Of these answer choices, which could be the cause of Down syndrome for an offspring?

A. The mother's egg contained 22 chromosomes.

B. The father's sperm contained 23 chromosomes.

C. The mother's egg and the father's sperm each contained 23 chromosomes.

D. The father's sperm contained 23 chromosomes and the mother's egg contained 24 chromosomes.

Question

Heather Hayden

Biology

15 May, 11:03

Of these answer choices, which could be the cause of Down syndrome for an offspring?

A. The mother's egg contained 22 chromosomes.

B. The father's sperm contained 23 chromosomes.

C. The mother's egg and the father's sperm each contained 23 chromosomes.

D. The father's sperm contained 23 chromosomes and the mother's egg contained 24 chromosomes.

+5

Answers (1)

Know the Answer?

Edwin Tyler · Answer 1

Answer: D). The father's sperm contained 23 chromosomes and the mother's egg contained 24 chromosomes.

Explanation: Down syndrome is a chromosomal disorder caused by an extra chromosome. Each gamete (sperm cells and egg cells) contains 23 chromosomes. During fertilization, a sperm cell with 23 chromosomes fuses with an egg with 23 chromosomes to form a zygote with 46 chromosomes. A normal child has 46 chromosomes but a child with down syndrome has 47 chromosomes. A child with down syndrome has an extra chromosome usually inherited from the mother, that is the mother's egg contains 24 chromosomes instead of 23 chromosomes.