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19 and 27: Viruses, Bacteria, and Archaea - Coggle Diagram
19 and 27: Viruses, Bacteria, and Archaea
Chapter 27: Bacteria + Archaea
Nutritional + Metabolic Adaptations
Greater diversity than eukaryotes
Includes 4 modes
chemoautotrophy
inorganic chemicals as source; unique to prokaryotes
photoheterotrophy
light as source, requires 1+ organic molecule to make organic compounds
photoautotrophy
Light as source; photosynthesis
chemoheterotrophy
organic compounds, requires 1+ organic molecule to make organic compounds
Aerobes vs anaerobes
Obligate Aerobes
Require oxygen
Facultative anaerobes
Survive with or w/out oxygen
Obligate anaerobes
Harmed by oxygen
Can also metabolize nitrogen
In many forms
Example: nitrogen fixation
nitrogen from atmosphere converted to ammonia
Can cooperate metabolically (biofilms)
Diverse Lineages
Bacteria
Types
Spirochetes
helical, gram-negative
example = borrelia burgdorferi causes lyme disease
Cyanobacteria
gram-negative, photoautotrophs
plant-like
Chlamydias
Parasites
Only survive in animal cells
Gram-positive bacteria
most are decomposers in soil
Proteobacteria
clade of gram-negative bacteria
includes photoautotrophs, chemoautotrophs, heterotrophs
Archaea
1st were extremophiles
extremophiles = live in extreme conditions
extreme halophiles = live in highly saline environments
extreme thermophiles = live in very hot conditions
not all archaea = extremophiles
example = methanogens
methanogens = release methane as by-product of obtaining energy
some = extremophiles, some live in swamps/marshes
Prokaryotic Diversity
Archaea more closely resemble eukaryotes
Genomes of prokaryotes can be studied from environmental samples
"genetic prospecting"
Parts of genomes can be "mosaics" of genes from other species
Very diverse
Reproduction, Mutation, and Recombination
Reproduce + evolve rapidly
Diversity can be due to recombination
transduction
phages carry genes from one host cell to another
conjugation
DNA transferred between 2 prokaryotic cells via temporary joining
Connects via sex pilus
Ability to perform conjugation due to F-factor
F factor = piece of DNA required for pili production, etc.
2 more items...
transformation
genotype / phenotype altered by uptake of foreign DNA
Prokaryotic role in Biosphere
Chemical Recycling
Prokaryotes have major role
Example: some chemoheterotrophic prokaryotes = decomposers
Decomposer = breaks down dead organisms to obtain nutrients
Ecological Interactions
Symbiosis = 2 species live in close contact w/ each other
larger = host
smaller = symbiont
mutualism = prokaryote + host mutually benefit each other
Other interactions = commensalism, parasitism
Commensalism = one benefits, other not harmed or helped
Parasitism = parasite feeds of components of host
pathogens = parasites that cause disease
Structural + Functional Adaptations
Prokaryotes = make up domains bacteria + archaea
Most unicellular, vary in shape
Bacillus
Rod-shaped
Spiral-shaped
Coccus
Spherical
Structure
Cell wall
Contain peptidoglycan
Gram negative
less peptidoglycan in cell wall, more complex
Pink on gram stain
Gram positive
Simpler cell wall, has more peptidoglycan
Purple on gram stain
Cell wall sometimes surrounded by layer of polysaccharide/protein
Structured/defined = capsule
Undefined = slime layer
Endospores = resistant cells
Formed when lacking water/nutrition
Able to survive dormant for centuries
Fimbrae = hairlike structures used for sticking to other things
Shorter/more numerous than pili
Prokaryotic impacts on humans
Not all prokaryotes harmful
Example = beneficial bacteria found in our bodies
pathogenic bacteria = cause diseases
typically via exotoxins or endotoxins
Endotoxins = lipopolysaccharide components in membrane of gram-negative bacteria
Exotoxins = proteins secreted by some bacteria/organisms
resistance can/has evolved in bacteria
bioremediation = reducing pollution in soil, air, water w/ organisms
Prokaryotes can be used in bioremediation
Examples
Cleaning up oil spills, decomposing organic matter in sewage
Chapter 19: VIruses
Replication
Can only replicate w/in a host cell
bacteriophages = viruses that infect bacteria
Replicate via lytic or lysogenic cycle
Lytic
New viruses created rapidly within host cell
Host cell eventually lyses (bursts)
Large amounts of new viruses released all together
Host cell usually killed
Lysogenic
Viral dna incorporated into cell's chromosome
Incorporated DNA = prophage
Prophage eventually exits chromosome to enter lytic cycle
Host range = number of organisms/species virus can infect
Retroviruses = have RNA genome
Use reverse transcriptase (enzyme) to copy RNA to DNA
DNA can integrate into host genome as a provirus
Example: HIV
Viruses and Prions
Vaccine = harmless derivative of pathogen
Injected to stimulate body's creation of defense against the harmful pathogen
Prion = infectious proteins in animals
Misfolded protein that induces other proteins to become misfolded
Causes brain diseases
Slow-acting
Nearly indestructible
Epidemic vs Pandemic
Pandemic = global outbreak of a disease
Example: COVID-19 pandemic
Emerging viral diseases = new outbreaks/infections of humans not seen before
Usually caused by expansion of host territory
Epidemic = widespread outbreak of a disease
Virus Structure
Viruses discovered in 1800s
Determined via filtering out larger bacteria
Virus = genetic material + proteins
DNA/RNA enclosed in capsid (protective, made of proteins)
May have a viral envelope derived from host cell membrane(s)
Can have single- or double-stranded DNA or RNA
Likely evolved after first cells
Potentially from packaged nucleic acid from said cells