If the radiation exposure occurs before DNA synthesis, the damage manifests:: (A) One arm of chromosome, (B) Both the arms of chromosome, (C) Shorter arm of chromosome, (D) None of the arm of chromosome is affected
Answer is B. If radiation exposure occurs after DNA synthesis (i.e., in G2 or mid and late S), only one arm of the affected chromosome is broken.
If radiation induced break occurs before DNA has replicated (i.e., in G1 or early S), the damage manifests in both arms (Chromosome aberration) at the next mitosis.