Sister Chromatids

Sister chromatids are identical copies of a single chromosome that are produced during the process of DNA replication, which occurs prior to cell division. Each chromosome consists of two identical sister chromatids that are held together by a protein complex called the centromere.

During DNA replication, the double-stranded DNA molecule is unwound and each strand is used as a template to synthesize a new complementary strand. The resulting two identical DNA molecules are then packaged into chromatin, which condenses further into the characteristic X-shape of a chromosome.

The two sister chromatids are held together at a region of the chromosome called the centromere, which serves as the attachment site for microtubules that help to move the chromosomes during cell division. Each sister chromatid contains a full copy of the genetic material that was present in the original chromosome, including all of the genes and regulatory elements.

Sister chromatids are important because they ensure that each daughter cell produced during cell division receives an identical copy of the genetic material. When the cell divides, the sister chromatids separate from each other and are pulled to opposite poles of the cell by the microtubules attached to the centromeres. Each daughter cell then receives one copy of each sister chromatid, resulting in two genetically identical cells. Let’s see some points about them:

• Structure: Sister chromatids are formed during the S phase of the cell cycle when DNA replication takes place. Each sister chromatid is composed of DNA and associated proteins.
• Number: Sister chromatids are formed from a single chromosome and are always found in pairs.
• Function: Sister chromatids are involved in the process of cell division, where they separate and are distributed to each of the daughter cells. This ensures that each daughter cell receives an exact copy of the chromosome, preserving the genetic information of the parent cell.

Homologous chromosomes and sister chromatids are two important components of cell replication and division. They play a critical role in the maintenance of genetic information and the formation of daughter cells. While both types of chromosomes are similar in structure, they are distinct and serve different purposes in the cell.