Although the Most Frequent Forms of Down Syndrome Are Caused

question 30

Multiple Choice

Although the most frequent forms of Down syndrome are caused by a random error,nondisjunction of chromosome 21,Down syndrome occasionally runs in families.The cause of this form of familial Down syndrome is ________.

• A) an inversion involving chromosome 21
• B) a chromosomal aberration involving chromosome 1
• C) too many X chromosomes
• D) a translocation between chromosome 21 and a member of the D chromosome group
• E) a maternal age effect

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Definitions:

Chloroplasts

Organelles found in plant and algal cells where photosynthesis takes place, converting light energy into chemical energy stored in glucose.

Linear Chromosomes

Chromosomes that are structured as a series of linear sequences of DNA, typical in eukaryotic cells.

Domain Eukarya

One of the three domains of life, consisting of organisms with complex cells containing a nucleus.

Cell Wall

A rigid layer that lies outside the cell membrane of the cells of plants, fungi, and bacteria, providing structural support and protection.