week 11: controlling microbial growth

Question 1

two categories of controlling microbial growth

Answer 1

physical, chemical

Question 2

examples of physical methods

Answer 2

oven, autoclave, boiling, flash pasturization, filtration, uv light

Question 3

examples of chemical methods

Answer 3

iodine, alcohol, soap, bleach

Question 4

heat generally kills microbes by

Answer 4

denaturing proteins

Question 5

sterilization

Answer 5

complete elimination of microbes

Question 6

dry heat sterilization

Answer 6

requires high temp and longer treatment times

Question 7

moist heat sterilization tools

Answer 7

reduces temp required

Question 8

pasteurization is used to

Answer 8

preserve liquids that cannot be boiled

Question 9

batch pasteurization

Answer 9

65 degrees C for 30 mins

Question 10

flash pastuerization

Answer 10

72 degrees C for 15 seconds

Question 11

flash pasteurization kills

Answer 11

mesophiles, most likely to be pathogenic

Question 12

ultra pasteurization

Answer 12

134 degrees C for 1-2 seconds

Question 13

how does cold prevent microbial growth

Answer 13

reducing the availability of food

Question 14

what size filter is small enough to prevent bacteria

Answer 14

0.45um

Question 15

radiation causes

Answer 15

mutations in the genetic material of a microbe

Question 16

disinfectants are used to

Answer 16

reduce contamination on non living material

Question 17

antiseptics are used to reduce contamination on

Answer 17

living tissue

Question 18

chemotherapeutics are used to reduce

Answer 18

contamination within living tissue

Question 19

phenolics

Answer 19

kill microbes by denatiruing proteins - listerine and lysol

Question 20

chlorine

Answer 20

kills microbes by forming an acid when mixed with water

Question 21

alcohol

Answer 21

kills microbes by denaturing protiens and disrupting cell membranes

Question 22

detergents

Answer 22

killls microbes by creating leaky cells

Question 23

heavy metals

Answer 23

kills microbes by interfering with protein structure

Question 24

bacteria require ______ in order to convert it to folic acid which is essential for replication

Answer 24

para aminobenzoic acid

Question 25

the enzyme responsible for converting PABA to folic enzyme cannot distinguish between

Answer 25

PABA and sulfanilamide

Question 26

when sulfanilamide binds to the enzyme instead it

Answer 26

prevents folic acid production, halting replication

Question 27

why are human cells not affected by sulfa drugs

Answer 27

humans dont have the enzyme that converts PABA to folic acid

Question 28

spectal activity range, broadest to narrowest

Answer 28

tetracyclin, sulfa drugs, streptomycin, erythromycin, penicillins, isoniazid

Question 29

drugs that inhibit gram + and - cell walls

Answer 29

penicillins, cephalosporins, vancomycin

Question 30

drugs that inhibit acid fast cell walls

Answer 30

isoniazid

Question 31

how do penicillins inhibit cell wall synthesis

Answer 31

penicillins interfere with the synthesis of the pentaglycine bridges that connect peptidoglycan layers in bacterial cell walls. This compromises the integrity of the cell wall causing it to take in water from the environment until it bursts

Question 32

how does vancomycin inhibit cell wall synthesis

Answer 32

used against gram positive bacters bc cannot penetrate outer membrane of gram negative

Question 33

how does isoniazid inhibit cell wall synthesis

Answer 33

inhibits mycolic acid synthesis

Question 34

erythromycin binds to

Answer 34

bacterial ribosome preventing it from moving along the mRNA template; preventing translation

Question 35

tetracyclines block

Answer 35

binding between tRNA and the ribosome, preventing translation

Question 36

chloramphenicol blocks the formation of

Answer 36

peptide bonds between amino acids, preventing translation and protein synthesis

Question 37

streptomycin blocks effective translation by

Answer 37

altering the structure of the bacterial ribosome so that codons are misread and translation is innefective

Question 38

rifampin binds to

Answer 38

rna polymerase, blocking bacterial transcription

Question 39

ciprofloxacin inhibits bacterial replication by binding to

Answer 39

DNA polymerase and preventing dna from unwinding

Question 40

cell wall production in inhibited by

Answer 40

vancomycin, cephalosporins, isoniazide and penicillin

Question 41

ribosome is inhibited by

Answer 41

tetracyclin, erythromycin, chloramphenicol, streptomycin, gentamycin

Question 42

enzyme is competitively inhibited by

Answer 42

sulfa drugs

Question 43

dna replication is inhibited by

Answer 43

ciproflaxin

Question 44

rna polymerase is inhibited by

Answer 44

rifampin

Question 45

why is selective toxicity difficult to achieve against eukaryotic microbes

Answer 45

the structure of the cells are so similar to our own

Question 46

polyenes

Answer 46

binds more readily to ergosterol compared to cholesterol, disrupting the fungal membrane

Question 47

azoles

Answer 47

interfere with ergosterol synthesis

Question 48

protozoa

Answer 48

prevent hemoglobin digestion by the parasite while residing in red blood cells

Question 49

reverse transcriptase inhibitors

Answer 49

mimic the structure of a nucleotide, incorporate it into DNA molecules during reverse transcriptase; ultimately preventing DNA replication

Question 50

protease inhibitors

Answer 50

prevents proteases from cleaving large proteins into smaller fragments important for viral synthesis

Question 51

why is acyclovir used against herpesvirus

Answer 51

resembles sugar base subunit, acting as a false nucleoside, viral replication is selectively hindered while host DNA replication remains