Question

Chromosomes replication occurs during ------.
A) S Phase
B) G2 Phase
C) Metaphase
D) Anaphase

Answer 1

Hint: Replication is the process by which a macromolecule molecule is duplicated. DNA replication is required before cellular division, ensuring that every cell contains a replica of the genome. In eukaryotes, chromosomal replication occurs within the nucleus, during the S phase of the cell cycle.

Complete answer:
Chromosome replication occurs during S Phase. The S phase of a cell cycle occurs during interphase, before mitosis or meiosis, and is liable for the synthesis or replication of DNA.
S phase (Synthesis Phase) is the phase of the cell cycle during which DNA is replicated, occurring between the G1 phase and G2 phase. Since accurate duplication of the genome is critical to successful cellular division, the processes that occur during S-phase are tightly regulated and widely conserved.
Entry into S-phase is controlled by the G1 restriction point (R), which commits cells to the rest of the cell-cycle if there's adequate nutrients and growth signaling. This transition is actually irreversible; after passing the restriction point, the cell will progress through S-phase albeit environmental conditions become unfavorable.
Accordingly, entry into S-phase is controlled by molecular pathways that facilitate a rapid, unidirectional shift in cell state. In yeast, as an example, cell growth induces accumulation of Cln3 cyclin, which is complexed with the cyclin dependent kinase CDK2.

Note:
After replication there are a complete 46 chromosomes, with 92 individual chromatids, in each cell. G2 Phase: During G2, the cell makes proteins that are utilized in cellular division. One among the proteins is going to be utilized in the formation of microtubules.