Practice Questions

Cyanide is a potent enzyme inhibitor that blocks critical enzymes involved in cellular respiration, leading to severe impairment of ATP production. The other options are incorrect. Concept tested: Medical and biochemical significance of enzyme inhibition.**

Controlled inhibition ensures that metabolic pathways operate according to cellular requirements, preventing wasteful or harmful overactivity. Concept tested: Homeostatic regulation.

Non-competitive inhibitors bind at sites other than the active site and can bind regardless of substrate occupancy. Competitive inhibitors require access to the active site. Concept tested: Binding characteristics of inhibitors.

Reversible inhibitors bind through weak interactions and can dissociate from the enzyme, restoring activity. Permanent destruction occurs only with irreversible inhibitors. Concept tested: Reversible inhibition.

Since excess substrate cannot overcome non-competitive inhibition, enzyme activity remains reduced. Competitive inhibition would be reversed by increasing substrate concentration. Concept tested: Differentiating inhibitor types.

Drugs are designed to inhibit specific target enzymes while minimizing effects on normal cellular metabolism. Concept tested: Therapeutic significance of enzyme inhibitors.

Mercury forms stable bonds with sulfhydryl (-SH) groups in enzymes, causing irreversible inhibition and loss of enzyme activity. Concept tested: Heavy metal inhibition.

Toxic substances such as certain heavy metals irreversibly inhibit enzymes, causing long-lasting or permanent loss of function. Concept tested: Toxicological effects of enzyme inhibitors.

Binding at an allosteric site changes the enzyme's conformation, altering the active site's ability to bind substrate effectively. The other options are incorrect. Concept tested: Allosteric inhibition.

Competitive inhibitors compete directly with the substrate for the active site, reducing substrate binding. They do not affect enzyme synthesis or ATP production. Concept tested: Mechanism of competitive inhibition.