Telomeres on duplicated chromatids in prophase

Steps:

• Human body cells have 46 chromosomes in G1 phase.
• By prophase of mitosis, DNA replication creates 2 sister chromatids per chromosome, yielding 92 chromatids.
• Each chromatid is a linear DNA molecule with telomeres at both ends.
• Total telomeres: 92 chromatids × 2 ends each = 184.

Why D is correct:

• Telomeres protect the ends of linear chromosomes; each chromatid has two distinct ends requiring separate telomeres, as defined by chromosome structure.

Why the others are wrong:

• A: Underestimates by considering only 46 unduplicated chromosomes with one end each, ignoring replication and two ends.
• B: Counts only one telomere per chromatid, overlooking the second end.
• C: Incorrectly assumes 92 chromosomes instead of 46 duplicated into 92 chromatids.

Final answer: D