Microbial Biology Exam 3

decimal reduction value

time required to kill 90% of the microbial population under specific conditions

d-process

conditions (dose, time, etc) that reduces the number of microbes by one exponent

MIC

minimum inhibitory concentration

MBC

minimum bactericidal concentration

-cides

agents which kill microbes

germicides

kill microorganisms and viruses but not necessarily endospores

-static

agents which prevent microbial growth, if removed organisms are able to start growing again

incineration

method of dry heat sterilization, oxidizes cell to ashes, used to destroy medical waste and animal carcasses

chemotherapy

the use of drugs to treat a disease

antimicrobial drugs

interfere with the growth of microbes within a host

selective toxicity

a drug that kills harmful microbes without damaging the host

penicillins (-cillins)

most effective against gram positives, extended spectrum

cephalosporins (cefe, cepha-)

sulfur containing ring

monobactam (-onam)

single ring

carbapenems (-penem)

substitute a C for an S, add a double bond

vancomycin

targets NAG-NAM linkages in peptidoglycan, drug of last resort for MRSA

polymyxins

bind LPS in gram negative outer membrane, drug of last resort for MDR gram negative infections

chloramphenicol

binds 50S subunit, inhibits peptide bond formation, derived from streptomyces

tetracyclines

interferes with tRNA attachment, derived from streptomyces

aminoglycosides

inhibit 30S ribosome, misalignment of mRNA, derived from streptomyces

macrolides

mycins from streptomyces, binds 50s, prevents translocation, blocks peptide tunnel

linezolids

bind large ribosomal subunit, block peptide bond formation

rifampin

RNA polymerase (blocks tunnel), key TB treatment

fluoroquinolones

target bacterial gyrase, induces breaks in DNA, can treat intracellular infections

metronidiazole

activated by anaerobic bacterial/amoebal ferredoxin/flavodoxin, causes breaks in dsDNA

sulfonamides (sulfa drugs)

inhibit folic acid synthesis

replicon

portion of the genome that contains an origin and is replicated as a unit

slow growth rate

DNA replicated then septation begins

rapid growth rate

DNA replicated and new round of DNA replication begins before separation begins

PCR

copies DNA, read result with gel

RT-PCR

copies RNA

Q-PCR

copies RNA or DNA, quantifies the amount of product

reverse transcriptase

copies RNA to DNA, enzyme is found in retroviruses

transcription

the synthesis of a strand of RNA from a DNA template

operon

a collection of genes all under the control of a single promoter

repressible

protein + small molecule = no transcription

inducible

protein + small molecule = start transcription

negative control

protein + DNA = no transcription

positive control

protein + DNA = start transcription

peptide bond formation

catalyzed by rRNA

vertical gene transfer

occurs during reproduction between generations of cells

horizontal gene transfer

the transfer of genes between cells of the same generation

competence

bacterial cells are capable of taking up and integrating larger fragments of DNA

virion

complete virus particle

scaffolding proteins

viral encoded proteins that aid in construction of procapsid

endolysin (T4)

attacks peptidoglycan

holin (T4)

produces lesion in cell membrane

prophage

integrated phage genome

lysogeny

integration of viral genome into host DNA

lysogens

infected bacterial host