Paige Lake
General Biology II
Due date: N/A
General Biology II
Virology & Prokaryotes 🔎
☆ Virology
☆ ↪️ SEQ Evolution by Natural Selection
1. Heritable Variation in Traits (must be genetic variation to begin with)
↓
2. Environmental Pressure (e.g. limited resources, predators)
↓
3. Differential Survival & Reproduction ( → survival of the fittest)
↓
4. Individuals with Beneficial Traits Survive and Reproduce More
↓
5. Frequency of Beneficial Traits Increases in Population (Allele Frequency Changes)
↓
6. Evolution Occurs (Over Generations)
☆ 🌳 Parts of a Phylogenetic Tree (Interpret a Phylogeny)
Root
|
|
------------------
| |
| |
Node Basal Taxon
|
|
------------------
| |
| |
Node Sister Taxa 1
|
|
------------------
| |
| |
, ^Sister Taxa 2 Node (Polytomy)
|
|
----------------------
| | |
| | |
Monophyletic Paraphyletic Polyphyletic
Group Group Group
☆ PSC (Phylogenetic species concept): The smallest group of organisms that share an evolutionary history.
☆ Dichotomies: Two-way branch points in a phylogenetic tree.
☆ Branch points / nodes: Represent divergence from a common ancestor.
☆ Sister taxa: Two taxa sharing an immediate common ancestor.
☆ Basal taxon: Diverges early in evolutionary history.
☆ Polytomy: Branch where more than two groups emerge, indicating uncertainty.
☆ Monophyletic: common ancestor + all descendants.
☆ Paraphyletic: common ancestor + some (not all) descendants.
☆ Polyphyletic: no common ancestor.
☆ ↪️ SEQ General Viral Replication Cycle (Lytic)
1. Virus Binds to Host Cell’s Capsid (protein coat; made of capsomeres – determines morphology & needed for viral
attachment to host cell)
↓
2. Entry of Viral Genome (injection, endocytosis, etc.)
↓
3. Replication of Genome & Transcription of Viral Genes
↓
4. Assembly of New Viruses
↓
5. Exit from Host Cell (lysis or budding)
↓
6. Infection of New Cells
☆ 📊 CC Lytic & Lysogenic Cycles
, Feature Lytic Cycle Lysogenic Cycle
Host Cell Fate Destroyed (Lysed) Survives (virus [bacteriophage]
integrates into host bacterial
chromosome; replicates as host
replicates – can remain in organism as
long as it’s cells stay healthy)
Transmission Horizontal (Host to Host) Vertical (passed to daughter cells; host
to offspring)
Viral DNA Status Active replication immediately after Integrates into host genome (becomes
entry. prophage - bacteriophage that is
integrated into the genetic material of
the host)
Virus Type Virulent phages (phages that are only Temperate phages (can do both lytic
capable of the lytic cycle) & lysogenic)
Conditions Triggered by stress, poor host Preferred when the host is healthy.
conditions.
Example T4 bacteriophage Lambda phage (λ)
☆ Prokaryotes
☆ 📊 CC Prokaryotic & Eukaryotic Cells
Feature Prokaryotes Eukaryotes
Nucleus No Yes
Organelles No (no mitochondria, ER, etc.) Present (e.g. mitochondria, ER)
Cell Size Smaller (~1-10 micrometers) Larger (~10-100 micrometers)
Cell Wall Often (w/ peptidoglycan in bacteria) In plants/fungi (cellulose/chitin)
- Gram + = thick
peptidoglycan wall; stains
purple in gram stain; less
likely to cause serious
disease.
- Gram - = thin
peptidoglycan wall; stains
pink in gram stain; more
likely to cause serious
, disease.
Cell Type Unicellular ONLY Unicellular or multicellular
Ribosomes Yes (smaller) Yes (larger)
Flagellum Yes (for locomotion) Yes (e.g. sperm cells)
H+ pumped out across Plasma
Membrane (PM) by ETC.
↓
Proton gradient created (more H+
outside).
↓
Energy stored in proton gradient
(concentration & charge difference).
↓
Protons diffuse into cell through
motor.
↓
Protons flow through Mot protein
Complex (at flagellum base).
↓
Proton flow releases energy.
↓
Energy drives rotor (part of flagellar
motor).
↓
Rotor turns.
↓
Hook turns (connects motor to
filament, transmits force).
↓
Filament rotates (long structure
attached to hook).
↓
Bacterium propelled forward.
