Q112 · Practice questionComplex familiar1 mark
QUESTION 112
For one chromosome pair, a meiosis produces four gametes: two contain both homologues and two contain neither. No other error occurs. The most likely error is
(A)
normal crossing over in prophase I.
(B)
failure of DNA replication before meiosis.
(C)
non-disjunction in only one meiosis-II daughter cell.
(D)
non-disjunction of the homologues in meiosis I.
WORKED SOLUTION
1 markAnswer D
Answer
D
Working
Failure of the homologous chromosomes to separate in meiosis I produces two n+1 and two n−1 gametes after normal meiosis II. A single meiosis-II error instead leaves two normal gametes.
Marking criteria
- Select D. [1 mark]
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
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