Lecture 21 - Prokaryotes 1 Flashcards

1
Q

Where do prokaryotes thrive?

A
  • almost everywhere

- even too acidic, salty, cold , or hot for other organisms

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2
Q

Are prokaryotes macroscopic or microscopic?

A

microscopic

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3
Q

What are the two domains of prokaryotes?

A
  1. bacteria

2. archaea

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4
Q

What are the 3 elements of the tree of life?

A
  1. bacteria
  2. archaea
  3. eukaryotes
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5
Q

Archaea are more closely related to ______ than to ________

A

Eukaryotes, Bacteria

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6
Q

What were earth’s first organisms?

A

prokaryotes

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7
Q

Are prokaryotes uni or multicellular?

A

unicellular, but some species form colonies

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8
Q

How small are most prokaryotic cells?

A

0.5-5 micron

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9
Q

What are the 3 most common shapes of prokaryote cells?

A
  1. spheres (cocci
  2. rods (bacilli)
  3. spirals
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10
Q

What is trichodesmium?

A

colonial marine nitrogen-fixing cyanobacterium

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11
Q

What is the important feature of nearly all prokaryotic cells?

A

cell wall

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12
Q

What do cell walls do?

A
  • maintains cell shape
  • protects cell
  • prevents it from bursting in a hypotonic environment
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13
Q

What are eukaryote cell walls made of?

A
  • cellulose

- chitin

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14
Q

What are bacterial cell walls made of?

A

peptidoglycan

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15
Q

What is peptidoglycan?

A
  • network of sugar polymers

- cross-linked by polypeptides

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16
Q

What doe archaea contain? lack?

A
  • polysaccharides + proteins

- lack peptidoglycan

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17
Q

What is a gram stain used for?

A

to classify bacteria by cell wall composition

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18
Q

What will a gram-positive bacteria have?

A

-simpler walls with a large amount of peptidoglycan

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19
Q

What do gram-neg bacteria have?

A
  • less peptidoglycan

- outer membrane that can be toxic

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20
Q

What do many antibiotics target? What do they do?

A
  • peptidoglycan

- damage bacterial cell walls

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21
Q

Which type are more likely to be antibiotic resistant?

A

gram-negative

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22
Q

What also covers many prokaryotes?

A

capsule (slime layer)

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23
Q

What is an endospore?

A
  • seed that forms inside cell (with DNA)

- inactive, can remain viable in harsh conditions for centuries

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24
Q

What do fimbriae do?

A

-allow prokaryotes to stick to their substrate or other individuals in a colony

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25
Q

What are pili?

A
  • longer than fimbriae

- allow prokaryotes to exchange DNA

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26
Q

What are taxis?

A

ability to move toward or way from a stimulus

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27
Q

What is chemotaxis?

A

-movement toward or away from chemical stimulus

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28
Q

How do motile bacteria propel themselves?

A

-flagella scattered about the surface or concentrated at one or both ends

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29
Q

What are flagella composed of?

A
  • different proteins

- likely evolved independently

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30
Q

What is phototaxis?

A

-movement toward or away from light

31
Q

What are the 3 parts of a flagella?

A
  1. motor
  2. hook
  3. filament
32
Q

What is exaptation?

A

existing structures take on new functions through descent with modification

33
Q

prokaryotic cells usually lack

A
  • complex compartmentalization

- organelles

34
Q

what do some prokaryotes have? specialized _____

A

membranes that perform metabolic functions

35
Q

the _____ genome has less DNA than the _____ genome

A

prokaryotic, eukaryotic

36
Q

what does most of the genome consist?

A

circular chromosome

37
Q

where is the chromosome located?

A

in the nucleoid region

38
Q

What are plasmids?

A

smaller rings of DNA

39
Q

What is the benefit of having differences between prokaryote and eukaryotic DNA replication, transcription, translatioN/

A

-allow people to use some antibiotics without harming themselves

40
Q

How do prokaryotes reproduce?

A

binary fission

41
Q

What are 3 key features of prokaryotic reproduction?

A
  1. they are small
  2. they reproduce by binary fission
  3. short generation times
42
Q

What is an example of an extremophile bacteria?

A

-endoliths

43
Q

What are endoliths?

A

live inside rocks + between mineral grains

44
Q

What are 3 qualities of endoliths?

A
  1. found as deep as 2 miles below surface
  2. most are chemoautogtorphs
  3. reproduce maybe once per century
45
Q

What is characteristic of prokaryotic offspring?

A

generally identic

46
Q

Mutation rates are ____ during binary fission

A

low

47
Q

What is a result of rapid reproduction?

A

mutations can accumulate rapidly in a population

48
Q

Are prokaryotes primitive?

A

highly evolved

49
Q

What is the Lenski long-term evolution experiment?

A
  • ongoing study in experimental evolution

- tracking genetic changes in 12 initially identical populations

50
Q

How can prokaryotic DNA be brought together?

A

-transformation, transduction, conjugation

51
Q

what is horiziontal gene transfer

A

-move through completely unrelated bacteria species

52
Q

what happens in transformation?

A

-prokaryotic cell take up and incorporate DNA from surrounding environment

53
Q

What is transduction?

A

movement of genes between bacteria by bacteriophages

54
Q

What are the 5 steps of a virus infecting bacteria?

A
1.
2.
3.
4.
5.
55
Q

What is conjugation?

A

process where genetic material is transferred between prokaryotic cells

56
Q

What happens when a donor cell attaches to a recipient?

A

pulls it closer, transfers DNA

57
Q

what is the F factor?

A

piece of DNA required for the production of the pili

58
Q

What are 4 steps of conjugation?

A

1.
2.
3.
4.

59
Q

What does a cell with the F factor built into its chromosomes function as?

A

donor during conjugation

60
Q

What does the recipient become?

A

recombinant bacterium (DNA from 2 different cells)

61
Q

What are R plasmids?

A

carry genes from antibiotic resistance

62
Q

How do R plasmids work with antibiotics?

A

resistant to antibiotics

63
Q

What are phototrophs?

A

obtain energy from light

64
Q

What are chemotrophs?

A

obtain energy from chemicals

65
Q

What are autotrophs?

A

require CO2 as carbon source

66
Q

What are heterotrophs?

A

require organic nutrient to make organic compounds

67
Q

What are 4 major modes of nutrition?

A
  1. photoautotorphy
  2. chemoautotrophy
  3. photoheterotrophy
  4. chemoheterotropy
68
Q

What are obligate aerobes?

A

require O2 for cellular respiration

69
Q

What are obligate anaerobes?

A
  • poisoned by O2

- use fermentation or anaerobic respiration

70
Q

What are facultative anaerobes?

A

can survive with or without O2

71
Q

What is nitrogen essential for?

A

production of amino acids, nucleic acids

72
Q

What is nitrogen fixation?

A

some prokaryotes convert N2 to NH3

73
Q

what are heterocysts?

A

nitrogen fixing cells

74
Q

what happens in cyanobacterium Anabaena?

A

-photosynthetic cells + heterocysts exchange metabolic products