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Microbiology Exam I > Bacterial Nutrition > Flashcards

Bacterial Nutrition Flashcards

1
Q

The metabolic capacity of bacteria is enormous because

A

have large SA to volume ratios, close contact with environment, accumulate nutrients quickly, grow rapidly

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2
Q

bacteria can be fulminant, meaning

A

infection begins suddenly, worsens quickly

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3
Q

Autotrophic metabolism

A

fix CO2, CO2 is used as building blocks

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4
Q

Chemoautotroph

A

fixing CO2 from the oxidation/reduction of inorganic ions

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5
Q

Photoautotroph

A

fixing CO2 from light energy

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6
Q

Heterotrophic bacteria

A

utilize organic molecules as building blocks via the oxidation of organic compounds

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7
Q

All bacteria that cause disease in humans are

A

heterotrophs

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8
Q

heterotrophs utilize organic molecules in what order

A

carbohydrates, proteins, lipids

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9
Q

fastidious

A

complex growth requirements, will not grow on blood agar

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10
Q

Non-fastidious

A

will grow on blood agar

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11
Q

optimal growth occurs closer to the __________ temperature

A

maximum

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12
Q

the minimal temperature growth range for bacteria is defined by

A

reduced enzyme activity and reduced membrane fluidity

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13
Q

the maximal temperature growth range for bacteria is defined by

A

protein denaturation

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14
Q

Mesophile

A

growth occurs between 20 - 55C

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15
Q

Thermophile

A

growth occurs at >55C

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16
Q

Psychrophile

A

growth occurs at <20C; a few human pathogens are facultative psychrophiles

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17
Q

Most pathogens are ________ and growth best at __________ temperature

A

mesophiles; 35-36C

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18
Q

Is refrigeration a good means to obtaining sterile conditions? why?

A

No, some human pathogens are facultative psychrophiles and grow at <20C

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19
Q

Obligate aerobic organisms

A

ONLY grow in the presence of O2

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20
Q

Examples of Obligate aerobic organisms

A

Mycobacterium tuberculosis

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21
Q

Microaeropilic organisms

A

grow in the presence of reduced concentrations of O2

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22
Q

Examples of Microaeropilic organisms

A

Campylobacter

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23
Q

Facultative anaerobic organisms

A

use aerobic respiration when O2 is plentiful (initial infection), switch to fermentation when O2 is unavailable (number of bacteria increase at infection site)

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24
Q

aerotolerant anaerobic organisms

A

can grow in the presence of O2, but grow best without

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25
Q

Obligate anaerobic organisms

A

only grow in the absence of O2 and utilizes fermentation

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26
Q

Examples of aerotolerant anaerobic organisms

A

Lactobacillus

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27
Q

Examples of Obligate anaerobic organisms

A

Clostridium and Bacteroides

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28
Q

Most human pathogens are

A

facultative anaerobic organisms

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29
Q

Most human pathogens are

A

heterotrophic, mesophilic, facultative anaerobes

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30
Q

Th effect of O2 on anaerobes

A

generation of toxic superoxides and hydrogen peroxides (O2-, H2O2), inhibiting growth or causing death

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31
Q

Oxygen tolerant (aerobes) bacteria

A

produce enzymes that detoxify superoxides and hydrogen peroxides (superoxide dismutase (SOD), catalase)

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32
Q

Superoxide dismutase

A

catalyzes the reaction of a superoxide anion + H2 = H2O2 + O2

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33
Q

Catalase

A

catalyzes the reaction of H2O2 to 2 H2O + O2

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34
Q

Oxygen intolerant (anaerobes) bacteria

A

toxic by products are produced from growth in O2, but they lack the enzymes to detoxify them

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35
Q

What antibiotics are used to treat anaerobic infections?

A

metronidazole, tindazole

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36
Q

Inorganic requirements of certain bacteria

A

inorganic requirements too high or too low can trigger changes in bacterial phenotypes

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37
Q

Low [Fe] induces

A

C. diptheriae to produce diphtheria toxin

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38
Q

Low [Ca] induces

A

plague bacterium to produce exotoxins

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39
Q

Low [Mg] induces

A

S. aureus to produce toxic shock syndrome toxin TSST-1

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40
Q

Heterotrophic metabolism is a __________ pathway

A

catabolic (oxidation of glucose into simpler carbon compounds)

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41
Q

Glycolysis

A

partially oxidize organic matter to enter other pathways and generate ATP

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42
Q

TCA cycle

A

reducing power to oxidize Carbon into CO2 to generate ATP and intermediates for anabolic pathway

