Sister Chromatids

Definition

Sister chromatids are the two identical copies of a chromosome that are formed during the process of DNA replication in the cell cycle. They are joined together at a structure called the centromere and are crucial for the accurate segregation of genetic material during cell division.

5 Must Know Facts For Your Next Test

1. Sister chromatids are formed during the S phase of the cell cycle, when the DNA is replicated.
2. The two sister chromatids are genetically identical, as they contain the same genetic information.
3. Sister chromatids are crucial for the accurate segregation of chromosomes during cell division, ensuring that each daughter cell receives a complete set of genetic material.
4. The sister chromatids are held together by a protein complex called cohesin, which is gradually removed during the cell division process.
5. The separation of sister chromatids, known as sister chromatid separation, is a critical step in the cell division process and is regulated by various cellular mechanisms.

Review Questions

• Describe the role of sister chromatids in the cell cycle and cell division.
  • Sister chromatids are formed during the S phase of the cell cycle when the DNA is replicated. They are genetically identical copies of a chromosome that are joined together at the centromere. During cell division, the sister chromatids must be accurately segregated to ensure that each daughter cell receives a complete set of genetic material. The separation of sister chromatids is a crucial step in the cell division process and is tightly regulated by cellular mechanisms to maintain genomic integrity.
• Explain the relationship between sister chromatids and the centromere, and how this relationship is important for chromosome segregation.
  • The sister chromatids are joined together at a specialized region of the chromosome called the centromere. The centromere is where the spindle fibers attach during cell division, allowing for the accurate segregation of the sister chromatids to the daughter cells. The cohesion between the sister chromatids, mediated by the cohesin protein complex, is crucial for maintaining their attachment until they are properly aligned on the mitotic spindle. The separation of the sister chromatids, facilitated by the gradual removal of the cohesin complex, ensures that each daughter cell receives a complete set of genetic material.
• Analyze the importance of the accurate segregation of sister chromatids during cell division and the potential consequences of errors in this process.
  • The accurate segregation of sister chromatids during cell division is essential for maintaining genomic integrity and ensuring that each daughter cell receives a complete and identical set of genetic material. Errors in the separation of sister chromatids, such as chromosomal non-disjunction or lagging chromosomes, can lead to aneuploidy, where daughter cells receive an incorrect number of chromosomes. Aneuploidy can have severe consequences, including developmental abnormalities, genetic disorders, and the development of cancer. The cell has evolved various mechanisms, such as the spindle assembly checkpoint, to ensure the proper alignment and separation of sister chromatids to prevent such errors and maintain genomic stability.

Related terms

Chromosome:

A chromosome is a long, thread-like structure found in the nucleus of a cell that carries the genetic information in the form of genes.

DNA Replication: DNA replication is the process by which a DNA molecule is copied to produce two identical DNA molecules, ensuring that genetic information is passed on to daughter cells during cell division.

Centromere: The centromere is a specialized region of a chromosome where the sister chromatids are joined together and where spindle fibers attach during cell division.