Non-disjunction of the 21st pair of chromosomes in one of the gametes leads to 47 chromosomes in one individual. This condition is called
Correct answer: C. Down syndrome
- A. Turner's syndrome
- B. Klinefelter's syndrome
- C. Down syndrome
- D. Jacob's syndrome
Explanation
Down syndrome is usually caused by an error in cell division called "nondisjunction." Nondisjunction results in an embryo with three copies of chromosome 21 instead of the usual two. Before or at conception, a pair of 21st chromosomes in either the sperm or the egg fails to separate.
This question appeared on the UHS MDCAT 2014 paper, which you can sit online with every answer explained.
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About Chromosomes
Chromosomes are DNA-protein structures that carry genes and become visible during cell division. Coverage includes chromatin, centromeres, sister chromatids, homologous chromosomes, chromosome number, and the distinction between diploid and haploid cells, with links to DNA replication, mitosis and meiosis.
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More Chromosomes questions
The most critical phase of mitosis which ensures equal distribution of chromatids in the daughter cells is:
Down's syndrome is a result of non-disjunction of_ pair of chromosomes that fails to segregate:
In Down's syndrome, which one of the following pair of chromosome fails to segregate?
Typical symptoms like enlarged breasts and small testis in male are attributed to:
Turner's syndrome is characterized by having:
The disease in which an individual has extra sex chromosome (44 + XXY) is known as: