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BI276: Microbes > Final Exam > Flashcards

Final Exam Flashcards

1
Q

a genome contains?

A

genetic information in a cell

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2
Q

a genotype is?

A

the genetic makeup containing potential properties

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3
Q

what is DNA gyrase?

A

bacteria have a singular circular chromosome, supercoiled and attached to the plasma membrane

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4
Q

ecoli DNA has____ base pairs?

A

46 million

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5
Q

what is genomics?

A

sequencing and molecular characterization of genomes

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6
Q

how is supercoiled DNA made?

A

relaxed circle of dna folded over each other, result in the contact between the helix in two places, dna gyrase action, twisting introduces

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7
Q

what are the 3 stages of molecular information flow?

A

replication(duplication of dna), transcription (dna participation in protein synthesis through rna) and translation (determination of amino acid sequence)

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8
Q

Dna gyrase activity is inhibited by?

A

quinolones, fluoroquinolones, novobiocin

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9
Q

Archaea uses _______ gyrase?

A

reverse

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10
Q

does cellular dna replicate before or after division?

A

before cell division

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11
Q

what is semiconservative replication?

A

each new double stranded dna molecule contains one original strand and one new strand

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12
Q

DNA is replicated from the ____ end?

A

3’

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13
Q

Dna in some bacteria is________?

A

biderctional

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14
Q

what are the steps to transcription?

A
  1. enzymes unwind from double helix
  2. proteins stabilize the unwound parental dna
  3. leading stand synthesized continuously by dna polymerase
  4. lagging strand synthesized discontinuously
  5. dna polymerase digests rna primer and replaces it with dna
  6. dna ligase joins the discontinuous fragments of the lagging strand
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15
Q

rapid amplification of Dna in vitro is?

A

polymerase chain reaction

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16
Q

PCR uses DNA _____?

A

polymerase

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17
Q

what are used to run through repeated cycles of heating and cooling in the PCR?

A

thermocyclers

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18
Q

transcription synthesizes _____ from _____?

A

dna from rna

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19
Q

what are the 3 types of rna used in transcription?

A

mrna, rrna, trna

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20
Q

what is used in the rna nucleotide instead of thymine?

A

uracil

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21
Q

what enzyme does transcription use?

A

rna polymerase

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22
Q

translation includes sense condons that?

A

code for amino acids

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23
Q

in bacteria what does the start codon AUG code for?

A

formulmethione

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24
Q

what are nonsense codons?

A

stop codons that signal the end of protein molecule

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25
Q

during translation what asists the transport of required amino acids during protein synthesis?

A

trna

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26
Q

why can translation of mrna into proteins begin before transcription is complete in prokaryotes?

A

since mrna is produced in the cytoplasm

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27
Q

what is repression?

A

regulatory mechanism that inhibits gene expression and decreases synthesis

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28
Q

what is repression response of?

A

overabundance of end product mediated by repression proteins

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29
Q

what is induction?

A

process that turns on transcription of a gene induced by an inducer (ex. lactose metabolism in ecoli)

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30
Q

what is used for the regulation of bacterial gene expression?

A

operon model of expression

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31
Q

francis jacob and jaques monod are responsible for ?

A

model for regulation of protein synthesis

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32
Q

what is the main idea of the operon model of suppression?

A

structured genes are regulated together

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33
Q

what is an operon?

A

set of operator and promoter sites and structural genes

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34
Q

what is a mutation?

A

change in the base sequence of dna

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35
Q

a silent mutation is?

A

may not be affected by actual function of encoded protein

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36
Q

a mutation where a single base is replaced is?

A

point mutation

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37
Q

a missenese mutation is?

A

base substitution results in amino acid substitution

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38
Q

a mutation where a stop codon is created is?

A

nonsense

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39
Q

a mutation where there is deletion insertion to cause a shift is?

A

frameshift

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40
Q

a spontaneous mutation is?

A

occurs in the apparent absence of mutation

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41
Q

mutagens are?

A

environmental agents that directs or indirectly bring out mutations

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42
Q

chemical mutatgens consist of ?

