What do organophosphates and carbamates inhibit?

• A. Photosynthesis enzyme
• B. Cholinesterase enzyme
• C. DNA polymerase
• D. ATP synthase

Answer: (B)

Organophosphates and carbamates inhibit cholinesterase, the enzyme that breaks down acetylcholine in nerve connections. When this enzyme is blocked, acetylcholine builds up in the synapse, causing prolonged and intensified nerve signaling. Organophosphates tend to form a bond that leads to long-lasting, often irreversible inhibition, while carbamates bind more reversibly, so the effect wears off sooner. This disruption of normal neural transmission is how these pesticides control insects, but it also explains the potential toxicity in humans.

Other options don’t fit because photosynthesis enzymes operate in plants, DNA polymerase is involved in DNA replication, and ATP synthase makes ATP but is not targeted by these inhibitors.