Question

In which stage of the cell cycle are histone proteins synthesised in an eukaryotic cell ?
a. G2 stage of prophase
b. S-phase
c. Entire prophase
d. Telophase.

Answer 1

Histone proteins are the basic proteins which are rich in amino acids such as lysine and arginine, usually found in the nuclei of Eukaryotic cells which are packed and form the structural units nucleosomes, this proteins are synthesised in s-phase of cell cycle.

**Complete answer :** Cell cycle of Eukaryotic cells are divided into four phases such as G1, S, G2 and M
G1 and G2 are the check phases and S phase is synthesis phase and M phase is the mitosis phase
Before synthesis the cell will go through the first check phase called G1 phase and another check called G2 phase occurs before entering into mitosis, the phases G1, S and G2 are considered as interphase of cell cycle. It occurs before the mitosis for the synthesis or replication of DNA. This phase occurs both in mitosis and meiosis, where the genetic material of the DNA is doubled which will help to allow the enough amount of genetic material to be split into daughter cells.
The other options given in the question are
G1 phase which is considered as check phase or gap phase which is sub phase or part of interphase where cell growth occurs
Prophase and Telophase are the stages of mitosis where in prophase cell structure division started and preparation for division such as formation of spindles all takes place, whereas in Telophase almost cell divided and cytokinesis of cell takes place
So from the above explanation histone proteins are synthesised during the S phase of cell cycle.

Note: S in s-phase stands for synthesis, where all genetic material synthesis and DNA replication occurs during this phase and all material gets doubled. P16 is a very important protein during S-phase which is responsible for suppressing tumors during Synthesis in this phase.