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43
Q

fermentation pathway

A

substrate level phosphorylation to generate ATP, reduces compounds

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44
Q

Respiration

A

proton motive force that occurs in a membrane vesicle for ATP synthesis during the oxidation of NADH

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45
Q

Electron Transport Chain

A

transfer of electrons and hydrogen from NADH2 to terminal electron acceptors (O2)

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46
Q

Oxidase test

A

determines the presence of an ETC component (cytochrome C) by oxidation of phenylenediamine to a colored product

47
Q

Oxidase negative bacteria

A

Enterobacteria, E. coli, shigella, klebsiella, proteus, yersinia

48
Q

Oxidase positive bacteria

A

pseudomonas, pasteurella, neisseria

49
Q

ATP Synthase

A

use of the PMF to synthesize ATP

50
Q

Antibiotics that can collapse the ETC gradient

A

polymyxin, bacitracin, daptomycin

51
Q

Aerobic respiration

A

Oxidative phosphorylation, O2 serves as TEA which is reduced by H2O

52
Q

Anaerobic respiration

A

inorganic compound serves as TEA (nitrate, sulfate)

53
Q

Methemoglobinemia (MetHb) occurs when

A

elevated levels of NO3 occur in drinking water

54
Q

GI tract normal flora convert NO3 (TEA) to

A

NO2, in the blood stream could cause MetHb

55
Q

Who is at greatest risk for MetHb?

A

unborn child

56
Q

Fermentation characteristics

A

simple, less efficient, incomplete oxidation of carbon substrate, occurs in the cytosol without direct PMF

57
Q

Fermentation mechanism

A

partially oxidizes carbon compounds which serve as electron acceptors, compounds than released from the cell

58
Q

End product of fermentation in Strep. mutans of dental caries

A

lactic acid (homolactic fermentation)

59
Q

Acidic pH of the vagina and skin Lactobacillus and Propionibacterium acnes fermentation end products

A

Lactobacillus: lactic acid (homolactic fermentation)

Propionibacterium acnes: propionic acid, acetic acid, CO2

60
Q

Abscess are ______ and ________ due to fermentative metabolism of bacteria within

A

acidic and anaerobic

61
Q

Why is is difficult to treat abscess with antibiotics?

A

low pH decreases effectiveness of antibiotics, bind free nucleic acids rendering them useless, low pH kills surrounding cells and release compounds for growth

62
Q

Bacteria that only grow fermentatively

A

may lack ETC/cytochrome, use ferredoxin instead of NAD as electron carrier

63
Q

Streptococcus and Lactobacillus are

A

aerotolerant anaerobes

64
Q

aerotolerant anaerobes, Streptococcus and Lactobacillus

A

produce lactic acid and H2O2 from recycling ferredoxin, detoxification occurs by HOST catalase

65
Q

Fermentation by Clostridium results in

A

H2, CO2, and 4 carbon compounds

66
Q

hydrogen lyase

A

responsible for the recycling of ferredoxin

67
Q

Clostridium perfringens is an obligate anaerobe, infections can cause

A

large amounts of H2 to be generated which can cause gas gangrene (myonecrosis)

68
Q

Gas Gangrene due to H2

A

H2 is insoluble and works its way between tissues, opening up new locations for bacteria to colonize. H2 collapses blood vessels leading to anaerobic condition

69
Q

Proteus spp. in UTI end products

A

not related to heterotrophic metabolism, rather due to urease which converts urea to ammonia and CO2

70
Q

Proteus spp. releases urease

A

urease converts urea to ammonia causing urine pH to rise and Ca++ and ammonium form precipitate (renal calculi)

71
Q

Helicobacter pylori in stomach mucosa end products

A

release urease which cleaves urea to CO2, raising pH so H. pylori can grow, causes duodenal ulcers

72
Q

DNA primase

A

synthesizes a short ssRNA primer for DNA synthesis

73
Q

DNA gyrase (topoisomerase II)

A

negative supercoils to relieve torsional stress

74
Q

Topoisomerase IV

A

decatenation (separation of 2 daughter chromosomes)

75
Q

Topoisomerases II and IV are REQUIRED FOR

A

DNA synthesis in bacteria

76
Q

DNA synthesis is just like eukaryotes but the partitioning occurs

A

by membrane attachment in procaryotes, not spindle fibers

77
Q

RNA synthesis is just like eukaryotes, except mRNA in prokaryotes

A

is short-lived; explains why antimicrobial protein synthesis inhibitors are so effective against bacteria

