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2 Flashcards

1
Q

catalyst

A

substance that helps speed up a chemical reaction and are not used up or changed during a reaction

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2
Q

anabolism

A

refers to endergonic pathways involved in biosynthesis, converting simpler molecules into complex molecules fueled by the use of cellular energy

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3
Q

catabolism

A

refers to exergonic pathways that break down complex molecules into simpler ones

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4
Q

enzyme function

A

serve as catalysts that lower the activation energy of a reaction

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5
Q

enzyme made of

A

proteins (amino acids)

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6
Q

active site

A

where substrates bond to the enzyme

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7
Q

induced fit

A

enzyme changes its structure slightly to find the best fit between the substrate and active site

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8
Q

slight temp increase affect on enzyme

A

generally increases reaction rate/enzymes catalyzed

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9
Q

affect on enzymes of increasing temp outside normal range

A

affects chemical bonds within the active site making them less suitable to bind substrates

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10
Q

high temp affect on enzymes

A

cause enzymes to denature, losing 3D structure and function. breaks bonds that fold the protein

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11
Q

denaturation

A

implies loss of secondary, tertiary, or quaternary structure and function without loss of primary structure

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12
Q

pH affect on enzymes

A

extreme pH values can cause enzymes to denature. active site amino acids have their own acidic/basic properties and are sensitive to changes in pH

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13
Q

substrate concentration affect on enzyme activity

A

activity is increased at higher concentrations or substrate until it reaches a saturation point at which the enzyme can bind no additional substrate

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14
Q

cofactor and coenzyme function

A

enzymes do not work optimally, or at all, unless bound to coenzymes or cofactors that alter the enzyme’s active site to bind substrates

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15
Q

cofactors

A

inorganic ions that help stabilize enzymatic conformation and function

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16
Q

coenzymes

A

organic helper molecules, usually vitamins, that are required for enzymatic action and are reusable

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17
Q

apoenzyme

A

enzyme lacking necessary cofactor/enzyme that is inactive

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18
Q

holoenzyme

A

enzyme with necessary cofactor/enzyme and is active

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19
Q

competitive inhibitor

A

structurally similar enough to substrate that it can compete for the enzyme’s active site by blocking the substrate from binding

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20
Q

competitive inhibitor concentration

A

in order to be effective, inhibitor concentration needs to be approx. equal to substrate concentration

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21
Q

noncompetitive (allosteric) inhibitor

A

binds to enzyme at site other than active site and blocks substrate binding by altering enzyme’s active site

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22
Q

allosteric site

A

any site on the enzyme other than the active site

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23
Q

noncompetitive inhibitor concentration

A

one noncompetitive inhibitor is needed per enzyme. equal to the amount of enzymes

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24
Q

allosteric activators

A

bind to allosteric site, cause change to active site that increases substrate affinity

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25
Q

negative feedback inhibition

A

use of pathway product to regulate its own production, product acts as an allosteric inhibitor for the enzyme that produces it

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26
Q

exoenzyme

A

extra cellular enzymes that are produced by microbes

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27
Q

exoenzyme function

A

to acquire nutrients, break down bigger molecules for transport into the cell, or evade death in order to reproduce

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28
Q

classes of exoenzymes

A

glycohydrolases, nucleases, phospholipases, proteases, amylase, catalase, lipase, beta galactosidase

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29
Q

glycohydrolase function

A

degrade hyaluronic acid that cement cells together to promote spreading through tissues

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30
Q

nuclease function

A

degrade DNA released by dying cells that can trap the bacteria, thus promoting spread

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31
Q

phospholipase function

A

degrade phospholipid bilayer of host cells, causing lysis, and degrade membrane of phagosomes to enable escape into cytoplasm

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32
Q

protease function

A

degrade collagen in connective tissue to promote spread

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33
Q

amylase function

A

degrades carbohydrates

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34
Q

catalase function

A

protects oxygen respiring organisms from toxic hydrogen peroxide by breaking it down into water and oxygen

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35
Q

lipase function

A

degrades lipids

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36
Q

beta galactosidase function

A

breaks down lactose into its monosaccharides, glucose and galactose

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37
Q

lactose monomers

A

glucose and galactose

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38
Q

sucrose monomers

A

glucose and fructose

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39
Q

toxins

A

biological poisons that assist a pathogen’s ability to invade and cause damage to tissues

