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Biology 108 > Lecture 10 Prokaryotes > Flashcards

Lecture 10 Prokaryotes Flashcards

0
Q

where can prokaryotes thrive?

A

almost anywhere

-includes very acidic places, high salinity, extreme temperatures

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1
Q

what are the two domains that are considered prokaryotes?

A

bacteria and archaea

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2
Q

what are seven characteristics of prokaryotes?

A
  1. no nucleus
  2. plasmids
  3. lack compartmentalization
  4. prok < euk in size
  5. cell wall – peptidoglycan
  6. 1/2 of prok are motile
  7. reproduction and gene transfer in several forms
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3
Q

how is genetic material arranged in prokaryotes?

and how much is there?

A
  • diffused, circular ring of DNA not enclosed by a membrane
  • located in nucleoid region
  • prok genome has less DNA than euk genome
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4
Q

what are plasmids?

A

small rings of DNA containing ‘extra’ genes

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5
Q

what is peptidoglycan?

A

a network of sugar polymers cross-linked by polypeptides

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6
Q

what is the function of the cell wall in prokaryotes? (3)

A
  • maintains cell shape
  • protects the cell
  • prevents bursting in hypertonic environments
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7
Q

what are the two types of bacterial cell wall?

A
  • gram +

- gram -

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8
Q

what is a gram + wall?

A
  • simpler bacterial cell wall with a lot of external facing peptidoglycan
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9
Q

what is a gram - wall?

A

a bacterial cell wall that has a lipopolysaccharide layer outside of the cell wall which doesn’t absorb the gram stain readily

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10
Q

why are bacteria with gram - cell walls usually more pathogenic than gram + bacteria? (2)

A

can contain toxins and can resist antibiotics

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11
Q

what are 3 cell-surface structures of bacteria?

A
  • capsule
  • fibrae
  • pili / sex pili
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12
Q

what is a capsule?

A

a polysaccharide or protein layer that covers many prokaryotes

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13
Q

what is a fimbrae?

what does it allow bacteria to do (2) ?

A

adaptation that allows the bacteria to stick to substrates or other individuals in a colony

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14
Q

how do most bacteria move?

A

using flagella scattered about the surface of the bacteria or concentrated at one or both ends

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15
Q

how are the flagella of bacteria, archaea, and eukarya diffferent?

A

composed of different proteins and most likely evolved independently

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16
Q

what is taxes/taxis?

A

the ability to move toward or away from a stimulus

ex: phototaxis – movement towards light

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17
Q

what form does bacterial reproduction NOT take

A

mitosis/meiosis

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18
Q

how do bacteria reproduce quickly

A

using binary fission – depends on environment

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19
Q

what are 3 factors that contribute to bacterial genetic variation

A
  • rapid reproduction
  • mutation
  • genetic recombination
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20
Q

how is mutation a factor for genetic variation (despite that mutation rates of binary fission is very low)

A

mutations occur rapidly in a population because of rapid reproduction

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21
Q

how is prokaryotic DNA from different individuals brought together? (3)

A
  • transformation
  • transduction
  • conjugation
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22
Q

what is transformation?

A

the uptake of foreign DNA from surroundings

ex: naked DNA from dead bacteria

23
Q

what is transduction?

A

movement of prokaryotic genes between bateria by bacteriophages – usually a mistake on phage’s part

24
Q

what is a bacteriophage?

A

a virus that infects bacteria

25
Q

what is conjugation? (3)

A
  • a process where genetic material is transferred between an donor cell to a recipient cell via PILUS
  • unidirectional
  • plasmids are often transferred
26
Q

by which process are plasmids often transferred?

A

conjugation

27
Q

what is metabolism?

A

chemical pathways used by living organisms to build up molecules

28
Q

compare anabolism vs catabolism

A

catabolism is the breakdown of molecules to release energy –think catastrophy
anabolism is the breakdown of molecules to release energy

29
Q

what are the four ways to catagorize prokaryotes by how they obtain energy and carbon?

A
  • phototrophs
  • chemotrophs
  • autotrophs
  • heterotrophs
30
Q

what are phototrophs?

