Chapter 27: Bacteria & Archaea Flashcards

1
Q

Chp 27

Cell-Surface Structures

A
  • eukaryote cell wall is made out of cellulose/chitin
  • prokaryotic cell wall contains peptidoglycan (sugar polymers)
  • archaea caintain polysaccharides and lack peptidoglycan
  • Gram stain is used to classify bacteria by cell wall composition
  • Gram (+): large amount of peptidoglycan & gram (-): less peptidoglycan
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2
Q

Chp 27

Gram positive bacteria

A
  • include colony forming groups to decompose matter
  • include solitary species
  • mycoplasms lack cell walls
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3
Q

Chp 27

What is the capsule?

A
  • sticky outer layer of polysaccharide/protein present in some prokaryotes
  • allows adherence to substrate or other individuas
  • can shield pathogenic bacteria from the host immune system
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4
Q

Chp 27

What is an endospore?

A
  • they are metabolically inactive formed by many prokaryotes
  • can remain viable in harsh conditions for centuries
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5
Q

Chp 27

What is the difference between fimbriae and pili?

A
  • fimbriae: hairlike appendages that allow prokaryotes to stick to their substrate/individuals in a colony
  • Pili (sex pili): longer than fimbriae; allow prokaryotes to exchange DNA
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6
Q

Chp 27

Mobility

A
  • Taxis: The ability to move toward or away from a stimulus
  • Flagella are the most common strutures used by prokaryotes for movement
  • flagella of prokaryotes & eukaryotes differ in structure, etc…
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7
Q

Chp 27

Internal organization and DNA

A
  • prokaryotic cells lack complex compartmentalization
  • infoldings of the plasma membrane in these prokaryotic cells perform metabolic functions
  • most of the genome consists of a circular chromosome
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8
Q

Chp 27

Nucleoid

A
  • where chromosome is located
  • has no surrounding membrane
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9
Q

Chp 27

Plasmids

A
  • independtly replicating DNA found in typical prokaryotes
  • have smaller rings
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10
Q

Chp 27

Reproduction

A
  • prokaryotes reproduce by binary fission and can divide every 1-3 hrs
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11
Q

Chp 27

what are the key featires of prokaryote biology?

A
  • they are small
  • reproduce by binary fisiion
  • have short generation times
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12
Q

Chp 27

What three things contribute to prokaryotes’ genetic variation?

A
  • rapid reproduction
  • mutation
  • genetic recombination
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13
Q

Chp 27

Rapid reproduction and mutation

A
  • prokaryotes reproduce asexually
  • mutation rates are low but they accumulate rapidly (b/c generation times are short & populations are large)
  • their cells have rapid adaptation to environmental change meaning that are highly evolved
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14
Q

Chp 27

Genetic recombination

A
  • def: combining of DNA from 2 sources that contributes to diveristy
  • transformation, transduction, 7 conjugation facilitate this
  • horizontal gene transfer: movement of genes among individuals from different species
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15
Q

Chp 27

Transformation

A

when a prokaryotic cell takes up & incorporate foreign DNA from surrounding environment

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16
Q

Chp 27

transduction

A

movement of genes between bacteria by phages (bacteriophages - viruses that infect bacteria)
1. phage infects bacterial donor cell that carries A+ & B+ alleles
2. phage dna is replicated & phage proteins are made
3. fragment of dna w/ A+ allele is packages within a phage capsid
4. phage w/ A+ allele infects bacterial recipient cell
5. incorporation of phage DNA creates recombinant cell with A+ & B-

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17
Q

Chp 27

conjugation & plasmids

A
  • conjugation: process where genetic material is transferred between prokaryotic cells
  • the transferred DNA is often in the form of a plasmid
  • F factor (piece of DNA) required for production of pili
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18
Q

Chp 27

F factor as a plasmid

A
  • F plasmid: DNA donors during conjugations
  • Cells w/out f factor function as the recipient
  • f factor is transferable during conjugation
19
Q

Chp 27

F factor in the chromosome

A
  • cell with f factor in chromosome will be donot during conjugation
  • ^^^ called Hfr cells (high frequenct of recombination)
  • recipient becomes a recombinant bacterium with DNA from two different cells
20
Q

Chp 27

R plasmids and antibiotic resistance

A
  • r plasmids carry genes for antibiotic resistance
  • antibiotics dont kill bacteria with specific r plasmids
  • some r plasmids carry genes for resistance to multiple antibiotics
21
Q

Chp 27

how are prokaryotes categorized by how they obtain energy/carbon?

