Question

All of the following are true statements concerning plasmids EXCEPT:

A)They can carry genes that confer resistance against antibiotics

B)They can be found in bacteria, fungi, and protozoa

C)They carry genes that are required for growth and repair

D)They are small circular molecules of DNA.

E)They can replicate autonomously

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The type of antimicrobial drug that would be most likely to have toxic effects in humans based on the premise of selective toxicity when treating microbial infection would be a drug that

A)inhibits the synthesis of the cell wall

B)inhibits metabolic pathways

C)disrupts the cytoplasmic membrane

D)inhibits protein synthesis

E)All of the above have equal potential to be toxic

Answer 1

option c

the plasmid is extracellular circular DNA present in a cell that carries origin of replication, antibiotic resistance genes, replicate independently in the cell but lack genes for growth and repair mechanism.

option E

the antimicrobial drug has selective toxicity i.e. inhibits or kills the microbial infection by causes no or minimal harm to host cell. The selective targets of the antimicrobial drug include

inhibiting the cell wall biosynthesis by blocking the peptidoglycan biosynthesis

inhibits protein synthesis by binding to different subunits of ribosomes

inhibits membrane functioning by interacting the outer and inner membranes of the lipid bilayer

also acts as competitive inhibitors (structural analogous) of several metabolic enzymes thereby causes alterations in metabolic pathways in microbials.