S Phase

Definition

S phase, also known as the synthesis phase, is a critical stage in the cell cycle where the cell's genetic material, or DNA, is replicated. During this phase, the cell prepares for cell division by ensuring that it has a complete and accurate set of chromosomes to pass on to the daughter cells.

5 Must Know Facts For Your Next Test

1. During S phase, the cell's DNA is replicated, ensuring that each daughter cell will receive a complete set of genetic material.
2. S phase is one of the four main stages of the cell cycle, along with G1, G2, and M (mitosis) phases.
3. The duration of S phase can vary depending on the cell type and the organism, but it typically lasts between 6 to 12 hours in human cells.
4. Accurate DNA replication during S phase is crucial for maintaining genetic stability and preventing the propagation of mutations to daughter cells.
5. Disruptions or errors in S phase can lead to genomic instability, which is a hallmark of many diseases, including cancer.

Review Questions

• Explain the significance of the S phase in the context of cell growth and division.
  • The S phase is a critical step in the cell cycle, as it is responsible for the replication of the cell's genetic material, or DNA. During this phase, the cell ensures that it has a complete and accurate set of chromosomes to pass on to the daughter cells during cell division. This process is essential for maintaining genetic stability and enabling the cell to divide and proliferate, which are fundamental aspects of cell growth and division.
• Describe the relationship between S phase and the other phases of the cell cycle.
  • The S phase is one of the four main stages of the cell cycle, which also includes G1, G2, and M (mitosis) phases. The cell cycle is a tightly regulated process that ensures the cell grows, replicates its DNA, and divides in a coordinated manner. S phase follows the G1 phase, where the cell prepares for DNA replication, and precedes the G2 phase, where the cell further prepares for cell division. The successful completion of S phase is a critical checkpoint, as it ensures the cell has the necessary genetic material to undergo mitosis and produce two genetically identical daughter cells.
• Analyze the potential consequences of errors or disruptions during the S phase of the cell cycle.
  • Disruptions or errors that occur during the S phase can have significant consequences for the cell and the organism as a whole. Inaccurate DNA replication can lead to the propagation of genetic mutations, which can contribute to genomic instability. This instability is a hallmark of many diseases, including cancer, where cells acquire genetic alterations that allow them to proliferate uncontrollably. Additionally, failures in the proper replication and segregation of chromosomes during S phase can result in aneuploidy, or an abnormal number of chromosomes, which can also be associated with various pathological conditions. Therefore, the faithful and accurate completion of the S phase is crucial for maintaining genetic stability and ensuring the proper growth and division of cells.

Related terms

Cell Cycle: The series of events that a cell goes through, including growth, DNA replication, and division, resulting in the production of two daughter cells.

Mitosis:

The process of cell division in which a single cell divides into two or more daughter cells, each with an identical set of chromosomes.

Interphase:

The period of the cell cycle between cell divisions, consisting of G1, S, and G2 phases, where the cell grows and prepares for division.