Question

Chemical mutagens are far more hazardous than radiations because

• A. The exposure to chemical is more prevalent.
• B. The organism possesses protection for radiation but no protection for chemicals.
• C. The chemically induced mutations are more deleterious.
• D. The chemicals are synthetic.

Answer 1

Answer: (B)

The organism possesses protection for radiation but no protection for chemicals.

• DNA is more prone to radiation exposure owing to use of electromagnetic devices and increasing greenhouse effect which makes option A incorrect.
• Chemical that can change the molecular structure of gene is called as chemical mutagen.
• It includes base analogues, nitrous acid, alkylating agents and dyes; they mutate the structure of nucleic acid in a way for which repair system is not available in organisms.
• On the other hand, radiations include ionizing and non-ionizing radiations that mostly after the chromosome morphology by substitution or frameshift mutations which are corrected by natural DNA repair mechanism (base excision, recombination etc.) and are turned less harmful than chemical mutagen for which no repair system is available; option B is correct.
• The radiations can directly affect the chromosomes due to their energy level and penetrance which makes them more deleterious than chemical mutagens; option C is incorrect
• Mutagenicity of a mutagen depends on its ability to affect the DNA; not on its being synthetic or natural.
• Correct answer is B.