BI323 Final Exam Material from Exam 2

Question 1

Which process are these a part of? elongation, replication, distribution, septum

Answer 1

binary fission

Question 2

division of cytoplasm to form basal cell and larger apical cell

Answer 2

baeocyte formation

Question 3

other strategies of reproduction in prokaryotes

Answer 3

spore formulation, budding

Question 4

which parts are found in the chromosome replication of E. coli?

Answer 4

origin of replication and terminus found on the chromosome, and a replisome

Question 5

what is partitioning

Answer 5

not well understood, role of MreB in cell shape and association of chromosomes

Question 6

single copy plasmid R1 replicates, ParM is anchored to ParC and ParR which attach to the origin of each plasmid, ParM elongates pushing the plasmid to opposite poles of the dividing cell, newly replicated cells with plasmid, Par proteins not synthesized until the cell readies for division

Answer 6

plasmid partioning

Question 7

involves septation, wall formation between daughter cells
steps: selection of site MinCDE, Z ring assembly (FtsZ), formation of divisome (Z ring linkage, assembly of machinery for cell wall synthesis, Z ring constriction)

Answer 7

cytokinesis

Question 8

what type of cell growth do cocci/rods go through?

Answer 8

peptidoglycan synthesis through autolysins

Question 9

used to maintain osmotic pressure
ex. choline, proline, glutamic acid

Answer 9

compatible solute

Question 10

measure of water availability to organisms related to the concentration of solutes

Answer 10

water activity

Question 11

organisms exhibit distinct _________ temperatures, which include?

Answer 11

cardinal growth, minimal maximal and optimal

Question 12

what is the order of -philes from low Celsius to high?

Answer 12

psychrophiles, psychrotrophs, mesophiles, thermophiles, hyperthermophiles

Question 13

their membranes contain unsaturated fatty acids

Answer 13

psychrophiles

Question 14

protein structure stabilization through increasing H bonds, more proline, chaperones, DNA stabilization through histone like proteins, lipid stabilization with more saturated branches and higher MW, ester linkages in archaeal

Answer 14

thermophiles

Question 15

what are these enzymes used for? superoxide dismutase, catalase, peroxidase

Answer 15

protective enzymes for oxygen concentration

Question 16

how are barophilic (piezophillic) organisms adapted to pressure changes?

Answer 16

shorter, increased unsaturated fatty acids

Question 17

x rays and gamma rays, disrupting chemical structures of DNA

Answer 17

ionizing radiation

Question 18

formation of thymine dimers, DNA repair mechanisms through photoreactivation (dimers split in light presence) and dark reactivation (dimers replaced)

Answer 18

UV radiation

Question 19

in high intensities, generates singlet oxygen which is a powerful oxidizing agent
carotenoids protect from photooxidation

Answer 19

visible light

Question 20

total biomass of organism determined by nutrient present at lowest concentration

Answer 20

liebig’s law of the minimum

Question 21

above or below certain environmental limits, a microorganism will not grow regardless of the nutrient supply

Answer 21

shelford’s law of tolerance

Question 22

what are some responses to oligotrophic environments

Answer 22

increased competition, mechanisms to sequester certain nutrients, morphological changes that increase surface area nutrient absorption

Question 23

quorum sensing in gm (-) bacteria, give some process examples

Answer 23

N-acyl homoserine lactone production
processes: bioluminescence, synthesis and release of virulence factors, conjugation, antibiotic production, biofilm production

Question 24

quorum sensing in gm (+) bacteria, give some process examples

Answer 24

often mediated by oligopeptides
processes: transformation competence, sporulation, production of virulence factors, development of aerial mycelia, antibiotic production

Question 25

controlled growth environment that can be used for certain bacteria

Answer 25

defined/synthetic media

Question 26

contain some ingredients of unknown composition or concentration, can be used for many bacteria components: peptones (hydrolysates from partial digestion), extracts( beef or yeast), agar (sulfated polysaccharide)

Answer 26

complex

Question 27

favors growth of some microorganisms while inhibiting others ex. macconkey agar selects gm (-)

Answer 27

selective media

Question 28

distinguish between different groups of microorganimss based on their biological characteristics ex. blood agar (homolytic vs non) ex. macconkey agar (lactose fermenters vs non)

Answer 28

differential media

Question 29

what are some common techniques for the isolation of pure cultures?

