Paris green kills
**Core Concept**
Paris green is a historical arsenical compound used as a pigment and for various industrial applications. It exerts its toxic effects through the release of arsenic, a potent poison that disrupts cellular metabolism.
**Why the Correct Answer is Right**
The primary mechanism of action of Paris green involves the release of inorganic arsenic (As(III)), which then gets converted to the more toxic As(V) form. This arsenic species binds to sulfhydryl groups on enzymes, thereby inhibiting cellular respiration and ultimately leading to cell death. The toxic effects of arsenic are mediated through the inhibition of several key enzymes, including glyceraldehyde 3-phosphate dehydrogenase and thioredoxin reductase.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because while Paris green does contain arsenic, the question seems to be asking for the specific entity or organism it kills. Arsenic is not a living entity.
**Option B:** Incorrect because the question is asking for the entity that Paris green kills, not a condition it causes or a symptom it produces.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that arsenic compounds like Paris green can cause severe and irreversible damage to the nervous system, skin, and gastrointestinal tract, even at low doses. The use of arsenic-based compounds has largely been discontinued due to their toxicity.
**Correct Answer: A. Arsenic.**