Question

25. Which one of the following is NOT considered a core histone protein? a. Hi b. H2B c. H3 d. H4 Short answers 1. You plan to identify mutations that arrest the cell cycle at the GI/S transition. Choose a model system and design an experiment that would accomplish this. Be specific. (10 points)

Answer 1

ANS (25)- H 1 protein is not the core histone protein.

EXPLANATION--> Histone octamer is the protein complex involves in DNA packaging of the cell, there is 5 type of  histone proteins H1/ H5 , H2A ,H2B, H3 and H4, They are composed of their two copies for the formation of complete octamer complex.

HISTONE work for the packaging of DNA------> The negatively charged DNA wrapped around a positively charge histone octamer complex and the linker histones binds to the entry / exit sites of DNA on the core to prevent it from un-packaging.

• H2A, H2B ,H3 and H4 are the histones involved in the formation of core of histone complex.
• H1 and H5 are the linker histone that prevents the opening/ un-packaging of DNA from the core.