Question

exploring chromosomes and chromosom
read the article to learn more about the disorders
that can occur when there is an irregular number
of chromosomes.
human chromosomal disorders
explain how nondisjunction can lead to
aneuploidies.
done
intro
4 of 4

Explanation:

Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division (meiosis I or meiosis II). When this occurs, gametes (sperm or egg cells) can receive an extra chromosome (n + 1) or be missing a chromosome (n - 1). When these abnormal gametes fuse with a normal gamete (n) during fertilization, the resulting zygote will have an abnormal number of chromosomes (aneuploidy). For example, in Down syndrome (trisomy 21), nondisjunction leads to an extra copy of chromosome 21.

Answer:

Nondisjunction is the improper separation of chromosomes during meiosis. This results in gametes with an abnormal chromosome number (\(n + 1\) or \(n-1\)). When these gametes combine with a normal gamete (\(n\)) during fertilization, the zygote has aneuploidy (an abnormal chromosome count).