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40
Q

endotoxin example

A

lipid A part of lipopolysaccharide

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41
Q

exotoxin example

A

botulinum toxin (cause botulism)

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42
Q

endotoxin source

A

gram negative bacteria

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43
Q

endotoxin compostition

A

lipid A component of lipopolysaccharide

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44
Q

endotoxin’s effect on host

A

general systemic symptoms of inflammation and fever

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45
Q

endotoxin’s heat stability

A

heat stable

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46
Q

endotoxin’s LD50

A

high

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47
Q

exotoxin source

A

primarily gram positive, some gram negative

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48
Q

exotoxin composition

A

protein

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49
Q

exotoxin’s effect on host

A

specific damage to cells dependent upon receptor-mediated targeting of cells and specific mechanisms of action

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50
Q

exotoxin’s heat stability

A

most are heat liable, some are heat stable

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51
Q

exotoxin’s LD50

A

low

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52
Q

structural genes

A

encode for products that serve as cellular structures or enzymes

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53
Q

regulatory genes

A

encode products that regulate gene expression

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54
Q

gene regulation involves three factors:

A

complex web of interactions among signals from the cell’s environment, signaling molecules within the cell, and the cell’s DNA

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55
Q

operon

A

a genome block in prokaryotes in which structural proteins with related functions are encoded together

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56
Q

promoter

A

controls the transcription of a single operon. a sequence of DNA to which proteins bind to initiate transcription

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57
Q

regulatory region

A

includes promoter and region surrounding promoter (operator), to which transcription factors can bind

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58
Q

transcription factors function

A

influence the binding of RNA polymerase to the promoter

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59
Q

types of transcription factors (regulatory molecules)

A

repressors, activator, reducer

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60
Q

operator

A

where transcription factors bind

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61
Q

operator location

A

between RNA polymerase binding site of promoter and transcriptional start site of first structural gene

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62
Q

repressor

A

transcription factor that suppresses transcription of a gene in response to an external stimulus by binding to the operator

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63
Q

activator

A

transcription factor that increase the transcription of a gene in response to an external stimulus by facilitating RNA polymerase binding to the promoter

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64
Q

inducer

A

transcription factor that either activates or represses transcription by interacting with a repressor or activator

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65
Q

constitutively expressed operons

A

transcribed and translated continuously (unregulated) to provide the cell with constant intermediate levels of the protein products

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66
Q

gene regulation

A

process used to control the timing, location, and amount genes are expressed

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67
Q

gene expression

A

process by which genes are transcribed and translated, made by the cell into proteins. synthesis of a specific protein with a sequence of amino acids that is encoded in the gene.

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68
Q

repressible operons contain genes that

A

encode for enzymes required for a biosynthetic pathway

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69
Q

repressible operon is expressed when

A

the product of the pathway is required by the cell

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70
Q

repressible operon is repressed when

A

product of pathway is not needed by the cell

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71
Q

inducible operons contain genes that

A

encode for enzymes in a pathway involved in metabolism of a specific substrate

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72
Q

inducible operons are expressed when

A

the substrate is present in the cell

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73
Q

inducible operons are repressed when

A

substrate is not found in cell

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74
Q

repressible operons are regulated by

A

the absence or presence of the product of the pathway

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75
Q

inducible operons are regulated by

A

the absence or presence of the substrate

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76
Q

trp operon: when trp is not present in the cell…

A

repressor itself does not bind to the operator, the operon is active and tryptophan is synthesized

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77
Q

trp operon: when trp is in the cell…

A

2 trp molecules bind to the repressor which changes its shape, allowing it to bind to the trp operator, blocking RNA polymerase from transcribing the structural genes, stopping expression of the operon

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78
Q

lac operon: when lactose is absent in the cell…

A

lac repressor is bound to operator, physically preventing RNA polymerase from transcribing structural genes

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79
Q

lac operon: when lactose is present in the cell…

A

allolactose serves as inducer molecule, binding to repressor, changing its shape so that it is no longer able to bind to the operator

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80
Q

First step in expressing lac operon

A

enzyme IIA becomes phosphorylated when glucose levels drop

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81
Q

Second step in expressing lac operon

A

phosphorylated enzyme IIA activates adenylyl cyclase, an enzyme that converts some of the remaining ATP to cyclic AMP (cAMP), and cAMP levels start to rise in the cell

