Question

DNA and histone proteins are synthesized during which of the following phases of cell cycle?
A. S phase
B. G2 phase
C. G1 phase
D. None of these.

Answer 1

Hint: In is the phase of the cellar cycle wherein DNA is replicated, going on among G1 segment and G2 segment. Since correct duplication of the genome is important to a success cell dividing, the techniques that arise in the course of this segment are tightly regulated and broadly conserved.

Complete answer:
To answer this question, first, we need to know about cell division. In unicellular organisms, cellar division is the manner of reproduction; in multicellular organisms, it's far the way of tissue development and maintenance. Survival of the eukaryotes relies upon interactions among many cell sorts, and it's far important that a balanced distribution of kinds be maintained. This is carried out with the aid of using the specially regulated technique of cellular proliferation. The development and separation or dividing of various cell populations are regulated in special ways, however the fundamental mechanisms are comparable at some stage in multicellular organisms.
Now, let us find the solution from the option.
S section is the synthesis segment of the cellar cycle. It is characterised with the aid of using a synthesis of histone proteins and replication of DNA of a chromosome. This protein enables withinside the formation of cellular systems like spindle fibre which in addition enables cell dividing.
During the G2 among DNA synthesis and mitosis, the cell will keep growing and convey new proteins. At the stop of this hole is some other managed checkpoint (G2 Checkpoint) to decide if the cell can now continue to go into M (mitosis) and divide. So on this segment DNA and histone protein aren't synthesized.
Cells growth in length in Gap 1, produce RNA and synthesize protein. A vital cell cycle management mechanism activated in the course of this period (G1 Checkpoint) guarantees that the whole thing is prepared for DNA synthesis.

Hence, the correct answer is option (A)

Note: In S phase, the cell synthesizes a whole reproduction of the DNA in its nucleus. It additionally duplicates a microtubule-organizing shape known as the centrosome. The centrosomes assist separate DNA in the course of M section.