Question

a sperm with two copies of chromosome 15 fertilizes a normal egg. the zygote will have a(n) ______ karyotype.
options:

• triploid
• aneuploid
• aneuploid and trisomy 21
• normal
• trisomy 21

Explanation:

A normal egg has 1 copy of each chromosome. The sperm has 2 copies of chromosome 15, so the zygote gets 3 copies of chromosome 15 (abnormal chromosome number for that pair). Aneuploidy refers to having an abnormal number of chromosomes for a specific pair, which matches this case. Triploid means 3 full sets of chromosomes (not just one pair), trisomy 21 is extra chromosome 21 (unrelated here), and normal is incorrect. Thus, the zygote is aneuploid.

Answer:

B. aneuploid