Question

5. Explain the process that allows two sister chromatids to be formed from a single chromosome. . I need this answer explained in detail Could you please do it for me?

Thanks.

Answer 1

During cell division from a single cell two daughter cells are formed. ( for your understanding only- If the cell contain 2n number of chromosomes , before undergoing cell divison the 2n become 4n (in s phase), then 4n is partioned into 2 daughter cells as 2n s)

DNA is duplicated during S phase (of interphase) before entering into mitosis.Thus two daughter DNA strands are produced from one chromosomal DNA. These daughter strands recruit additional histones and other proteins to form the sister chromatids. Thus sister chromatids are two identical copies of the same chromosome (which are connected by a centromere, cohesin protein help the sister chromatids to be glued together) formed by DNA replication.During cell division in anaphase stage, the sister chromatids seperate ,a major reason for chromatid separation is the degradation of the cohesin molecules by protease separase and each cell recieve one copy of the DNA or chromosome. Upon separation, every chromatid becomes an independent chromosome. Thus formation of sister chromatid will help to maintain the genetic content across generations.

IN s phase you can see 2 chromosome one red and one blue. red chromosome contain two sister chromatid both are red coloured joined at centromere, blue chromosome contain 2 sister chromatids similarly. (number of  red chromosome = 1, number of DNA in red chromosome= 2, number of sister chromatid in red chromosome= 2)