78
Q

Protein translation is just like eukaryotes, except protein in procaryotes

A

is short-lived; explains why antibiotics against protein synthesis are so effective

79
Q

Sulfa drugs Sulfonilamides (sulfamethoxazole, trimethoprim) action

A

directly inhibits nucleotide synthesis to inhibit DNA synthesis/replication, protein synthesis and cell replication

80
Q

Sulfa drugs Sulfonilamides (sulfamethoxazole, trimethoprim) uses

A

uncomplicated UTI or against pneumocystis carinii in AIDS pt

81
Q

Fluoroquinolones/Quinolones (norfloxacin, ciprofloxacin) action

A

direct inhibition of DNA synthesis/DNA replication to inhibit cell replication

82
Q

Fluoroquinolones/Quinolones (norfloxacin, ciprofloxacin) uses

A

UTI and lower respiratory infections

83
Q

Rifampin action

A

direct inhibition of mRNA synthesis

84
Q

Rifampin uses

A

treat Hib, meningococcus, and Mycobacterium tuberculosis

85
Q

Chloramphenicol

A

directly inhibits protein synthesis - used against Hib meningitis, typhoid fever

86
Q

Streptogramins

A

directly inhibits protein synthesis - vancomycin-resistant enterococci, methicillin-resistant staph, drug-resistant strep

87
Q

Aminoglycosides (streptomycin, tobramycin, gentamicin, amikacin)

A

directly inhibits protein synthesis - NOT used for INTRAcellular bacteria

88
Q

Tetracyclines

A

directly inhibits protein synthesis - used against INTRAcellular bacteria

89
Q

Oxazolidinones (linezolid)

A

directly inhibits protein synthesis - used against VRE, MRSA, DRSP

90
Q

Glycycyclines (tigecycline)

A

directly inhibits protein synthesis

91
Q

Macrolides (erythromycin, azithromycin)

A

directly inhibits protein synthesis - used against INTRAcellular bacteria

92
Q

Mupiricin

A

directly inhibits protein synthesis - used topically for prevention of nasal carriage by S. aureus

93
Q

Penicillins, cephalosporin, carbapenems, monobactams

A

inhibition of cell wall synthesis

94
Q

Bacitracin

A

inhibition of cell wall synthesis - topical use only

95
Q

Vancomycin

A

inhibition of cell wall synthesis - used against MRSA and antibiotic-associated pseudomembranous colitis from clostridium

96
Q

Cycloserine

A

inhibition of cell wall synthesis - used against Mycobacterium tuberculosis

97
Q

Isoniazid

A

inhibition of cell wall synthesis - used against Mycobacterium tuberculosis

98
Q

Isoniazid

A

direct inhibition of fatty acid synthesis

99
Q

Synthesis of peptidoglycan subunits/amino sugars:

A

UDP: cytoplasmic covalent tag for directed synthesis of NAM and NAG, peptide side chain of NAM is synthesize by enzymes

100
Q

Bactoprenol

A

binds NAM–NAG complex and translocates it across the CM

101
Q

Peptidoglycan subunit is formed by the sequential

A

transfer of NAM/NAG from UDP to bactoprenol

102
Q

Transglycolase enzyme

A

transglycosylation: addition of subunit of NAM/NAG to growing end of peptidoglycan chain

103
Q

Transpeptidases

A

performs the final cross linking of the peptide stems (an amino acid from each peptide side chain)

104
Q

Bacterial Growth is dependent on

A

nutrient conditions, cultivation conditions, genotype for catabolic or anabolic pathways

105
Q

4 major phases of a bacteria growth curve

A

lag phase, log/exponential phase, stationary phase, death/decline

106
Q

Lag Phase

A

initial phase: cell volume and mass increases, DNA replication occurs, but no cell division

107
Q

Log/Exponential Phase

A

cell number, mass, volume, and cell component amounts increase exponentially

108
Q

Stationary Phase

A

no net increase in cell number

109
Q

Death Phase

A

death occurs at a logarithmic rate, mostly by autolysing

110
Q

Short mean generation time:

A

Rapidly growing organisms that produce acute disease with rapid onset and rapid progression (high antigenic dose)

111
Q

long mean generation time:

A

Slowly growing organisms that produce chronic disease with slow onset and progression (low antigenic dose)

112
Q

which antimicrobials are best for short mean generation time microbes

A

inhibitors of protein and/or peptidoglycan synthesis

113
Q

Gram stain, metabolism, external structures, or spore producing ____________ effect generation time

Microbiology Exam I (13 decks)

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