27 Flashcards

1
Q

Gram -

A

thin peptidoglycan layer and outer
membrane

structurally more complex

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2
Q

Gram +

A

thick peptidoglycan layer

stains violet

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3
Q

Three factors contribute genetic diversity:

A
  1. Rapid reproduction
  2. Mutation
  3. Genetic recombination
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4
Q

Extremophile

A

an organisms that grows in extreme conditions or habitats

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5
Q

what is peptidoglycan

A

most bacterial cell walls contain this.

a polymer composed of modified sugars cross linked by short polypeptides

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6
Q

is gram + or gram - more resistant to antibiotics?

A

gram negative is more resistant to antibiotics because the outer membrane impedes entry of drugs

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7
Q

capsule

A

cell wall of many prokaryotes is surrounded by a sticky polysaccharide or protein layer, which is a capsule

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8
Q

nucleoid

A

prokaryotes lack a nucleus. their chromosomes are located in the nucleoid which is a region of cytoplasm that is not enclosed by a membrane

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9
Q

bacteriophages

A

viruses that infect bacteria

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10
Q

extremophiles

A

“lovers” of extreme conditions. includes extreme halophiles and thermophiles

first prokaryotes assigned to domain archaea live in extreme environments

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11
Q

extreme halophiles

A

live in highly saline environments such as the the great salt lake

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12
Q

extreme thermophiles

A

thrive in very hot environments such as hot water in Yellowstone

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13
Q

decomposers

A

break down dead organisms

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14
Q

symbiosis

A

an ecological relationship in which two species live in close contact with each other

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15
Q

parasite

A

eats cells contents, tissues, or body fluids of its host

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16
Q

pathogen

A

parasites that cause disease are pathogens, many of which are prokaryotic

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17
Q

key features of prokaryotic reproduction

A

reproduce via binary fission, short generation times, and can divide every 1 to 3 hours

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18
Q

transformation

A

a change in genotype and phenotype due to the assimilation of external DNA by a cell

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19
Q

genetic recombination

A

the recipient cell’s chromosome becomes a combo of DNA derived from 2 cells

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20
Q

conjugation

A

DNA is transferred between 2 prokaryotic cells that are temporarily joined

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21
Q

nitrogen metabolism

A

Prokaryotes can metabolize nitrogen in a wide variety of forms (including N2)

example: cyanobacteria

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22
Q

nitrogen fixation

A

convert atmospheric nitrogen to ammonia (NH3)

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23
Q

metabolic cooperation

A

metabolic cooperation between different prokaryotic species often occurs between surface coating colonies known as biofilms

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24
Q

obligate aerobes

A

must use O2 for cellular respiration and can’t grow without it

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25
Q

obligate anaerobes

A

are poisoned by O2

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26
Q

anaerobic respiration

A

substances other than O2 such as nitrate ions and sulfate ions accept electrons at the downhill end of electron transport chain

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27
Q

facultative anaerobes

A

use O2 if it is present but can also carry out fermentation or anaerobic respiration in an anaerobic environment

28
Q

kinds of extremophiles

A

Acidophile: optimum pH at or below pH 3
Alkaliphile: optimum pH levels of 9 or above
Halophile: an organism requiring at least 2M of NaCl for growth
Barophile: organism that thrives at high pressures

29
Q

mesophiles

A

do best in moderate conditions

30
Q

many archaea are not ____

A

extremophiles

31
Q

many bacteria and eukaryotes are ____

A

extremophiles

32
Q

Describe the most common shapes of prokaryotes.

A

Coccus– spherical
Bacillus– rod-shaped
Spirilum – spiral-shaped.

33
Q

prokaryotic characteristics

A
  1. Their DNA is not enclosed within a membrane and is usually a singular circularly arranged chromosome.
  2. Their DNA is not associated with histones (special chromosomal proteins found in eukaryotes); other proteins are associated with the DNA.
  3. They lack membrane-enclosed organelles.
  4. Their cell walls almost always contain the complex polysaccharide peptidoglycan.
  5. They usually divide by binary fission. During this process, the DNA is copied, and the cell splits into two cells. Binary fission involves fewer structures and processes than eukaryotic cell division .
34
Q

How do prokaryotes reproduce?

A

Bacteria reproduce by binary fission. In this process the bacterium, which is a single cell, divides into two identical daughter cells. Binary fission begins when the DNA of the bacterium divides into two (replicates).

35
Q

List and describe the three factors that contribute to the vast genetic diversity of prokaryotes.

A
  1. Rapid reproduction
  2. mutation
  3. genetic recombination
    promote genetic diversity in prokaryotes
36
Q

photoautotroph

A

energy source = light
carbon source = CO2
types of organisms = cyanobacteria, algae

37
Q

chemoautotroph

A

energy source = inorganic chemicals (H2S, NH3, Fe2)

Carbon source = CO2

38
Q

photoheterotroph

A

energy source = light
carbon source = organic compounds
types of organisms = aquatic and salt loving prokaryotes

39
Q

chemoheterotroph

A

energy source = organic compounds
carbon source = organic compounds
types of organisms = protists, fungi, animals, some plants

40
Q

What type of extremophile is a barophile?

A

is an organism which thrives at high pressures, such as deep sea bacteria or archaea

41
Q

Acidophile

A

thrive under highly acidic conditions. These organisms can be found in different branches of the tree of life, including Archaea, Bacteria, and Eukarya

42
Q

Alkaliphile

A

extremophilic microbes capable of survival in alkaline (pH roughly 8.5–11) environments, growing optimally around a pH of 10

43
Q

Psychrophile

A

extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from −20 °C to +10 °C.

44
Q

True or False: All extremophiles are Archaea, and all Archaea are extremophiles. Explain your answer.

A

False. Not all extremophiles are archaea.

Extremophiles include members of all three domains of life, i.e., bacteria, archaea, and eukarya. Most extremophiles are microorganisms (and a high proportion of these are archaea), but this group also includes eukaryotes such as protists

45
Q

Genetic variation in bacterial populations cannot result from ____

A

meiosis.

but can result from mutation!

46
Q

Photoautotrophs use ____

A

light as an energy source and CO2 as a carbon source.

47
Q

_____ involves metabolic cooperation among prokaryotic cells?

A

biofilms

48
Q

Bacteria perform the following ecological roles. Which role typically does not involve symbiosis?

A

decomposer

49
Q

Plantlike photosynthesis that releases O2 occurs in

A

cyanobacteria

50
Q

what are the shapes of bacteria ?

A

spirillum- twists like a spiral
coccus- sphere shaped
bacillus- rod shaped

51
Q

bacteria cell walls contain ____

A

peptidoglycan

52
Q

Prokaryotes are not “primitive” but are _______

A

highly evolved!

53
Q

barophile

A

organism that thrives at high pressures

54
Q

halophile

A

an organism requiring at least 2M of NaCl for growth

55
Q

Many bacteria (and eukaryotes!) are ______

A

extremophiles

56
Q

Use universal _____ to amplify specific genes

A

primers

57
Q

phototroph

A

obtain energy from light

58
Q

chemotroph

A

obtain energy from chemicals

59
Q

autotroph

A

need only CO2 or related compounds

60
Q

heterotrophs

A

Organisms that get fixed carbon from organic compounds made by other organisms (by eating the organisms or their by-products)

require at least one organic nutrient such as glucose

61
Q

chemolithotroph

A

uses inorganic reduced compounds such as hydrogen sulfide

62
Q

chemolithoheterotrophs

A

using an inorganic chemical for their energy and electron needs, but relying on organic chemicals in the environment for their carbon needs. These organisms are also called mixotrophs, since they require both inorganic and chemical compounds for their growth and reproduction.

63
Q

what do prokaryotes do for the ecosystem?

A

chemical recycling, decomposers

help the nitrogen cycle and decomposition

64
Q

whats an example of bacterial mutualism?

A

bioluminescence

65
Q

how do prokaryotes interact with humans?

A

used for PCR- polymerase chain reaction

bioremediation- use of organisms to remove pollutants from air, water and soil