Question 1: Which of the following insecticides is a natural contact poison?
- A. Propoxur
- B. Rotenone (Correct Answer)
- C. Carbaryl
- D. Lindane
Explanation: ***Rotenone***
- **Rotenone** is a naturally occurring plant-derived insecticide, traditionally used as a **contact poison** and **stomach poison**.
- It is effective against a broad spectrum of insects and works by inhibiting **electron transport** in the mitochondria, disrupting cellular respiration.
*Propoxur*
- **Propoxur** is a **synthetic carbamate insecticide**, not a natural one.
- It acts primarily as a **cholinesterase inhibitor**, interfering with nervous system function.
*Carbaryl*
- **Carbaryl** is a **synthetic carbamate insecticide**, derived from carbamic acid, not a natural product.
- Its mechanism of action involves **reversible inhibition of acetylcholinesterase**, leading to nerve overstimulation.
*Lindane*
- **Lindane** is an **organochlorine insecticide**, which is a synthetic compound, not naturally occurring.
- It acts as a **neurotoxin**, primarily by interfering with **GABA-gated chloride channels** in the insect's nervous system.
Question 2: Exposure to gases is a common hazard in industries. The gases can be classified as simple asphyxiants, chemical asphyxiants and anaesthetic gases. Which among the following are chemical asphyxiating gases ?
1. Carbon monoxide
2. Chloroform
3. Cyanide gas
4. Hydrogen
Select the correct answer using the code given below :
- A. 2 and 4
- B. 1 and 3 (Correct Answer)
- C. 1 and 4
- D. 2 and 3
Explanation: ***1 and 3***
- Both **carbon monoxide** and **cyanide gas** are classic examples of chemical asphyxiants.
- They interfere with the body's ability to utilize oxygen, leading to **cellular hypoxia** despite adequate tissue perfusion.
*2 and 4*
- **Chloroform** is an anesthetic and hepatotoxin, not primarily an asphyxiant.
- **Hydrogen** is a simple asphyxiant but does not have the chemical asphyxiant properties of carbon monoxide or cyanide.
*1 and 4*
- While **carbon monoxide** is a chemical asphyxiant, **hydrogen** is a simple asphyxiant that displaces oxygen without directly interfering with cellular respiration.
- The question implies a focus on gases that chemically interfere with oxygen utilization.
*2 and 3*
- **Cyanide gas** is an asphyxiant, but **chloroform** is an anesthetic and can cause central nervous system depression and organ toxicity.
- Chloroform's mechanism of action is distinct from the cellular hypoxia caused by asphyxiants.