NEET Botany Cell Division MCQ Question

The G₀ phase, also known as the resting phase, is a stage in the cell cycle where cells exit the cycle and enter a quiescent state. This phase can be temporary or permanent, depending on the cell type and environmental conditions. Let’s analyze each option to determine which statement is incorrect.

Explanation of Each Option:

A) Mitosis occurs after G₀ phase.

• Explanation: This statement is incorrect. Cells in the G₀ phase have typically exited the cell cycle and do not immediately prepare for mitosis. While some cells can re-enter the cell cycle from G₀ and then proceed to mitosis (M phase), this is not a universal property of all cells in G₀. Many cells, such as neurons and muscle cells, remain in G₀ permanently and do not undergo mitosis. Thus, the presence of mitosis directly after G₀ is not guaranteed and can lead to misinterpretation of the cell cycle's flow.

B) Biocatalysts can be used to exit G₀ phase.

• Explanation: This statement is generally considered correct. Biocatalysts, such as certain growth factors and hormones, can stimulate cells to re-enter the cell cycle from the G₀ phase. For example, fibroblast growth factor (FGF) can promote cell division by moving cells out of G₀ and into the G₁ phase. Thus, it is possible for external biochemical signals to influence a cell’s ability to exit G₀.

C) Cell volume keeps on increasing during this phase.

• Explanation: This statement is also correct. During the G₀ phase, cells can continue to carry out metabolic processes, leading to an increase in cell size. Cells may accumulate nutrients and increase their cytoplasmic volume while remaining metabolically active, even if they are not dividing.

D) Cell metabolism occurs continuously in G₀ phase.

• Explanation: This statement is accurate as well. Cells in G₀ are not completely inactive; they continue to perform essential metabolic functions. This can include protein synthesis, energy production, and other cellular processes necessary for maintaining cellular health and function.

Summary of Correctness:

• Correct Answer: A is incorrect because not all cells in G₀ undergo mitosis immediately after exiting this phase.
• Other Options: B, C, and D are correct statements about the G₀ phase.

Key Concepts:

• The G₀ phase is a specialized state where cells are in a quiescent form and can be influenced by external signals to re-enter the cell cycle.
• Mitosis (M phase) is the process of cell division that occurs after the cell has completed the G1, S, and G2 phases, but not all cells in G₀ will enter this phase.
• Cell metabolism and growth can continue during G₀, but the cell is not preparing for division.

This understanding is crucial for cell biology, particularly in the context of how different cell types respond to environmental stimuli and growth factors.