Micro lab Quiz #3 P2

Ch.20

selective toxicity

selectively find and destroy pathogens W/O damaging host

chemotherapy

use of chemicals to treat disease

antibiotic

substance made by microbe to inhibit other microbe in small amount

antimicrobial drugs

synthetic substance that interfere microbial growth

narrow spectrum of microbial activity

drug that affect narrow range of microbial types

broad-spectrum

affect broad range of G+ or G- bacteria

superinfection

overgrowth of normal microbiota that are resistant to antibiotics

bactericidal

kill microbe

bacteriostatic

prevent bacterial growth (static = stop)

antimicrobial drug functions:

• inhibit cell wall synthesis (ex. penicillin)

• inhibit nucleic acid synthesis

• inhibit essential metabolites (ex. sulfonamide)

• injure plasma membrane (ex. antifungul drug + sterol, polypeptide antibiotic)

what does penicillin do?

destroys peptide crossbridge in G+ (w/ B-lactam ring)

how do antibiotics (like penicilllin) stop protein synthesis?

target bacterial 70S ribosome

what do polypeptide antibiotics do? (hint: plasma membrane)

change membrane permeability

what do antifungal drugs do? (hint: plasma membrane)

combine with membrane sterols to injure plasma membrane

how to inhibit nucleic acid synthesis?

inhibit DNA gyrase that allows DNA replication/txn

how to inhibit essential metabolite synthesis?

antimetabolite (ex. sulfonamide) compete w/ normal substrate for an enzyme

What does sulfonamide compete with?

para-aminobenzoic acid (PABA) precursor to stop folic acid synthesis

what do sulfonamides do?

stop folic acid synthesis needed to make nucleic acid and proteins

antifungal drug

antiviral drug

interferon

diffusion method

minimal inhibitory concentration (MIC)

lowest antibioitc concentration preventing growth