A Levels Biology (9700)•9700/12/M/J/18
Explanation
Telomeres shorten with mitotic divisions
Steps:
- Telomere consists of TTAGGG repeats, each 6 bases long.
- During mitosis, telomeres shorten slightly due to the end-replication problem.
- More divisions result in greater shortening and fewer total bases.
- Smallest base count (5548) indicates most divisions.
Why A is correct:
- Shortest telomere (5548 bases) reflects maximum erosion from repeated divisions, per the end-replication mechanism.
Why the others are wrong:
- B (5590): Longer than A, so fewer divisions.
- C (5645): Even longer, indicating fewer divisions than A or B.
- D (5700): Longest, from the fewest divisions.
Final answer: A
Topic: Replication and division of nuclei and cells
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