Describe the nucleosome. Be sure to include each type of histone and how many of
ID: 70821 • Letter: D
Question
Describe the nucleosome. Be sure to include each type of histone and how many of each type are found within the nucleosome. Nucleosomes can be organized into a relaxed or compact structure. Would a gene be more likely to be turned on if the chromatin is relaxed or compact? Why? Histone acetylation can affect the structure of chromatin. Will acetylation increase or decrease the expression of gene? Give you answer in terms of chromatin compaction. HDACs affect the acetylation of histones. Do they increase or decrease acetylation? A tumor suppressor has become silenced. Would an HDAC inhibitor or an HDAC activator be a good treatment option? Why?Explanation / Answer
1. The nucleosome is the fundamental subunit of chromatin. Chromatin structure is highly complex. DNA is wrapped around an octamer of histone proteins. Histone proteins not only keep the DNA in an organized form, but also regulate the gene expression. Every core histone protein has a tail, called the N-terminal tail. Five major families of histones are there: H1/H5, H2A, H2B, H3 and H4. Among them H2A, H2B, H3 and H4 are the core histones, while H1 and H5 are linker histones.
A. DNA is wrapped tightly around the histone octamer when chromatin is in compact state. Gene can be expressed when the chromatin is in relaxed state.
B. Histone acetylation removes the positive charge of the lysine residues, which normally attract negatively charged DNA; thus, reducing the interaction between DNA and histone proteins. This results in the formation of more relaxed structure of DNA, associated with greater level of DNA replication and transcription.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.