Included in the entry for ‘interphase’ is the statement: “During G2 the mitotic spindle is formed.” This statement: .
a) Is accurate
b) Is accurate but incomplete, as it doesn’t account for d
c) Is inaccurate
d) None of the above
The Correct Answer and Explanation is :
The statement “During G2 the mitotic spindle is formed” is (c) inaccurate. Here’s a detailed explanation:
Understanding Interphase and the Cell Cycle:
Interphase is the phase of the cell cycle during which the cell prepares for mitosis. It is subdivided into three stages: G1 (Gap 1), S (Synthesis), and G2 (Gap 2). During G1, the cell grows and synthesizes proteins required for DNA replication. In the S phase, DNA is replicated, resulting in two sets of chromosomes. G2 is the final stage of interphase, where the cell continues to grow and prepare for mitosis.
Formation of the Mitotic Spindle:
The mitotic spindle is crucial for chromosome separation during mitosis. However, the formation of the mitotic spindle primarily occurs during prophase, which is the first stage of mitosis, not during the G2 phase. In G2, the cell undergoes preparatory processes, such as checking for DNA damage and ensuring all cellular components are ready for division, but the actual assembly of the spindle apparatus begins as the cell enters mitosis.
Key Processes in G2:
During G2, several critical events occur:
- Checkpoint Activation: The cell assesses its DNA for damage and checks whether it has completed DNA replication accurately.
- Protein Synthesis: Specific proteins needed for mitosis, including those that will later form the spindle fibers, are synthesized.
- Centrosome Duplication: The centrosomes, which will organize the mitotic spindle, are duplicated and move to opposite poles of the cell.
Conclusion:
The statement about spindle formation in G2 overlooks the critical detail that spindle assembly and function occur during mitosis. Therefore, the correct understanding is that the mitotic spindle is not formed during G2 but rather begins to form at the onset of prophase, making the original statement inaccurate.