17_The Histone Code

Question 1

How many core histones are present in a nucleosome?

Answer 1

8

Question 2

How many turns of DNA travel around one nucleosome?

Answer 2

1.8

Question 3

Which histones are found in the nucleosome core? how about on the outside?

Answer 3

core: 2 each of H2A, H2B, H3, H4
outside: H1

Question 4

What sticks out of each histone in the core (past the DNA in the nucleosome)?

Answer 4

a flexible amino terminal tail

Question 5

What do histone modifications collectively create?

Answer 5

The histone code

Question 6

What are some types of histone modifications?

Answer 6

phosphorylation, acetylation, methylation, ubiquitination

Question 7

What do histone modifications serve as docking sites for?

Answer 7

non-histone proteins

Question 8

DNA methylation is associated with (closed/open) chromatin.

Answer 8

closed

Question 9

DNA acetylation is associated with (closed/open) chromatin.

Answer 9

open

Question 10

What modification does HP1 bind to?

Answer 10

methylated Lys-9 of H3

Question 11

Recruitment of HP1 is associated with (closed/open) chromatin.

Answer 11

closed

Question 12

What is the part of HP1 used to bind methylated histones called?

Answer 12

the chromodomain

Question 13

As development and differentiation proceed, which types of genes remain on in specialized cell?

Answer 13

cell-type specific and general-function genes

Question 14

How does the histone code of amino acid residue modifications control chromatin state?

Answer 14

histone code recruits non-histone proteins that dictate chromatin state

Question 15

Do small RNA molecules contribute to the histone code?

Answer 15

yes