Trastuzumab targets cancer cell receptors to halt division

Steps:

• Growth factors bind to cell surface receptors to trigger division, leading to tumors.
• Trastuzumab attaches to a specific growth factor receptor on tumor cells.
• This binding blocks the growth signal, stopping cell division.
• Such targeted binding matches the function of monoclonal antibodies, which are engineered to recognize and neutralize specific proteins.

Why A is correct:

• Monoclonal antibodies are lab-produced proteins that mimic immune responses by binding precisely to targets like HER2 receptors, as defined in immunology and oncology.

Why the others are wrong:

• B: Antibiotics kill bacteria by disrupting cell walls or protein synthesis, unrelated to receptor binding in cancer.
• C: Option is incomplete and provides no viable description.
• D: Enzyme inhibitors block catalytic sites on enzymes to halt reactions, but trastuzumab acts on surface receptors, not intracellular enzymes.

Final answer: A