MicroBio 2520 ACC Summer Semester 2026 Unit 4 Lecture Test

Beta-Lactams

A group of bacteria with a ring like structure disrupts cell wall synthesis example: Penicillin,Oxicillin

Natural Penicilin

Extracted from fungal cultures BUT vulnerable tp penciliases (super bug enzymes)

Semisynthetic penicillins

Contain chemically added side chains, are less vulnerable to deactivation (from penicillinases) more stable, more absorbable, ex: Oxacillin

Vancomycin

Disrupt NAM subunits bridges from linking to each other

Bacitracin

Blocks transport of NAG and NAM from cytoplasm

Isoniazid

Disrupt mycolic acid formation in mycobacterial species

Chloramphenicol

Inhibits peptide bond formation, binds to the 50S subunity of the 70S ribosome, synthetic

Aminoglycosides

Change the shape of the 30S subunit in the 70S ribosome

example: Streptomycin, neomycin, gentamicin

Tetracyclines

Made by Streptomyces spp, it interferes with the tRNA attachment to the ribosome, penetrate tissue, suppress normal intesntinal microbiota

Erthromycin

Preventing the movement of ribosomes

Polymyxin

Attatches to the lipopolysaccharide (G-) and disrupts cytoplasmic membrane, produced by BACILLUS POLYMYXA, used for UTI caused by pseudomonas

Polyenes (Amphotericin B)

Attaches to ergosterol in funal membranes which is problematic because humans have similar cholesterol. Bacteria lack sterols and are invulnerable.

Sulfanilamide

A competitive inhibitor for with with PABA (para-aminobenzoic acid), preventing production of folic acid which disrupts synthesis of DNA and RNA

Rifamycin

inhibits messenger RNA synthesis

Nalidixic acid

Effective against prokaryotic DNA, synthetic, INHIBITS DNA GYRASE