Telomeres on replicated chromosomes in metaphase

Steps:

• Diploid cell has 26 chromosomes (2n=26), replicated during metaphase into sister chromatids.
• Each linear chromosome has two ends, each capped by a telomere.
• Replication produces two sister chromatids per chromosome, each with two telomeres.
• Total telomeres: 26 chromosomes × 4 telomeres each = 104.

Why D is correct:

• In metaphase, each duplicated chromosome consists of two sister chromatids, each with two telomeres (one per end), yielding 4 per chromosome; 26 × 4 = 104 (definition of telomere as end-cap structures).

Why the others are wrong:

• A. 26: Assumes one telomere per unreplicated chromosome, ignoring two ends and replication.
• B. 52: Counts two telomeres per unreplicated chromosome, ignoring replication doubles chromatids.
• C. 78: Results from erroneous multiplication (e.g., 26 × 3), not matching chromosome structure.

Final answer: D