A

nitrous acid

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43
Q

what creats thymine dimmers during radiation?

A

uv light

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44
Q

what are light repair enzymes?

A

photolysases use visible light energy to separate dimer

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45
Q

what is dark repair?

A

nucleotide excision repair

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46
Q

what is the muattion rate?

A

probability that a gene will mutate when a cell divides

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47
Q

spontaneous mutation rates are usually high or low?

A

low

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48
Q

how do mutagens affect the frequency of mutation?

A

increase the spontaneous rate of mutation usually by 10-1000 times

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49
Q

how is identifying mutations easier in prokaryotes?

A

effects of mutated gene are not masked by normal versions as in most eukaryotes

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50
Q

what is positive or direct selection?

A

detection of mutant cells by rejection of unmutated parent cells

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51
Q

what is negative or indirect selection?

A

indifies cells that cannot preform a certain function

52
Q

what is an auxotroph?

A

any mutant microorganism with a nutritional requirement that is absent in the parent

53
Q

a carcinogen is?

A

mutagens that cause cancer

54
Q

what is an ames test?

A

use bacteria as carcinogen indictaters based on back mutations or reversions

55
Q

the removal or destruction of all forms of microbial life?

A

sterilization

56
Q

commercial sterilization?

A

limited heat treatment sufficient to destroy spores of clostridium

57
Q

disinfection is?

A

control directed at destroying harmful microorganisms

58
Q

antisepsis is?

A

disinfection applied to living tissue

59
Q

mechanical removal is?

A

degerming

60
Q

sanitization is?

A

lowering microbial counts to safe public health levels

61
Q

bacteriostasis is?

A

does not kill but stops or stays further growth

62
Q

asepsis is?

A

absence of significant contamination

63
Q

biocide or germicide is?

A

cide to kill, death occurs at constant rate

64
Q

what are 3 affects of antimicrobial treatments?

A

number of microbes, environmental influences, exposure time

65
Q

alteration of membrane permeability causes?

A

leaky cells ,lots of cellular contents

66
Q

heat kills primarily through?

A

enzyme denaturation

67
Q

what is thermal death point?

A

lowest temperature at which microorgansims in a liquid will be killed in 10 minutes

68
Q

thermal death time?

A

minimum length of time for all bacteria in a liquid culture to be killed at a certain temperature

69
Q

decimal reduction time is?

A

in which 90% of a population of bacteria at a given temp

70
Q

______ kills microrganisms through coagulation of proteins ?

A

moist heat

71
Q

what lowers microbial numbers and eliminates pathogenic microorganisms?

A

pasteurization

72
Q

what is hist?

A

high temperature short time pasteurization

73
Q

what is filtration used for?

A

sterilize heat sensitive materials

74
Q

what bacteria grows slowly at refrigerator temperatures?

A

pychotrophs

75
Q

what is desiccation?

A

viability retained but reproduction and growth ceases

76
Q

osmotic pressure is used in?

A

food preservation

77
Q

what have high electron beams?

A

gamma rays, x rays

78
Q

what does the target theory of damage do?

A

creates sufficient mutations to import lethality

79
Q

what wavelength has little affect of microorgansims?

A

microwaves

80
Q

how many bacteria is the disinfectant solution tested with?

A

3 bacteria (salmonella cholerasus, staphlococcus aureus, pseudomonos aeruginosa)

81
Q

what is the disk diffusion method?

A

disks of filter paper containing agents or antibiotics are placed on an agar plate and monitored for zones of inhibition

82
Q

what are 6 types of disinfectants?

A

phenol and phendics, bisphenols, biguanides, halogens, alkohols, heavy metals.

83
Q

who established the magic bullet theory?

A

paul enrlich

84
Q

who first found penicillin?

A

alexander flemming

85
Q

how does narrow spectrum differ from broad spectrum?

A

broad (inhibit gram negative and positive)

narrow (primarily gram positive)

86
Q

inhibition of cell wall synthesis can react with which subunits?

A

30s or 50s

87
Q

disruption of the plasma membrane results in ?

A

metabolite loss

88
Q

what inhibits cell wall synthesis?

