a. decreases permeability of the cell membrane. b. competitive inhibition of paba results in a reduction of folic acid. c. blocks formation of peptidoglycan which weakens the cell wall. d. interferes with rna synthesis; blocks transcription. e. interferes with protein synthesis; broad spectrum, bacteriostatic drug; effective against gram negative and postive bacteria, and intracellular bacteria.(some fungi also). f. interferes with protein synthesis; narrow spectrum against gram positive bacteria and eye infections in newborns. g. dna synthesis inhibitor; synthetic antimicrobial agent (broad spectrum); used to treat resistant organisms. h. interferes with mitosis by binding microtubules.