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82
Q

cAMP

A

a cyclic derivative of AMP and important signaling molecule involved in energy metabolism in E. coli

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83
Q

third step in expressing lac operon

A

accumulating cAMP binds to catabolite activator protein (CAP) aka cAMP receptor protein (CRP) on promoter region of lac operon which increases the binding ability of RNA polymerase to the promoter region to initiate transcription of the structural genes

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84
Q

glucose: +, CAP binds: -, lactose: -, repressor: +
transcription:

A

no

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85
Q

glucose: +, CAP binds: -, lactose: +, repressor: -
transcription:

A

some

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86
Q

glucose: -, CAP binds: +, lactose: -, repressor: +
transcription:

A

no

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87
Q

glucose: -, CAP binds: +, lactose: +, repressor: -
transcription:

A

yes

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88
Q

regulon

A

a group of operons controlled simultaneously

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89
Q

global response in prokaryotes

A

there are several higher levels of gene regulation that have the ability to control transcriptions of many related operons simultaneously

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90
Q

alarmones

A

small intracellular nucleotide derivatives that are produced during impending stress

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91
Q

alarmones function

A

change which genes are expressed and stimulate the expression of specific stress response genes

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92
Q

o factor function

A

subunit of bacterial RNA polymerase confers specificity as to which promoters should be transcribed

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93
Q

altering o factor

A

cell senses specific environmental conditions, may respond by changing which o factor it expresses, degrading old one and producing new one to transcribe the operons whose products will be useful under the new environmental condition

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94
Q

example of alternate o factor

A

bacteria in the genera Bacillus and Clostridium, a group of o factors control the expression of many genes that are need for sporulation in response to sporulation-stimulating signals

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95
Q

attenuation

A

controls completion of transcription and translation. secondary stem-loop structure formed within 5’ end of mRNA being transcribed determine if transcription to complete the synthesis of this mRNA will occur and if this mRNA will be used for translation

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96
Q

attenuation example

A

controls expression of trp operon in E.coli. when terminator stem-loop forms, transcription terminates. when antiterminator stem-loop forms, it prevents the formation of the terminator stem-loop, so RNA polymerase can transcribe the structural genes

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97
Q

riboswitch: what is it?

A

a small region of noncoding RNA found within the 5’ end of some prokaryotic RNA molecules

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98
Q

riboswitch function

A

may bind to small intracellular molecule to stabilize certain secondary structures of the mRNA molecule. This determines which stem-loop forms, thus influencing the completion of mRNA synthesis and protein synthesis

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99
Q

enhancers

A

regions of DNA where proteins can bind through DNA looping facilitated between the enhancer and promoter. eukaryotic transcription influencer

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100
Q

epigenetic regulation

A

in eukaryotes, DNA molecules or associated histones can be chemically modified in such a way to influence transcription

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101
Q

methylation of cytosine nucleotides (epigenetic regulation)

A

influences use of that DNA for transcription, with DNA methylation commonly correlating to lowered levels of gene expression

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102
Q

acetylation and deacetylation (epigenetic regulation)

A

chemically modify histones, influencing the packaging state of DNA and thus affecting the availability of loosely wound DNA for transcription

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103
Q

epigenetic change heritability

A

chemical modifications can sometimes be maintained through multiple rounds of cell division, making at least some of the epigenetic changes heritable

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104
Q

extracellular matrix (biofilm)

A

where clusters of microbes are imbedded: interspersed w/ open water channels, consists of extracellular polymeric structures secreted by the organisms, makes up 50-90% of biofilm’s mass

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105
Q

extracellular polymeric structure (EPS) composition

A

hydrated gel composed of mainly polysaccharides, contains other macromolecules like proteins, nucleic acids, and lipids

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106
Q

extracellular polymeric structure function

A

key role in maintaining integrity and function of biofilm. channels allow movement of nutrients, wastes, gases. keeps cell hydrated, prevents desiccation. shelters organisms in the biofilm from predation by other microbes or cells

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107
Q

planktonic cells

A

free-floating microbial cells that live in an aquatic environment

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108
Q

sessile

A

what planktonic cells are called when they are attached to a substrate (surface)

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109
Q

First stage in biofilm formation

A

attachment of planktonic cells to a surface coated w/ a conditioning film of organic material (happens in seconds). this is reversible

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110
Q

second stage in biofilm formation

A

first colonizers become irreversibly attached (happens in seconds)

