PATHOLOGY MCQ
GENETICS AND DISEASE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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An individual has three number 21 chromosomes. Which is most likely the cause?
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disjunction
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crossing over
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gene mutation
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DNA replication
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Explanation:
Detailed explanation-1: -Trisomy 21. About 95 percent of the time, Down syndrome is caused by trisomy 21-the person has three copies of chromosome 21, instead of the usual two copies, in all cells. This is caused by abnormal cell division during the development of the sperm cell or the egg cell.
Detailed explanation-2: -In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
There is 1 question to complete.