Microbiology midterm

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114 Terms

1
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What makes streak plates successful

Single colonies

2
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What are aseptic techniques

Sterilization, making sure things are wiped down, flaming the lips of things

3
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What are the different energy classes

Chemoorganotrophs, chemolithotrophs, phototrophs, heterotrophs, autotrophs

4
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What is exergonic

Reactions with a negative delta G that release free energy

5
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What is endergonic

Reactions with a positive delta G that release free energy

6
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What does a catalyst do

Lowers the activation energy of a reaction therefore increases the reaction rate

7
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What are typical characteristics of enzymes

Highly specific, biological catalysts, larger than substrates

8
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What kind of enzyme is the ribosome

It is an anabolic enzyme that builds the protein up

9
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What happens to the burning of ATP in the beginning steps of glycolysis

It helps energize the substrate so that it can be split

10
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How many net ATP’s are produced in glycolysis

2

11
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Does glycolysis use oxygen

Glycolysis is anaerobic

12
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What is the purpose of fermentation

Regenerate NAD+

13
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How many ATP’s are in aerobic glycolysis

38 ATP

14
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How is the electron transport chain oriented in the cytoplasmic membrane

Oriented so that the electrons are separated from the protons

15
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What does the final carrier in the ETC do

Donates the electrons and protons to the terminal electron receptor

16
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Where do the protons originate during the proton motive force

From NADH and the dissociation of water

17
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What is the pH gradient like in the PMF

The inside is negative and alkaline and the outside is positive and acidic

18
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What is the importance of the CAC

It is the pathway that pyruvate is completely oxidized to CO2

19
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From the microbes perspective, what is the main goal of the CAC

Biosynthesis, with importance on the intermediates

20
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What happens to all the carbon in glucose

It ends up as CO2 in the CAC and prep steps

21
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Why does bacteria need to produce sugars

For cell wall build up and for its DNA and RNA

22
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What are the important polysaccharides for biosynthesis

N-acetylglucosamine and N-acetylmuramic acid

23
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Why is synthesis of gluconeogenesis important

Phosphoenolpyruvate is synthesized from oxaloacetate

24
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What are pentoses required for

The synthesis of nucleic acids

25
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How are pentoses formed

By the removal of a carbon atom from hexose

26
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Where do carbon skeletons come from

The intermediate steps of glycolysis or CAC

27
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What protein is involved in fatty acids

Acyl carrier protein

28
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What happens during the final assembly of lipids in bacteria and eukarya

The fatty acid is added to a glycerol

29
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What happens to the final assembly of lipids in archaea

A phytanyl side chain is added to glycerol

30
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Can all prokaryotes fix nitrogen

No

31
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Where are nitrogen fixers found

Can be free living or symbiotically with plants

32
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The nitrogen reaction is catalyzed by what

Nitrogenase

33
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What are nitrogen fixing bacteria sensitive to

Oxygen

34
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What is teh final product of nitrogen fixation

Ammonia

35
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Why does nitrogen fixation use up so much ATP

The more waste that bacteria take up the more ATP they need to burn

36
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How is nitrogenase assayed

With a acetylene reduction assay

37
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What instrument is used for an acetylene reduction assay

Gas chromatograph

38
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What is the acetylene reduction assay used for

To see if the bacteria is nitrogen fixing

39
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What is peptidoglycan

Feature of cell wall

40
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What is bactoprenol

A carrier molecule that inserts peptidoglycan precursors

41
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What is the function of glycolases

Interact with bactoprenol and catalyze glycosidic bond formations

42
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What is transpeptidation

Final step in cell wall synthesis, inhibited by penicillin

43
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What is exponential growth

Growth of the microbial population where cells double in specific time intervals

44
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What is a batch culture

A closed system of microbial cultures in a fixed volume

45
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What are the growth phases of a batch culture

Lag and log phase

46
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What phases uses binary fission in a batch culture

Log, stationary and death

47
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What is a continuous culture

An open system of microbial culture in a fixed volume

48
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What is a common continuous culture device

Chemostat

49
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What is an important aspect of a chemostat

The growth rate and population density of the culture can be controlled independently and simultaneously

50
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What controls the growth rate in a chemostat

Dilution rate

51
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What controls the growth yield in a chemostat

Concentration of limiting nutrient

52
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What happens if the dilution is too high in a chemostat

The organism washes out

53
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What happens if the dilution rate is too low in a chemostat

The organism will die of starvation

54
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How can microbial cells be enumerated

By microscopic observations or hemacytometer

55
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Why are direct counts (microscopic counts) unreliable

Cells could be dead or alive and is hard to count if clumped

56
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What are the 3 ways to perform plate counts

Spread, pour, spiral

57
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What is true of every microbial colony

Is an outgrowth of a single colonies viable cells

58
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What needs to be done to obtain an appropriate colony count

The sample needs to be diluted

59
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What are disadvantages of spiral plating

Very expensive

60
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What are characteristics of viable counts

Not culturally, unreliable, alive but cant grow

61
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What are characteristics of turbidity measurements

Indirect, rapid, non destructive

62
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What is teh measurement of turbidity called

Optical density

63
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What measures optical density

Spectrophotometer

64
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What characteristics of bacteria would cause changes in a standard curve

Cell size, shape, clumping

65
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At high optical densities what happens to spectrophotometer readings

They are not as accurate

66
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What determines the minimum growth curve

The membrane becomes stiff and ‘gelling’

67
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What determines the maximum growth curve

Protein denaturing

68
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What is a psychrophile

Grows in low temperatures

69
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What is a mesophile

Grows in midrange temps

70
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What is a thermophile

Grows in high temps

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What is a hyperthermophile

Grows in extremely high temps

72
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What would be most associated with the human body

Mesophiles

73
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What kind of fatty acids are in psychrophiles

Unsaturated fatty acids

74
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What kind of fatty acids are in thermophiles

Saturated fatty acids

75
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What kind of bacterial diversity is found in hyperthermophiles in hot springs

High prokaryotic diversity

76
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What enzyme is produced by hyperthermophiles

Taq polymerase

77
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What motive force does some alkaliphiles have

Sodium motive force

78
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What is the internal pH of a cell

Close to neural, outside the cell can be high or low pH

79
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Bacteriostatic

Prevents microbial growth

80
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Bacteriocidal

Kills the cell

81
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Bacteriolytic

Kills and lysis the cell

82
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What does MIC stand for

Minimum inhibitory concentration

83
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Why is the MIC needed

To inhibit growth of microorganism with the smallest amount of agent

84
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What is a disc diffusion assay

Solid media with an antimicrobial gent added to filter paper disks

85
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Does a larger inhibition zone when doing a disk assay mean its a better antimicrobial

The diameters don’t related to activity it means that there is activity

86
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Where do haalophiles form best

In areas with high salt concentration and reduced water potential

87
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Where do osmophiles grow best

In high sugar environments

88
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Where do xerophiles grow best

In dry environments

89
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What ways can reduce microbial growth

Microwaves, UV, x-rays, gamma rays,

90
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What could be missing in a bacterial cell wall

A cell wall

91
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What domain makes up 60% of all biomasses on earth

Bacteria

92
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Genetic material of prokaryotic cells

Consist of chromosomes and plasmids, usually circular and double stranded, consists of multiple chromosomes, contain millions of base pairs

93
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The person who first described bacterial cells was

Anton Van Leeuwenhoek

94
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The person who debunked spontaneous generation

Louis Pasteur

95
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The father of infectious disease

Robert koch

96
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What does a pure culture refer to

Only a single type of organism in the culture

97
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Koch’s postulates are designed to

Determine the causal agent of a disease

98
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A main advantage of microbial cells being small is

Greater surface to volume ratio

99
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Most membrane associated transport proteins would be

Integral

100
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Which is not a difference between gram positive and gram negative cells

Presence or absence of fermentative abilities