Answer 29

spread plate, streak plate, pour plate

Question 30

what are the characteristics used to identify colony morphology

Answer 30

form, elevation, margin

Question 31

growth is most rapid at _______ because why?

Answer 31

colony edge, availability of O2 and nutrients

Question 32

growth curves are observed in__________ which is incubated in a closed vessel

Answer 32

batch culture

Question 33

which stage does unbalanced growth occur? what is this?

Answer 33

exponential phase, change in nutrient levels, leads to shift up or shift down

Question 34

what are some starvation responses found in stationary phase?

Answer 34

morphological changes (decreased size, protoplast shrinkage, nucleoid condensation), production of starvation proteins, long term survival, increased virulence

Question 35

what is mean growth rate (µ)

Answer 35

the number of generations per hour

Question 36

mean generation (doubling) time

Answer 36

time required for the population to double in size

Question 37

what are two ways to perform direct cell counts?

Answer 37

counting chambers and electronic counters

Question 38

what are two ways to perform viable cell counts?

Answer 38

spread plating and membrane filtration methods

Question 39

a method of direct cell count, hemacytometer which is easy, rapid and inexpensive

Answer 39

petroff hausser chamber

Question 40

a method of direct cell count, cell suspension forced through small orifice that disrupts the current but can't distinguish between living and dead

Answer 40

coulter counter

Question 41

a method of direct cell count that uses a laser to scatter light and quantify

Answer 41

flow cytometry

Question 42

a method of viable cell counts that determines the population size as CFU

Answer 42

spread plating

Question 43

a method of viable cell counts that stains for easier visualization using fluorescent dyes to tell between living and dead cells

Answer 43

membrane filter

Question 44

what are three ways of measuring cell mass

Answer 44

determination of dry weight (time consuming), quantity of particular cell constituent, turbidometric measurement (light scattering)

Question 45

rate of incoming culture = rate if medium + cell removal, used when the quantity of an essential nutrient is limited, determined by rate of flow or dilution rate

Answer 45

chemostat

Question 46

a chemostat best operates at _____ dilution levels

Answer 46

low

Question 47

elimination of all microorganisms including spores

Answer 47

sterilization

Question 48

the killing, inhibition or removal of pathogens but not necessarily sterilizing

Answer 48

disinfection

Question 49

reduction to safe levels per public health standards

Answer 49

sanitation

Question 50

prevention of infection of living tissue

Answer 50

antisepsis

Question 51

dead organisms....

Answer 51

unable to reproduce under normal conditions and are VBNC (viable but not culturable)

Question 52

what are the pore measurements of membrane filters?

Answer 52

0.2 micrometers and 0.45 micrometers, N95 0.3

Question 53

autoclave degrades nucleic acids, denatures proteins and disrupts membranes

Answer 53

moist heat

Question 54

less effective because it requires high temperatures and longer exposures, oxidizes cell constituents and denatures proteins

Answer 54

dry heat sterilization

Question 55

what are the approximate conditions to heat kill bacteria

Answer 55

10 min at 60-70 celsius

Question 56

what are the approximate conditions for heat killing viruses

Answer 56

30 min at 60 celsius

Question 57

old pasteurization of milk...... new.......