A

penicillin, carabaperems

89
Q

what do semi synthetic penicillins do?

A

remove and replace side chains from the neutral molecule

90
Q

what are carabaperems?

A

class of b-lactam antibiotics

91
Q

monobactams have ______ toxicity?

A

low

92
Q

what time of ring structure do monobactams have and what bacteria do they affect?

A

single, and affects only gram negative bacteria

93
Q

what are cephalosporins?

A

inhibit cell wall structure, resistant to penicillin, affective against gram negative

94
Q

what inhibits protein synthesis, has a broad spectrum and can be toxi to the host?

A

chlaramphenicol and aminogycosides

95
Q

what are tetracyclines?

A

broad specrum, inhibit protein synthesis, penetrate body tissues, affective against stds

96
Q

what are macroslides?

A

contain macrocyclic lactone ring, most affective against strepto cocci

97
Q

what is polymyxin B ?

A

effective against gram negative bacteria, injures plasma membrane, used against infections caused by pseudomonas

98
Q

what inhibits rna synthesis?

A

rifamycins

99
Q

what do quinolones do?

A

selectively inhibit dna gyrase required in dna replication?

100
Q

what are sulfonamidas?

A

sulfa drug, among first synthetic drugs to treat microbial disease

101
Q

what is an antifugal drug?

A

used against athletes foot, and yeast infections

102
Q

what are 4 types of drug resistance?

A

1) destruction or inactivation of the drug
2) prevention
3) altertion of target site
4) rapid efflux

103
Q

what do nitrogen fixing bacteria do?

A

fix nitrogen , obligately aerobic, members of alpha or gamma proteobacteria

104
Q

what are enteric bacteria?

A

homegenous group of gram negative non spoulating bacteria, facuulatively aerobic

105
Q

vibrio and photobacterium are?

A

mostly aquatic and fermentive metabolism

106
Q

what are rickettsias?

A

obligate intacellular parasites, significant human pathogens

107
Q

what are spirillia?

A

motile and spiral shaped, nitrogen fixers

108
Q

what are sheathed proteobacteria?

A

filamentous beta with unique life cycle, formation of flagellated swarmer cells with long tube or sheath

109
Q

organisms that form varous cytoplasmic extrusions are?

A

stalked bacteria

110
Q

what ar gliding myxobacteria?

A

specialized form of motility, members of delta proteobacteria,

111
Q

what functions as electron acceptors under anoxic conditions?

A

sulphate and sulfur

112
Q

phylum 2 consists of?

A

gram positive bacteria

113
Q

phylum 2 is divided into 2 subdivisions which are?

A

high gc and low gc

114
Q

low gc gram positive bacteria are ?

A

sporeformers

115
Q

what are two characteristics staphlococci?

A

nonspore, common parasite of humans, found on skin and mucous membranes, produce toxins

116
Q

what are lacto bacilli?

A

includes lactic acid bacteria, produces lactic acid as byproduct, grow anaerobically

117
Q

what are two properties of streptococci?

A

produce acidic byproducts, classified according to reactions on blood sugar

118
Q

what are listeria enterococcus?

A

gram positive cocco bacilli, survives refrigeration temps

119
Q

what are mycoplasms?

A

no walls, highly peomorphic, smallest self replicating organisms

120
Q

what are cryneform bacteria?

A

rod shaped, irregular cell arrangements, include animal and plant pathogens

121
Q

what are propiohic acid bacteria?

A

discovered in swiss cheese, ferment glucose to propiohic acid

122
Q

what are mycobacterium

A

distinctive cell wall (acid fast stain), seperated into slow and fast growing groups

123
Q

what are actinomycetes?

A

group of filamentous bacteria, soil organisms

124
Q

phylum 3 consists of?

A

cyanobacteria, blue green pigment, oxygenic photosynthesis, n fixing cells

125
Q

what are prochlorophytes?

A

oxygenic phototrophs containing chlorophyll

126
Q

what are the assorted phyla ?

A

chlamydia
spirochates
bacteriodetes
fusobacteria

BI276: Microbes (4 decks)

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