How do insecticides induce oxidative stress?

• A. By generating reactive oxygen species or overwhelming antioxidant defenses, damaging proteins, lipids, and DNA.
• B. By blocking photosynthesis in plants.
• C. By increasing ATP production.
• D. By stabilizing membranes.

Answer: (A)

Insecticides can cause oxidative stress because they push the cellular balance toward reactive oxygen species (ROS) faster than the insect’s antioxidant defenses can cope. This overproduction of ROS may occur directly, or indirectly as detox systems (like glutathione, catalase, and superoxide dismutase) are overwhelmed while metabolizing the insecticide. When ROS accumulate, they attack and modify essential cellular components: lipids in membranes undergo peroxidation, proteins incur oxidative changes that disrupt function, and DNA can be damaged. This cascade disrupts cell integrity and signaling, leading to cell death and, ultimately, insect death. The other ideas don’t describe why oxidative stress happens in insect cells: blocking photosynthesis is irrelevant to insects, who don’t rely on photosynthesis; increasing ATP production doesn’t reflect ROS-driven damage; stabilizing membranes would counteract stress rather than cause it.