Choose the one most appropriate answer for each.
-Barr body
A)A condensed X chromosome
B)Protein that combines with DNA all along its length
C)Attaches or detaches from operator to regulate transcription
D)Portion of the operon that binds RNA polymerase
E)Genes that induce expression of other genes
F)Genes controlling the development of specific body parts
G)Mechanism of equalizing gene expression between the sexes
H)Binding sites on DNA for regulatory proteins that increase transcription rates

Question

Quizplus · Accepted Answer

A Barr body is a condensed, inactive X chromosome found in the cells of female mammals.

Answer: G
 The Barr body is a mechanism of equalizing gene expression between the sexes. Since females have two X chromosomes, one X chromosome in each cell is randomly inactivated to prevent overexpression of X-linked genes. This condensed, inactive X chromosome is called a Barr body.

Answer: H
 Binding sites on DNA for regulatory proteins that increase transcription rates are known as enhancers. These enhancers can be located upstream or downstream from the gene they regulate and can be bound by specific transcription factors to increase transcription rates.

Note: None of the other choices are correct. B refers to histones, C and D relate to operons and gene regulation in bacteria, E refers to regulatory genes, and F refers to homeotic genes.

Choose the One Most Appropriate Answer for Each