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111
Q

third stage in biofilm formation

A

growth and cellular division occur (happens in hours, days)

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112
Q

fourth stage in biofilm formation

A

production of EPS and formation of water channels (happens in hours, days)

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113
Q

fifth stage in biofilm formation

A

attachment of secondary secondary colonizers and dispersion of microbes to new sites (days, months)

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114
Q

dispersal

A

last stage (fifth) of biofilm life cycle, cells on exterior of biofilm revert to a planktonic lifestyle, sloughing off the mature biofilm to colonize new sites

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115
Q

structures required for establishment of mature biofilm

A

appendages such as fimbriae, pili, and flagella

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116
Q

metabolic collaborations in biofilms

A

when the waste product of one organism becomes the nutrient of another

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117
Q

metabolic collaboration example

A

aerobic microbes consume oxygen, creating anaerobic regions that promote the growth of anaerobes

118
Q

quorum sensing

A

the mechanism by which cells in a biofilm coordinate their activities in response to environmental stimuli

119
Q

quorum sensing function

A

can occur between different species of microbes and enables microbes to detect their cell density through the release of small molecules called autoinducers

120
Q

quorum

A

when cell population reaches a critical threshold

121
Q

autoinducer function

A

when quorum is reached, they initiate a cascade of reactions that activate genes associated w/ cellular functions that are only beneficial when a population reaches a critical density

122
Q

gram negative signaling molecules

A

communicate using N-acylated homoserine lactones

123
Q

gram positive signaling molecules

A

communicate using small peptides

124
Q

first step in quorum sensing

A

consists of the binding of the autoinducer to its specific receptor only when a threshold concentration of signaling molecules is reached

125
Q

second step in quorum sensing

A

a cascade of signaling events lead to changes in gene expression

126
Q

third step in quorum sensing

A

activation of biological responses linked to quorum sensing, notably an increase in the production of signaling molecules themselves, hence the term autoinducer

127
Q

reasons why biofilms exhibit a higher resistance to antibiotics

A

cells deep within biofilms are metabolically inactive, EPS may slow diffusion of antibiotics, phenotypic changes like increased production of efflux pumps, biofilms provide ideal environment for exchange of extrachromosomal DNA

128
Q

saliva function

A

constantly bathes teeth and gums w/ buffers and aids in maintaining a neutral pH and washes away food particles that may get stuck in the teeth

129
Q

saliva composition

A

contains buffers that neutralize acids produced during fermentation of sugars in the mouth

130
Q

dental caries

A

cavities, are microbial lesions that cause damage to the teeth

131
Q

plaque

A

a biofilm of microbes in the mouth that are attracted to the carbohydrates in the mouth

132
Q

Streptococcus mutans

A

carcinogenic species in plaque, cause of dental caries, breaks down sucrose into its monomers

133
Q

glucose, metabolized by S. mutans, is made into

A

dextran or glucan, which are part of the extracellular matrix of a biofilm

134
Q

fructose, metabolized by S. mutans, is made into

A

fermented, producing organic acids such as lactic acid

135
Q

lactic acid effect on teeth

A

dissolve minerals of tooth, including the enamel

136
Q

tartar (dental calculus)

A

when plaque biofilm becomes thick and calcifies

137
Q

fluoride function

A

protects tooth from acidity, is bacteriostatic, slowing enamel degradation

138
Q

antiseptic mouthwash function

A

contain phenolics that are stable and persist on surfaces, denature proteins, and disrupt membranes

139
Q

periodontal disease

A

result of infections that lead to inflammation and tissue damage in structures surrounding the teeth

140
Q

gingivitis

A

inflammation of the gums that can lead to irritation and bleeding

141
Q

gingivitis cause

A

when plaque accumulates on teeth, bacteria get trapped underneath and colonize, their products cause inflammation and gum damage

142
Q

bacterial products that cause periodontal disease

A

lipopolysaccharide, proteases, lipoteichoic acids, and others

143
Q

bacteria that cause periodontal disease

A

Porphyromonas, Streptococcus, and Actinomyces

144
Q

periodontitis

A

chronic gingivitis, the gums recede and expose parts of tooth below the crown, bacteria can grow and cause cavities

145
Q

severe periodontitis

A

erosion of cementum from collagenase produced by bacteria, leads to movement of teeth or loss of teeth caused by degradation of the ligament

146
Q

cementum

A

part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament, which hold the teeth in place

