HIV, they do lots of tests.2053

Occasionally, every once in a while, it happens where the donor actually end up giving it to the recipient.2060

Also, it is very common for people to know this know, I just want to state that,2068

you cannot get HIV through saliva and not by touching someone.2076

Specially, in the 80’s and early 90’s, I recall people having some ridiculous view points about HIV.2082

It is because they were not educated about it, they really did not know otherwise.2089

But trust me, kissing someone with HIV is not going to pass it to you.2095

The virus infects helper T cells, this is a class of a white blood cells.2102

Helper T cells, the reason why when you get a cold, when you get pneumonia,2106

when you get different viral infections, they last just a short while.2112

The cold will last a few days, the flu will last 1 or 2 weeks.2118

Why does it go away?2122

You can thank your white blood cells for kicking the viruses butt, and helper T cells are a big part of that.2123

Unfortunately, it infects those very cells that help you work against viruses and help you get better from an illness.2130

When someone contracts HIV and that retrovirus starts invading these T cells and going to more T cells over time,2141

eventually, it can get to the point where AIDS develops.2150

There are plenty of drugs now, these drug cocktails in combination that make it so that,2154

it really prolongs the period of time for a person with HIV, whether or not they are going to get AIDS.2159

A good example would be Magic Johnson.2166

People these days who get HIV, there are lots of options, there are lots of ways that drugs can help it,2169

kind of not spread to the body as quick.2177

You can really make your life last a lot longer.2179

Eventually, what can happen is AIDS develops from HIV.2183

AIDS is acquired immune deficiency syndrome, that gets to the point where2187

so many of your white blood cells have been compromised,2192

that you can no longer fight off infections that typically are harmless, long term to the average healthy person.2196

AIDS results when you cannot fight off the cold, you cannot survive the flu,2207

even chickenpox could kill someone with AIDS.2214

That patient can no longer fend off infections, that is the point where it can definitely be a fatal case.2218

Smallpox, this is one of the most harmful viral diseases in human history.2227

If you are thinking of the black plague, the bubonic plague, that is actually bacterial.2233

There are plenty of other harmful viruses.2238

HIV, yes that is a harmful virus, it is a very virulent virus meaning harmful.2242

Ebola is a very harmful virus.2247

In terms of the hundreds and hundreds of years that this existed, really thousands of years that2249

this existed in human history and how many lives it took, and how widespread it got, smallpox was a big deal.2257

This is actually a drawing from the 1500’s, depicting what happened to the Aztec people upon Europeans arriving there.2263

A little bit of history, 243 BCE stands for before the common era, smallpox epidemic in China,2273

lots of people died from this epidemic at that point in time.2281

Flash forward, over a thousand years later and it is the common era also known as AD,2286

a hermit in China introduces a mild case in humans to build immunity.2291

This is a very early example of immunization, kind of having like a vaccination in a sense.2295

This particular individual actually helped a lot of Chinese people,2302

to the point where they would not get sick from smallpox which is a great step.2308

1519, just approximately 500 years ago, invading conquistadors spread smallpox to Mexico, decimating the Aztecs.2314

Smallpox, at that time, was found in the old world, we can call the Americas the new world, at that point in time.2329

It was one of those diseases that people in Europe, those populations, over thousands of years have been exposed to.2339

Some people would survive it.2348

It is one of those cases where the Aztec people and people in the new world, this was a disease,2351

this was a virus that was so foreign to them that it hit them so hard, and very quickly the population was decimated.2357

Sadly, it helped in Cortez and those European conquistadors taking over that population.2366

It really helped their invasion.2373

The Aztec peoples, the majority of them were affected by smallpox.2375

1796, almost 300 years later, Edward Jenner developed vaccines.2383

The first vaccination of smallpox, first official vaccine, that could be given to many people.2390

We can thank Jenner for that.2397

Flash forward to the 20th century, the Worldwide Health Organization adopts a plan to eradicate it.2400

The World Health Organization, they thought that this is something that we can actually get rid off.2408

We have the science, we have the medicine to be able to actually wipe this off the face of the earth.2413

A plan was made to do that, and amazingly within 5 years time, 1977, the last reported case was known in Somalia.2420

Since that time, we have not seen smallpox.2429

Now chances are smallpox is kept somewhere on earth, a sample of it is probably locked away in some lab,2433

maybe in multiple places.2443

The hope is that humans will never be exposed to that ever again.2446

At this point, the human population, it is been awhile since we have been exposed.2451

If it was unleashed, that would be a form of bioterrorism.2458

It would be something that will really take the human immune system by surprise.2462

Let us hope that does not happen.2469

As time goes on, we get so many great advancements where we can come up with vaccines and defeat viruses.2470

Make it where we use our medicine and our abilities to conquer that virus, so that it does not harm us.2478

Viruses, they will continue to evolve and there are always be something that can harm our species.2486

Prions are infectious proteins that damage the nervous system overtime.2493

These are not technically viruses, but I’m grouping them into the virus lesson because they are smaller but still a protein thing.2497

Remember, viruses have that protein envelope with genetic information inside of it.2507

Prions, they do not have DNA and RNA, they are just misshaped proteins that cause transmittable spongiform encephalopathy.2512

What was that mean?2523

It means that these proteins, when they get into the nervous system, they cause degeneration of your neurons,2524

to the point where it does lead to death, eventually.2532

Mad cow disease in cattle, when these prions, a certain class of them, get inside of the brain of a cow.2536

They named it mad cow because before the cow dies, it starts acting kind of crazy.2545

It goes mad because of these prions causing that damage over time.2551

If mad cow disease gets into humans, it is known as Creutzfeldt-Jakob disease which is abbreviated as CJD.2556

The way that it gets from cows to humans, this is just a theory,2567

there are many theories on how it happens but this is a widely accepted one.2571

If beef is being taken off of a dead cow, it is being butchered.2575

If the butcher who was actually getting that meat off of the carcass accidentally severs the brain casing2581

or the spinal cord casing, the prion could get out of that region into the muscle tissue.2589

When that is sold to market, regardless of how much you cook the muscle tissue,2596

regardless of how well done you make that meat, the prion lasts, it will not go away.2600

If you eat that contaminated beef, it can end up inside of your nervous system.2606

There is no cure right now.2612

Scrapie is the version of this prion disorder in sheep.2615

Like I said, there is no known cure.2621

Once these infectious proteins are in your body, they cause gradual degeneration of tissue.2623

Think of it this way, over time, they cause normal proteins to mutate.2628

These prions bump into the proteins of your nervous tissue, it is this kind of negative domino effect.2632

Over time, it gets more widespread.2641

The brain tissue, if you were to look at an individual that has CJD or an animal that has this spongiform encephalopathy,2643

the brain tissue gradually atrophies over time because of this negative prion effect.2653

That is prions, thank you for watching www.educator.com.2662

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