lecture two: prokaryotes Flashcards

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1
Q

prokaryotes were found

A

4 billion years ago

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2
Q

domiant prokaryotes are found in

A
  • sea vents
  • hot springs
  • under ice
  • desert
  • europa ( moon)
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3
Q

cellular orginization of prokaryotes

A
  • smaller than eukaryotes- about 1-10 micrometers
  • simpler than eukaryotes
  • lack membrane bound organelles
  • one big compartment
  • no nucleus, has nucleiod region
  • plasma membran is folded inward, contains enzymes for respiration & photosynthesis
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4
Q

functions for cell well

A
  • protects cell
  • maintains shape
  • prevents bursting
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5
Q

peptidoglycan

A
  • carb polymer
  • charecterisitc of domain bacteria only
    can identify based on cell wall
  • not found in archea
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6
Q

two types of bacertial cell walls

A
  • based on gram stain
  • crystal violet -> purple
  • safranin - pink
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7
Q

gram positive bacteria

A
  • thick wall, primarly peptidoglycan
  • remains crystal violet
  • doesnt see safranin
  • stains purple
  • penicillin interferes w peptidoglycan sysnthesis
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8
Q

gram negative bacteria

A

thin peptidoglycan inner layer, lipoplysacchride outer layer

  • does not remain crystal violet
  • safranin visible
  • stains pink
  • gram - more oftern likely to cause serious diease
  • lipo can cause fever
  • important to differentiate to treat infections correctly
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9
Q

taxis

A
  • directed movement in respoce to stimulis

- 50% of prokarotes are capapble of stimulus

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10
Q

what is the flagella

A

most common motility structure in prokaryotes

convergent evolution - analogous strucutre in different domains

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11
Q

flagella is found in

A

bacteria archea, eukaryotes

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12
Q

functions of flagllum

A
  • H+ pumps across plastid membrane by ETC
  • forms gradient H+ diffuse through motor
  • E from diffusion turns motor
  • proton motive force ( respiration
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13
Q

requirement for evolution

A
  • sexual reproduction - recombination - genetic diversity
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14
Q

example of rapid reproduction and mutation

A
  • E.coli in human intestine
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15
Q

significance of rapid mutations

A
  • mutations rare on per gene basis
  • short generations & large populations - increase genetic variation
  • high diversity - rapid evolution - better adapted
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16
Q

epic experiment

A
  • rapid mutations
  • 12 e.coli populations, glucose runs out
  • relative fitness in increased, having more mutations is more beneficial in the context
17
Q

genetic recombination

A

combining DNA from 2 sources

18
Q

transformation genetic recombination

A

prokaryotic cells take up foreign DNA from environment ( Griffiths experiment)

19
Q

transduction genetic recombination

A

phages transfer prokaryotic genes from one cell to another ( virus mediated)

20
Q

conjunction genetic recombination

A
  • direct transfer of genetic materials from one cell to another, usually same species
  • involved fertility factor 9F) - often a plasmid
    F+ cell = cell that has F cell ( donor cell)
  • required for production of pili “ appendage for DNA transfer
  • can transfer part of chromosome as well
21
Q

genetic diversity

A
  • prokaryotes are asexual
  • reproduce rapidly
  • have mechanisms for recombination - high genetic diversity
22
Q

metabolic diversity needs

A

energy and carbon

23
Q

metabolic energy sources

A
  • phototrophs: E from light ( plants, green algae)

- chemotrophs: E from chemicals (humans)

24
Q

metabolic carbon sources

A
  • autotrophs: only need CO2, or other inorganic C ( can do carbon fixation)
    • heterotrophs: required organic C , eg. glucose
25
Q

key process of prokaryotic diversity

A

horizontal gene transfer

26
Q

groups of bacterial diversity

A
  • chlamydia
  • spirochetes
  • cyanobacteria
  • gram positive b
27
Q

probacteria

A
  • large & diverse- 5 groups ( alpha,beta, gamma, delta & epsilsion
28
Q

extremophiles live in

A

extreme environments

29
Q

halophiles

A

high saline environments

30
Q

thermophile/ hyperthermophiles

A

hot environemts