147
Q

trench mouth cause

A

when certain bacteria such as Prevotella intermedia, Fusobacterium spp., and Treponema vicentii are involved and periodontal disease progresses

148
Q

trench mouth symptoms

A

severe periodontitis characterized by erosion of the gums, ulcers, substantial pain when chewing, and halitosis

149
Q

characteristics of S. mutans that cause dental caries

A

the fermentation of fructose producing lactic acid and the that it can make a biofilm with the production of surface adhesion P1, which binds to salivary agglutinin on the surface of the tooth

150
Q

DNA function

A

genetic material responsible for inheritance and directs and regulates the construction of proteins necessary for cell growth and reproduction

151
Q

genome

A

contains full complement of DNA within a cell

152
Q

transcription

A

gene composed of DNA is read to produce an RNA molecule called mRNA

153
Q

translation

A

process where mRNA provides information for the ribosome to catalyze protein synthesis

154
Q

transcription and translation are referred to as

A

gene expression

155
Q

central dogma

A

states that DNA organized into genes specifies the sequences of mRNA which, in turn, specifies the amino acid sequence of the proteins

156
Q

genotype

A

the full collection of genes a cell contains

157
Q

phenotype

A

set of cell’s observable characteristics that result from the genes the cell is expressing at a given time under a certain environmental condition

158
Q

organization of genetic material

A

vast majority of organism’s genome is organized into the cell’s chromosome(s)

159
Q

diploid

A

contains two copies of each chromosome

160
Q

chromosome

A

discrete DNA structure within cells that control cellular activity, contains several thousand genes

161
Q

haploid

A

contains one copy of each chromosome

162
Q

gene

A

segments of DNA molecules that contain the instructional code necessary for synthesizing various proteins, enzymes, or stable RNA molecules

163
Q

supercoiling

A

refers to the process by which DNA is twisted to fit inside the cell

164
Q

overwound DNA

A

more than one turn per 10 base pairs

165
Q

underwound DNA

A

less than one turn of the helix per 10 base pairs

166
Q

topoisomerases

A

enzymes that help maintain the structure of supercoiled chromosomes, preventing the overwinding of DNA during DNA replication

167
Q

histones

A

DNA binding proteins that perform various levels of DNA wrapping and attachment to scaffolding proteins

168
Q

chromatin

A

combination of DNA with attached proteins

169
Q

epigenetics

A

influence of environmental factors on DNA packing

170
Q

DNA gyrase

A

type of topoisomerase, found in bacteria and some archaea, that helps prevent the overwinding of DNA

171
Q

organization of prokaryotic chromosomes

A

organized in several supercoiled domains

172
Q

noncoding DNA

A

regions of DNA that do not encode proteins or stable RNA products

173
Q

noncoding DNA location

A

commonly found in areas prior to the start of coding sequences of genes, as well as intergenic regions

174
Q

intergenic regions

A

DNA sequences located between genes

175
Q

noncoding DNA function

A

contribute to the regulation of transcription and translation through production of small noncoding RNA molecules, DNA packaging, and chromosomal stability

176
Q

extrachromosomal DNA

A

cell’s additional molecules of DNA outside the chromosome that are apart of its genome

177
Q

eukaryotic extrachromosomal DNA

A

mitochondria and chloroplasts

178
Q

prokaryotic extrachromosomal DNA

A

plasmids

179
Q

vertical gene transfer

A

transmission of genetic information from generation to generation

180
Q

genetic diversity in meiosis

A

independent assortment and crossing over

181
Q

genetic diversity in asexual organisms

A

mutations and horizontal gene transfer

182
Q

horizontal gene transfer

A

introduction of genetic material from on organism to another organism within the same generation

183
Q

HGT mechanisms

A

transformation, transduction, conjugation

184
Q

transformation

A

competent prokaryotes take up naked DNA from its environment that comes from lysed cells and recombine it in their chromosome or it remains in cytoplasm as plasmid

185
Q

naturally competent cell

A

cell naturally actively binds to environmental DNA, transport it across their cell envelops into their cytoplasm, making it single stranded

186
Q

artificial competence

A

cell reaches competence by artificial mean, use of chemicals to weaken membrane and increases permeability to make taking up extracellular DNA easier

187
Q

transduction

A

bacteriophages move short pieces of DNA from one bacterium to another

188
Q

generalized transduction

A

any piece of chromosomal DNA may be transferred to a new host cell by accidental packing of chromosomal DNA into a phage head during phage assembly

