Final answer:
In the cell cycle's S phase, DNA is replicated, resulting in 92 sister chromatids from 46 chromosomes in humans, all assembled for the subsequent process of mitosis. These sister chromatids are later separated into two new cells during cell division.
Step-by-step explanation:
Chromosome and Chromatid Numbers During the Cell Cycle Phases
During the cell cycle, a cell undergoes a series of phases culminating in cell division. The synthesis phase, or S phase, is a crucial part of the cycle, where DNA replication occurs. After this phase, each chromosome consists of two sister chromatids connected at the centromere, doubling the number of chromatids in the cell. This period of growth and preparation for division is followed by mitosis, where these sister chromatids are separated into two new cells.
In humans, the S phase yields 92 chromatids from the original 46 chromosomes. The G2 phase, following the S phase, sees the synthesis of proteins, such as tubulins and cohesin, vital for condensing chromatin and facilitating the mitotic process. The centrosomes are also duplicated during the S phase, contributing to the formation of the mitotic spindle. All these processes are geared towards ensuring successful division and the distribution of chromosomes into daughter cells during mitosis.
It is important not to confuse a pair of sister chromatids with a homologous pair of chromosomes, which are genetically similar but not identical, as they are inherited from different parents. The accurate management of chromosomes and chromatids during the cell cycle is imperative for the maintenance of genetic stability.