G2 Phase

Definition

The G2 phase is the third stage of the cell cycle that occurs after DNA replication and before mitosis. During this phase, the cell prepares for division by undergoing critical processes such as repairing any DNA damage, synthesizing proteins, and ensuring that all cellular components are ready for mitosis. The G2 phase plays a key role in maintaining genetic integrity and allowing for proper cellular division.

5 Must Know Facts For Your Next Test

1. The G2 phase typically lasts several hours and is crucial for ensuring the cell is fully prepared for mitosis.
2. During the G2 phase, the cell undergoes a series of quality control checks, including verifying that DNA has been replicated accurately without damage.
3. Proteins required for mitosis, such as cyclins and cyclin-dependent kinases (CDKs), are synthesized during this phase to regulate progression into mitosis.
4. The G2/M checkpoint is a critical point where the cell checks for DNA damage and ensures all chromosomes are properly replicated before entering mitosis.
5. If issues are detected during the G2 phase, the cell may activate repair mechanisms or undergo apoptosis to prevent passing on damaged DNA.

Review Questions

• What are the primary functions of the G2 phase in the context of preparing for cell division?
  • The G2 phase primarily functions to prepare the cell for mitosis by checking for DNA integrity and synthesizing proteins essential for division. It ensures that any DNA damage is repaired and that all cellular components, like organelles and microtubules, are correctly positioned. This preparation is crucial for successful mitosis and prevents potential errors that could lead to issues in daughter cells.
• How do checkpoints during the G2 phase contribute to maintaining genetic stability during cell division?
  • Checkpoints during the G2 phase serve as regulatory points that assess whether the cell is ready to proceed to mitosis. These checkpoints evaluate factors like DNA damage and completeness of DNA replication. If abnormalities are detected, they halt progression into mitosis, allowing time for repair processes or triggering programmed cell death (apoptosis) if necessary, thereby maintaining genetic stability in daughter cells.
• Evaluate the importance of the G2/M checkpoint in relation to cancer development and treatment strategies.
  • The G2/M checkpoint is vital in preventing cells with damaged DNA from entering mitosis. If this checkpoint fails, it can lead to genomic instability, which is a hallmark of cancer development. Many cancer treatments target this checkpoint mechanism to induce cell death in cancerous cells by exploiting their inability to repair DNA damage effectively. Understanding how this checkpoint operates can lead to improved therapies that enhance treatment efficacy while minimizing harm to healthy cells.

Related terms

Cell Cycle: The series of stages that a cell goes through to grow and divide, including interphase (G1, S, G2) and mitotic phase (mitosis and cytokinesis).

Checkpoint: Regulatory points within the cell cycle that assess whether a cell is ready to proceed to the next phase, preventing errors in division.

Mitosis: The process of nuclear division that results in two genetically identical daughter cells, following the G2 phase.