189
Q

specialized transduction

A

results from imprecise excision of a lysogenic prophage from the bacterial chromosome such that it carries with it a piece of the bacterial chromosome from either side of the phage’s integration site to a new host cell

190
Q

bacteria that gain pathogenic gene from transduction

A

Corynebacterium diphtheriae and Clostridium botulinum

191
Q

conjugation

A

DNA is directly transferred from one prokaryote to another by mean of a conjugation pilus, which brings the organisms in contact with each other

192
Q

F plasmid

A

fertility factor. genes encoding the ability to conjugate, to form an F pilus, and those involved in rolling circle replication of the plasmid

193
Q

F pilus

A

the conjugation pilus

194
Q

F+ cells

A

donor cells, contain F plasmid and are able to form an F pilus

195
Q

F- cells

A

recipient cells, do not contain an F plasmid and cannot form an F pilus

196
Q

first step in conjugation of the F plasmid

A

pilus of donor cell attaches to the recipient cell. pilus contracts, drawing cells together to make contact with one another

197
Q

second step in conjugation of the F plasmid

A

one strand of F plasmid DNA transfers from donor cell to recipient cell

198
Q

third step in conjugation of the F plasmid

A

donor synthesizes complementary strand to restore plasmid. recipient cell synthesizes complementary strand to become F+ cell with pilus

199
Q

Hfr cell

A

when plasmid DNA integrates into bacterial chromosome through recombination

200
Q

Hfr stands for

A

high frequency of recombination

201
Q

F’ plasmid

A

F plasmid is imprecisely excised from chromosome and carries with it some chromosomal DNA adjacent to the integration site

202
Q

Hfr conjugation

A

Hfr cell may treat the entire chromosome as one large plasmid and attempt to transfer whole chromosome to recipient cell. it is unusual for whole chromosome to be transferred because it takes a long time, it is only partially transfer. the recipient cell will only become a F+ cell if the whole chromosome is transferred.

203
Q

R plasmid

A

contain genes encoding proteins that make a bacterial cell resistant to particular antibiotics. can be transferred to different species and commonly contain genes conferring resistance to multiple antibiotics

204
Q

R plasmid functions

A

contain genes encoding for antibiotic resistance and contain genes that control conjugation and transfer of the plasmid

205
Q

transposons

A

molecules of DNA that include special inverted repeat sequences at their ends and a gene encoding for the enzyme transposase

206
Q

transposition

A

process by which transposons independently excise their entire sequence, and may carry additional genes, from one location of a DNA molecule and integrate into the DNA elsewhere

207
Q

nonreplicative transposons

A

transposons that move in a “cut and paste” fashion,

208
Q

replicative transposons

A

transposons that move in a “copy and paste” fashion, retaining their location in the DNA while making a copy to be inserted elsewhere

209
Q

transposon range

A

within a DNA molecule, from one DNA molecule to another, from chromosome to plasmid, from one cell to another

210
Q

bacteriophage

A

non-living infectious agents (viruses) that infect bacteria

211
Q

bacteriophage host range determined by

A

host range is bacteria and is determined by surface receptors on the target’s exterior

212
Q

bacteriophage composition

A

use DNA or RNA as genome enclosed in a capsid made of protein

213
Q

productive phage

A

a phage that goes through a lytic cycle in which it is producing more bacteriophages

214
Q

virulent phages

A

typically lead to death of the cell through cell lysis

215
Q

latent phage

A

phage that is in a lysogenic cycle where it is not actively producing more bacteriophages

216
Q

temperature phage

A

can become part of the host chromosome and are replicated with the cell genome until such a time as they are induced to make progeny viruses

217
Q

progeny viruses

A

newly assembled virses

218
Q

lytic cycle

A

virulent phage takes over the cell, produces new phages, and destroys the cell

219
Q

first stage in lytic cycle

A

attachment: phage interacts with specific bacterial surface receptors, attaching to the cell

220
Q

Second stage in lytic cycle

A

penetration: tail sheath contract and act like a hypodermic needle to inject viral genome through cell wall and membrane, enzymes degrade periplasmic peptidoglycan layer of cell wall

221
Q

third stage in lytic cycle

A

transcription: early viral genes are transcribed, synthesizing endonucleases to degrade bacterial chromosome