A

organisms that obtain energy from light

31
Q

what are chemotrophs?

A

organisms that obtain energy from chemicals (usually inorganic)

32
Q

what are autotrophs?

A

organisms that use CO2 as a carbon source

33
Q

what are heterotrophs?

A

organisms that use organic nutrients to make organic compounds – often have to consume things

34
Q

what are the two types of prok autotrophs?

A
  • chemoautotrophs

- photoautotrophs

35
Q

what are the two types of prok hetertrophs?

A
  • photoheterotrophs

- chemoheterotrophs

36
Q

what do archaea lack in their cell wall?

A

peptidoglycan

37
Q

what kind of philes are archaea?

A

extremophiles

38
Q

how do archaea respond to antibiotice that inhibit eubacterial growth?

A

they DON’T

39
Q

what are three types of archaea covered in this course?

A
  • methanogens: live in O2 free environments
  • halophiles: very salty environments
  • thermophiles: very hot habitats
40
Q

what are four characteristics of eubacteria?

A

diverse, numerous, live almost everywhere, can be pathogenic or have positive interactions w/ humans

41
Q

what are the 5 major clades of bacteria?

A
  • proteobacteria
  • chlamydias
  • spirochaetes
  • cyanobacteria
  • “Gram +” bacteria
42
Q

what are proteobacteria?

A
  • large and metabolically diverse group of gram neg. bacteria
  • 5 sub linages
  • two examples: Rhizobium spp & E. coli
43
Q

what is the proteobacteria Rhizobium spp.?

what relationship does it have with plants?

A
  • live in root nodules of leguminous roots

- mutualistic–fix atm. nigtogen to make it available for the host plant to use, plant gives carbohydrates in return

44
Q

what is the proteobacteria E. coli? (5)

A
  • resides in many mammal intestines
  • not normally pathogenic
  • aids in digestion
  • synthesis of vitamins & other nutrients
  • some are toxic
45
Q

what are chlamydias?

what do the NOT have in their cell wall?

A
  • parasites only living within animal cells
  • no peptidoglycan in cell walls
  • ex: chlamydia trachomatis - common human STD, blindness in newborns
46
Q

what are spirochaetes?

A
  • long helical heterotrophic bacteria that swim by spiralling
  • many free-living
  • NASTY parasitic bacteria
  • ex: syphilis & Lyme disease (ticks)
47
Q

what are cyanobacteria/blue-green algae?

A
  • only prokaryotes that produce oxygen via photoautrophy

- often benignt, but some have toxins that impair liver fxns or act as neurotoxins

48
Q

where are plant chloroplasts thought to evolve from?

A

cynanobacteria via endosymbiosis

49
Q

what is the “Gram +” bacteria clade?

A
  • ONLY group with GRAM + bacteria (but also includes gram - taxa …?…)
  • very important decomposers in soil
  • source of many antibiotics like streptomycin
  • and mycoplasmas – smallest known cells
  • and clostridium botulinum – botulism
  • and bacillus anthracis – anthrax – that can enter resistant endospore state
50
Q

what is the importance of prokaryotes?

A
  • producers of O2 and fixers of N
  • major roles in recycling of chemical elements between living and non-living
  • ex: chemoheterotrophic prok that are decomposers can increase availability of N, P and K for plants
51
Q

what is symbiosis?

A

ecological relationship between two species that live in close contact specifically a larger host + a smaller symbiont

52
Q

what are 3 types of symbiotic relationships

A
  • mutualism: both benefit, ex methanogens in cow stomach, Rhizobium
  • commensalism: one benefits, other is neither harmed nor benefits
  • parasitism: parasite harms but doesn’t kill host (maybe eventually it will…)
53
Q

what are parasites that cause disease called?

A

pathogens

54
Q

what is the economic importance of prok?

A
  • food production
  • sewage treatment & bioremediation (decomposers)
  • production of vitamins, antibiotics, hormones, biofuels
  • ex Thermus aquaticus “taq” – used in PCR

Biology 108 (27 decks)

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