1. Cellular Damage: Toxicants can cause direct damage to cells by disrupting cellular structures like membranes, proteins, and DNA. For example, oxidative stress caused by free radicals can lead to cell death.
2. Enzyme Inhibition: Some toxicants inhibit essential enzymes, thereby blocking critical biochemical pathways. For example, cyanide inhibits cytochrome c oxidase in the electron transport chain, halting ATP production.
3. Receptor Interaction: Certain toxicants bind to specific receptors, either activating them inappropriately or blocking their normal function. For instance, endocrine disruptors can mimic or antagonize hormone activity, leading to developmental and reproductive issues.
4. Genotoxicity: Toxicants that cause mutations or chromosomal damage are termed genotoxic. These agents can lead to cancer and other genetic disorders by altering the DNA sequence.
5. Immune Response: Some toxicants elicit an immune response, leading to inflammation or allergic reactions. Chronic exposure to such substances can result in autoimmune diseases.
