Question

A. Chromatin remodeling complexes act to regulate gene expression and other DNA processes that involve access to DNA. A characteristic component of chromatin remodeling complexes is a powerful ATPase. Why is ATPase activity needed? B. Imagine that you have developed a method to isolate all of the histones bound to a single human chromosome. You then examine histones from the inactive X chromosome in an individual female and compare them to histones from her active X chromosome. Do you think these two sets of histones will be the same? Explain.

Answer 1

ATPase activity in chromatin remodeling complexes provides the necessary energy for altering chromatin structure, thus regulating gene expression. Differences in histone modifications are expected between active and inactive X chromosomes, affecting the accessibility of DNA to transcription machinery.

Step-by-step explanation:

ATPase Activity in Chromatin Remodeling Complexes

Chromatin remodeling complexes are crucial for regulating gene expression as they enable the dynamic changes in chromatin structure that allow access to the DNA for transcription and other DNA processes. The ATPase activity is essential because it provides the energy required for the movement, sliding, and repositioning of nucleosomes. This energy-intensive process involves hydrolyzing ATP, which allows the chromatin structure to become more open or closed as needed for the regulation of gene expression.

Comparison of Histones from Active and Inactive X Chromosomes

When comparing histones from an inactive X chromosome to those from an active X chromosome, it is expected that there will be differences. The histones of the inactive X are likely to have chemical modifications that signal a tightly packed, heterochromatic structure, leading to gene silencing. Conversely, histones on the active X chromosome would have modifications like acetylation that result in a more open, euchromatic structure conducive to gene transcription.