222
Q

fourth stage in lytic cycle

A

Replication of viral DNA and viral proteins (biosynthesis): phage hijacks host cell to replicate, transcribe, and translate necessary components for assembly of new viruses

223
Q

fifth stage in lytic cycle

A

Assembly (maturation): new virions are created by assembling parts made in previous stage, bacterial cell wall is disrupted by phage proteins holin or lysozyme

224
Q

six stage in lytic cycle

A

release (lysis): viruses burst out of cell in a process called lysis, destroying the cell. viruses are freed into environment to infect new cells

225
Q

burst size

A

number of bacteriophages that are present in the bacterial cell when it bursts and releases the bacteriophages

226
Q

lysogenic cycle

A

temperate phage genome integrates into bacterial chromosome instead of killing the cell

227
Q

prophage

A

the integrated phage genome

228
Q

lysogen

A

a bacterial host with a prophage

229
Q

lysogeny

A

process by which a bacterium is infected with a temperate phage

230
Q

lysogenic conversion

A

when the presence of a phage alters the phenotype of the host

231
Q

first stage in lysogenic cycle

A

attachment: phage interacts with specific bacterial surface receptors, attaching to the cell

232
Q

second stage in lysogenic cycle

A

penetration: tail sheath contract and act like a hypodermic needle to inject viral genome through cell wall and membrane, enzymes degrade periplasmic peptidoglycan layer of cell wall

233
Q

third stage in lysogenic cycle

A

integration: phage genome integrates into bacterial chromosome and becomes part of the host

234
Q

fourth stage in lysogenic cycle

A

binary fission: bacterium replicates its chromosome, replicates phage’s DNA and passes it to daughter cells during reproduction

235
Q

factor that causes latent phage to enter productive cycle

A

some sort of environmental pressure influencing the phage to excise out of the host’s DNA

236
Q

induction

A

excision of viral genome from host chromosome and proceeds through a lytic cycle

237
Q

intracellular targeting toxins

A

A-B exotoxins

238
Q

A-B toxins acquired by

A

Bacteriophage: lysogenic conversion

239
Q

A-B toxins components

A

A is for active enzyme B is for binding receptor

240
Q

B component function

A

responsible for cellular specificity of the toxin and mediates the initial attachment of the toxin to specific cell surface receptors

241
Q

A component function

A

after being brought into cell by endocytosis, A component enters the cell’s cytoplasm and interferes with the specific internal cellular function that it targets

242
Q

examples of A-B toxin

A

diphtheria, cholera, botulinum, and tetanus toxins that are all acquired through lysogenic conversion by a bacteriophage

243
Q

direct cell count

A

refers to counting the cells in a liquid culture or colonies on a plate. direct way of estimating how many organisms are present in a sample

244
Q

direct microscopic cell count

A

involves transferring a known volume of culture on a calibrated slide and counting the cells under a light microscope

245
Q

Petroff-Hausser chamber

A

calibrated slide used for direct microscopic cell count

246
Q

does counting chamber work on dilute or concentrated cultures?

A

more concentrated cultures, there might not be enough cells to count in dilute cultures

247
Q

does counting chamber count distinguish between live and dead cells?

A

it does not give an accurate number of live cells in a culture unless stained with fluorescence

248
Q

electronic counting device

A

counts changes in electrical resistance in a saline solution (number of cells) does not count live cells

249
Q

viable plate count

A

a count of viable or live cells and expressed as colony-forming units per milliliter

250
Q

Colony-forming units range for plate count

A

microbiologists typically count plates with 30-300 colonies

251
Q

plaque forming units

A

if bacteriophage are counted, the bacteriophage plaques formed on the lawn of appropriate bacteria

252
Q

serial dilution

A

dilutes sample to obtain plates with 30-300 CFU and the process involves several dilutions in multiples of 10

253
Q

pour plate method

A

bacterial sample mixed w/ warm agar, sample poured onto sterile plate, sample swirled to mix and allowed to solidify, plate incubated until bacterial colonies grow

254
Q

spread plate method

A

sample (0.1mL) poured onto solid medium, sample spread evenly over surface, plate incubated until bacterial colonies grow on the surface of the medium

255
Q

membrane filtration technique

A

concentrates a dilute sample by running it through a membrane that traps the microorganisms to be transferred and grown on plate

256
Q

most probable number (MPN) method function

A

a statistical procedure for estimating the number of viable microorganisms in a sample. tests dilute samples