Answer 57

63 celsius for 30 min, flash (HTST) 72 celsius for 15 sec, UHT 140-150 celsius for 1-3 seconds

Question 58

decimal reduction time (D)

Answer 58

time to kill 90% of microorganisms and spores at a specific temperature

Question 59

z value

Answer 59

increase in temperature required to reduce D by 1/10

Question 60

surface sterilization that doesn't penetrate, kills microorganims and inactivated viruses via thymine dimers

Answer 60

UV radiation

Question 61

how is ionizing radiation used to kill

Answer 61

via gamma rays that penetrate deep, destroying cells and endospores but not always viruses (food sterilization)

Question 62

first antiseptic common in labs and hospitals, denatures proteins and disrupts cell membranes, odor and skin irritation

Answer 62

phenol

Question 63

what are alcohols used for

Answer 63

bactericidal, fungicidal but not sporicidal and inactivates some viruses, denatures proteins and dissolves membrane lipids

Question 64

oxidizes cell constituents and iodinates proteins, may kill spores, skin damage staining and allergies

Answer 64

iodine

Question 65

iodine and organic carrier, water soluble and non-staining ex. wescodyne and betadine

Answer 65

iodophor

Question 66

used to sterilize heat sensitive materials such as sutures and catheters, microbicidal and sporicidal and combine w/inactivate proteins, penetrating packing materials

Answer 66

sterilizing gases

Question 67

conditions that influence antimicrobial effectiveness

Answer 67

1. population size 2. population composition (spores and sensitivity) 3. concentration and intensity (EtOH 95% causes dehydration but then the microbes can be brought back after rehydration) 4. exposure duration 5. temperature 6. local environment

Question 68

biological control of microorganisms

Answer 68

bacterial predators (bdellovibro gm (-) enters periplasm and eats host, bacteriophage therapy, bacteriocins

Question 69

ability of drug to kill or inhibit pathogen while damaging host as little as possible

Answer 69

selective toxicity

Question 70

drug level required for clinical treatment

Answer 70

therapeutic dose

Question 71

drug level at which drug becomes too toxic for patient, creating side effects

Answer 71

toxic dose

Question 72

comparison of toxic dose to therapeutic dose

Answer 72

therapeutic index

Question 73

what are some of antibiotic's mechanisms of action

Answer 73

1. inhibitors of cell wall synthesis 2. protein synthesis inhibitors 3. metabolic antagonists 4. nucleic acid synthesis inhibitors

Question 74

-beta lactam ring essential for bioactivity, many resistant organisms produce beta lactamase (penicillinase) which hydrolyzes a bond in the ring - blocks enzyme that catalyzes transpeptidation - only acts on growing bacteria synthesizing new peptidoglycan

Answer 74

penicillins

Question 75

factors influencing drug effectiveness

Answer 75

1. ability to reach site (venal, parenteral, topical, oral) 2. susceptibility of pathogen to drug 3. ability to reach and exceed MIC (amount, route, speed of uptake, rate of clearance) 4. acquired resistance

Question 76

what are some mechanisms of acquired resistance

Answer 76

HGT, drug inactivation, target modification, reduce concentration of the drug, use if alternative metabolic pathway

Question 77

optimal pH of 0-5.5

Answer 77

acidophiles

Question 78

optimal pH of 5.5-8.0

Answer 78

neutrophiles

Question 79

optimal pH of 8.0-11.5

Answer 79

alkalophiles

Question 79

grow at 0-35C

Answer 79

psychrotrophs

Question 79

grow at 0-20C

Answer 79

psychrophiles

Question 79

grow at 20-45C

Answer 79

mesophiles

Question 80

grow at 85-100C

Answer 80

hyperthermophiles

Question 80

grow at 45-85C

Answer 80

thermophiles

Question 81

requires oxygen and have + enzyme content for SOD and catalase

Answer 81

obligate aerobe

Question 82

prefers oxygen and have + enzyme content for SOD and catalase

Answer 82

facultative anaerobe

Question 83

ignores oxygen and had + enzyme content for SOD but not catalase

Answer 83

aerotolerant anaerobe

Question 84

oxygen is toxic and does not have enzyme content for SOD and catalase

Answer 84

strict anaerobe

Question 85

oxygen is required in 2-10% and had + enzyme content for SOD and catalase at low levels

Answer 85

microaerophile