Question

At what stage of the cell life, are histone proteins synthesized in eukaryotic-cells?
A. During telophase
B. During S phase
C. During G2 stage of prophase
D. During entire prophase

Answer 1

Hint: This phase is occurring between the G1 and G2 phase.

Complete Answer:
Histones are the proteins that are composed of positively charged amino acid which includes lysine and arginine. By the help of electrostatic interactions, positively charged amino acids are associated with negatively charged DNA.
The DNA is present in the nucleus. Histone proteins are highly conserved proteins. There are five types of histone proteins namely (H1, H2A, H2B, H3 and H4).
The main function of histone is to regulate chromatin impact and compact DNA strands. The histone proteins are synthesized during the S phase of the cell life.
Due to the entry of the S phase, histone proteins get regulated at RNA level. This also increases transcription of histone genes. S phases are also called synthesis phases.
So, that's why histone proteins are synthesized in that phase only. Prophase is the first phase of mitosis and prophase is also the longest phase of the mitosis.

Thus, the correct answer is option B. i.e., During S phase.

Additional information: Telophase is the final phase in both meiosis and mitosis in the eukaryotic cells. It is the process that separates two genetic materials carried in the nucleus of a parent cell into two daughter cells. The last part of prophase is G2 phase.

Note: Histone proteins were first identified in the year 1964. S phase is also responsible for replication of DNA