A
  • phototrophs obtain energy from light
  • chemotrophs obtain energy from chemicals
  • autotrophs require carbon dioxide as a carbon source
  • heterotrophs require organic nutrient to make organic compounds
22
Q

Chp 27

Photoautotroph

A
  • energy source: light
  • carbon source: CO2, HCO3, etc…
  • types of organisms: photosynthetic prokaryotes
23
Q

Chp 27

Chemoautotroph

A
  • energy source: inorganic chemicals
  • carbon source: CO2, HCO3, etc…
  • types of organisms: unique to certain prokaryotes
24
Q

Chp 27

Photoheterotroph

A
  • energy source: light
  • carbon source: organic compounds
  • types of organisms: unique to certain aquatic & salt-loving prokaryotes
25
# **Chp 27** Chemoheterotroph
* enerygy souce: light * carboon osurce: organic compounds * types of organisms: many prokaryotes
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# **Chp 27** role of oxygen in metabolism
* obligate aerobes: require O2 for cellular respiration * obligate anaerobes: poisoned by O2 and live by fermentation * facultative anaerobes: can/cant use O2 depending on presence of O2
27
# **Chp 27** nitrogen metabolism
* prokaryotes can metabolize nitrogen via nitrogen fixation * converting atmospheric nitrogen to ammonia
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# **Chp 27** metabolic cooperation
* allows prokaryotes to use environmental resources they could not use as individual cells * heterocysts: nitrogen-fixing cells * biofilms: surface coaitng colonies where metabolic cooperation between different proakryotes take place
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# **Chp 27** bacteria
diverse nutrional types are represented among bacteria
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# **Chp 27** proeobacteria
* gram negative * include photoautotrophs, chemoautotrophs, & heterotrophs * some anaerobic & others aerobic * 5 subgroups
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# **Chp 27** Alpha proteobacteria
* closely associated w/ eukaryotic hosts * hypothesize that mitochondria evolved from aerobic alpha via endosymbiosis
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# **Chp 27** Beta proteobacteria
* nutritionally diverse * other members include aquatic species & pathogens
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# **Chp 27** Gamma proteobacteria
* include sulfur bacteria * some are pathogenic * some can reside in the intestines of many mammals *ex: salmonella, escherichia coil
34
# **Chp 27** Delta proteobacteria
* ex: myxobacteria prodouces drought-resistant myxospores * ex: bdellovibrios: mount high speed attacks on other bacteria
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# **Chp 27** Epsilon proteobacteria
* most are pathogenic * ex: *campylobacter* which causes blood poisoning & *helopcobacter pylori* which causes stomach ulcers
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# **Chp 27** Chlamydias
* parasites that live within animal cells
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# **Chp 27** Spirochetes
* helical gram-negative heterotrops * some are parasites which cause syphilis and lyme disease
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# **Chp 27** Cyanobacteria
* gram negative photoautotrophs that make oxygen * plant chloroplasts via endosymbiois prob evolved from this * abundant components of freshwater & marine phytoplankton
39
# **Chp 27** Archaea
* share certain traits w/ bacteri & other traits w/ eukaryotes * have many unique characteristics * extreme halophiles: live in highly saline environments * extreme thermophiles: trhive in very hot environments * mthanogens: live in swamps & marshes and produce methan as waste
40
# **Chp 27** Chemical recycling
* prokaryotes recycle chemical elements between components of the environment * decomposers: some chemoheterotrophic; break down dead organisms & waste products
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# **Chp 27** Ecological interactions
* symbiosis: two species live in close contact: a larger host & smaller symbiont * prokaryotes often do this with larger organisms * parasites that cause disease are called pathogens
42
# **Chp 27** Mutalistic bacteria
they break down food that is undigested by human intestine
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# **Chp 27** pathogenic bacteria
bacteria cause about half of all human diseases
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# **Chp 27** exotoxins vs endotoxins
* exotoxin: secreted and cause disease; cell purposely release this to harm/protect cell * endotoxin: released only when bacteria die and cell wall breaks down