Describe the changes occurring during synthesis phase.

Explanation

During this phase synthesis of DNA and replication of DNA take place and amount of DNA per cell doubles.
If the initial amount of DNA is denoted as 2C then it increases to 4C. However, there is no increase in the chromosome number.
If the cell had diploid or 2n number of chromosomes at G, phase, even after S-phase the number of chromosomes remains the same i.e. 2n.
Histone protein is synthesized.
In animal cells, during the S-phase, DNA replication begins in the nucleus and the centriole duplicates in the cytoplasm.