Chapter 27: Bacteria & Archaea Flashcards

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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
Q

Chp 27

Chemoheterotroph

A
  • enerygy souce: light
  • carboon osurce: organic compounds
  • types of organisms: many prokaryotes
26
Q

Chp 27

role of oxygen in metabolism

A
  • 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
Q

Chp 27

nitrogen metabolism

A
  • prokaryotes can metabolize nitrogen via nitrogen fixation
  • converting atmospheric nitrogen to ammonia
28
Q

Chp 27

metabolic cooperation

A
  • 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
29
Q

Chp 27

bacteria

A

diverse nutrional types are represented among bacteria

30
Q

Chp 27

proeobacteria

A
  • gram negative
  • include photoautotrophs, chemoautotrophs, & heterotrophs
  • some anaerobic & others aerobic
  • 5 subgroups
31
Q

Chp 27

Alpha proteobacteria

A
  • closely associated w/ eukaryotic hosts
  • hypothesize that mitochondria evolved from aerobic alpha via endosymbiosis
32
Q

Chp 27

Beta proteobacteria

A
  • nutritionally diverse
  • other members include aquatic species & pathogens
33
Q

Chp 27

Gamma proteobacteria

A
  • include sulfur bacteria
  • some are pathogenic
  • some can reside in the intestines of many mammals
    *ex: salmonella, escherichia coil
34
Q

Chp 27

Delta proteobacteria

A
  • ex: myxobacteria prodouces drought-resistant myxospores
  • ex: bdellovibrios: mount high speed attacks on other bacteria
35
Q

Chp 27

Epsilon proteobacteria

A
  • most are pathogenic
  • ex: campylobacter which causes blood poisoning & helopcobacter pylori which causes stomach ulcers
36
Q

Chp 27

Chlamydias

A
  • parasites that live within animal cells
37
Q

Chp 27

Spirochetes

A
  • helical gram-negative heterotrops
  • some are parasites which cause syphilis and lyme disease
38
Q

Chp 27

Cyanobacteria

A
  • gram negative photoautotrophs that make oxygen
  • plant chloroplasts via endosymbiois prob evolved from this
  • abundant components of freshwater & marine phytoplankton
39
Q

Chp 27

Archaea

A
  • 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
Q

Chp 27

Chemical recycling

A
  • prokaryotes recycle chemical elements between components of the environment
  • decomposers: some chemoheterotrophic; break down dead organisms & waste products
41
Q

Chp 27

Ecological interactions

A
  • 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
Q

Chp 27

Mutalistic bacteria

A

they break down food that is undigested by human intestine

43
Q

Chp 27

pathogenic bacteria

A

bacteria cause about half of all human diseases

44
Q

Chp 27

exotoxins vs endotoxins

A
  • exotoxin: secreted and cause disease; cell purposely release this to harm/protect cell
  • endotoxin: released only when bacteria die and cell wall breaks down