DNA Structure Circular DNA Linear Chromosomes
Modes of Reproduction Asexual (binary fission) Sexual/asexual
Domains Bacteria, Archaea Eukarya
☆ ↪️ SEQ Prokaryotes Reproduction
General Biology II
Due date: N/A
General Biology II
Virology & Prokaryotes 🔎
☆ Virology
☆ ↪️ SEQ Evolution by Natural Selection
1. Heritable Variation in Traits (must be genetic variation to begin with)
↓
2. Environmental Pressure (e.g. limited resources, predators)
↓
3. Differential Survival & Reproduction ( → survival of the fittest)
↓
4. Individuals with Beneficial Traits Survive and Reproduce More
↓
5. Frequency of Beneficial Traits Increases in Population (Allele Frequency Changes)
↓
6. Evolution Occurs (Over Generations)
☆ 🌳 Parts of a Phylogenetic Tree (Interpret a Phylogeny)
Root
|
|
------------------
| |
| |
Node Basal Taxon
|
|
------------------
| |
| |
Node Sister Taxa 1
|
|
------------------
| |
| |
, ^Sister Taxa 2 Node (Polytomy)
|
|
----------------------
| | |
| | |
Monophyletic Paraphyletic Polyphyletic
Group Group Group
☆ PSC (Phylogenetic species concept): The smallest group of organisms that share an evolutionary history.
☆ Dichotomies: Two-way branch points in a phylogenetic tree.
☆ Branch points / nodes: Represent divergence from a common ancestor.
☆ Sister taxa: Two taxa sharing an immediate common ancestor.
☆ Basal taxon: Diverges early in evolutionary history.
☆ Polytomy: Branch where more than two groups emerge, indicating uncertainty.
☆ Monophyletic: common ancestor + all descendants.
☆ Paraphyletic: common ancestor + some (not all) descendants.
☆ Polyphyletic: no common ancestor.
☆ ↪️ SEQ General Viral Replication Cycle (Lytic)
1. Virus Binds to Host Cell’s Capsid (protein coat; made of capsomeres – determines morphology & needed for viral
attachment to host cell)
↓
2. Entry of Viral Genome (injection, endocytosis, etc.)
↓
3. Replication of Genome & Transcription of Viral Genes
↓
4. Assembly of New Viruses
↓
5. Exit from Host Cell (lysis or budding)
↓
6. Infection of New Cells
☆ 📊 CC Lytic & Lysogenic Cycles
, Feature Lytic Cycle Lysogenic Cycle
Host Cell Fate Destroyed (Lysed) Survives (virus [bacteriophage]
integrates into host bacterial
chromosome; replicates as host
replicates – can remain in organism as
long as it’s cells stay healthy)
Transmission Horizontal (Host to Host) Vertical (passed to daughter cells; host
to offspring)
Viral DNA Status Active replication immediately after Integrates into host genome (becomes
entry. prophage - bacteriophage that is
integrated into the genetic material of
the host)
Virus Type Virulent phages (phages that are only Temperate phages (can do both lytic
capable of the lytic cycle) & lysogenic)
Conditions Triggered by stress, poor host Preferred when the host is healthy.
conditions.
Example T4 bacteriophage Lambda phage (λ)
☆ Prokaryotes
☆ 📊 CC Prokaryotic & Eukaryotic Cells
Feature Prokaryotes Eukaryotes
Nucleus No Yes
Organelles No (no mitochondria, ER, etc.) Present (e.g. mitochondria, ER)
Cell Size Smaller (~1-10 micrometers) Larger (~10-100 micrometers)
Cell Wall Often (w/ peptidoglycan in bacteria) In plants/fungi (cellulose/chitin)
- Gram + = thick
peptidoglycan wall; stains
purple in gram stain; less
likely to cause serious
disease.
- Gram - = thin
peptidoglycan wall; stains
pink in gram stain; more
likely to cause serious
, disease.
Cell Type Unicellular ONLY Unicellular or multicellular
Ribosomes Yes (smaller) Yes (larger)
Flagellum Yes (for locomotion) Yes (e.g. sperm cells)
H+ pumped out across Plasma
Membrane (PM) by ETC.
↓
Proton gradient created (more H+
outside).
↓
Energy stored in proton gradient
(concentration & charge difference).
↓
Protons diffuse into cell through
motor.
↓
Protons flow through Mot protein
Complex (at flagellum base).
↓
Proton flow releases energy.
↓
Energy drives rotor (part of flagellar
motor).
↓
Rotor turns.
↓
Hook turns (connects motor to
filament, transmits force).
↓
Filament rotates (long structure
attached to hook).
↓
Bacterium propelled forward.
DNA Structure Circular DNA Linear Chromosomes
Modes of Reproduction Asexual (binary fission) Sexual/asexual
Domains Bacteria, Archaea Eukarya
☆ ↪️ SEQ Prokaryotes Reproduction
