NEETBotanyCell Cycle and Cell Division
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In meiosis, crossing over leads to the recombination of genetic material on the two homologous chromosomes. Reason (R): Crossing over is an enzyme-mediated process that occurs between sister chromatids of homologous chromosomes during the pachytene stage. In the light of the above statements, choos
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A)
- B(A) is true but (R) is false
- CBoth (A) and (R) are true but (R) is not the correct explanation of (A)
- D(A) is false but (R) is true
Correct answer
B. (A) is true but (R) is false
Step-by-step solution
Assertion (A) is true: As per NCERT, crossing over is the exchange of genetic material between two homologous chromosomes, which leads to the recombination of genetic material on the two chromosomes. Reason (R) is false: While crossing over is indeed an enzyme-mediated process (involving recombinase) that occurs during the pachytene stage, it takes place between NON-sister chromatids of the homologous chromosomes, not sister chromatids. Exchange between sister chromatids would not result in genetic recombination si