257
Q

MPN procedure

A

tested by inoculating 5 tubes w/ 10mL of sample, 5 tubes w/ 1mL of sample, and 5 tubes w/ 0.1mL of sample

258
Q

indirect detection of cell density function

A

most commonly used to estimate and compare cell densities in a culture

259
Q

methods of indirect cell count

A

measurement of turbidity, measure of dry weight, measure cell activity by following production of metabolic products or disappearance of reactants

260
Q

pure colony

A

results when a single bacterial cell not touching any other cells multiplies

261
Q

techniques used to separate pure culture

A

pour plate, streak plate, spread plate

262
Q

pour plate technique

A

adding loop of broth culture to a tube of melted agar and then the liquid agar is poured onto sterile dish. cells are suspended in media and spread out as agar is poured to grow individual colonies

263
Q

streak plate technique

A

involves transferring loop of broth culture to surface of a solid agar medium in dish. single loop of full agar is then diluted over surface of plate

264
Q

point mutation

A

change one base in an amino acid sequence for another. includes nonsense, silence, and substitution (missense) mutations

265
Q

nonsense mutation

A

point mutation that results in a stop codon in the wrong place

266
Q

silent mutation

A

point mutation that causes no change to the amino acid

267
Q

substitution (missense) mutation

A

point mutation that one amino acid is exchanged for another

268
Q

frameshift mutation

A

deletes or inserts a base, causing changes to multiple codons and amino acids

269
Q

homologous recombination

A

a type of genetic recombination in which nucleotide sequences are exchanged between two similar or identical molecules of DNA

270
Q

Neisseria gonorrhoeae reservoir

A

humans

271
Q

Neisseria gonorrhoeae pathogenesis

A

pili and outer membrane proteins allow bacterium to attach to a variety of cell receptors, pili help prevent phagocytosis by neutrophils and increases adherence to phagocyte

272
Q

Neisseria gonorrhoeae target

A

epithelial cell receptors: urethra, cervix, pharynx, etc.

273
Q

N. gonorrhoeae action

A

produces IgA protease which destroys IgA antibodies on mucosal cells which normally blocks cell receptor sites from the bacterium

274
Q

N. gonorrhoeae enters epithelial cell by

A

endocytosis

275
Q

N. gonorrhoeae killed by

A

macrophages but persists in neutrophils

276
Q

N. gonorrhoeae causes

A

microabscesses and epithelial cell death

277
Q

N. gonorrhoeae evades antibodies by

A

regularly shedding its pili and produces new pili w/ different protein composition so no antibody is effective

278
Q

Modes of resistance for N. gonorrhoeae

A

plasmid resident resistance (enzymatic modification of drug), chromosome resident resistance (modification of microbial target)

279
Q

Plasmid resident resistance (N. gonorrhoeae)

A

produces penicillinase, genes from R plasmid, that chemically alters penicillin, making it ineffective.

280
Q

PPNG stands for

A

penicillinase producing Neisseria gonorrhoeae

281
Q

Chromosome resident resistance (N. gonorrhoeae)

A

produce altered forms of penicillin binding protein 2 (PBP2) that have decreased affinity for penicillin which prevents penicillin from binding to peptidoglycan synthesis enzymes

282
Q

CMRNG stands for

A

chromosome mediated resistant Neisseria gonorrhoeae

283
Q

Corynebacterium diphtheriae mode of transmission

A

highly contagious: droplets inhaled or contact w/ contaminated particles

284
Q

C. diphtheriae reservoir

A

humans

285
Q

C. diphtheriae causes symptoms in

A

upper respiratory tract, infects nasal tissues, larynx, and skin (ulcers)

286
Q

C. diphtheriae gets pathogenicity from

A

corynephage, bacteriophage which causes lysogenic conversion

287
Q

C. diphtheriae pathogen

A

A-B toxin

288
Q

Symptoms if C. diphtheriae

A

sore throat, fever, pseudomembrane

289
Q

lipase positive test

A

clear zone around bacterial growth on tributyrin

290
Q

catalase positive test

A

bubbling on bacterial growth on nutrient agar when hydrogen peroxide is added

291
Q

amylase positive test

A

clear zone around bacterial growth on starch agar

292
Q

beta galactosidase positive test

A

bright yellow solution with ONPG discs

Cats (6 decks)

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