Question

when a child is born with down syndrome, when did the mutation occur?
a. during meiosis
b. during mitosis
c. during translation
d. during transcription

Explanation:

Down - syndrome is caused by an extra copy of chromosome 21. This usually occurs due to non - disjunction during meiosis in the formation of gametes (sperm or egg cells), resulting in a gamete with an extra chromosome 21. When this abnormal gamete fuses with a normal gamete during fertilization, the resulting zygote has three copies of chromosome 21. Mitosis is cell division for growth and repair in somatic cells, translation is the process of protein synthesis from mRNA, and transcription is the synthesis of mRNA from DNA, none of which are directly related to the chromosomal abnormality in Down - syndrome.

Answer:

A. During meiosis