Question

Which one of the following statements about the G1 checkpoint of eukaryotic cell division cycle is INCORRECT?

• A. Cell assures the existence of favorable extracellular environment
• B. Cell assures the DNA has no damage
• C. Cell assures the damaged DNAs are directed for repair mechanism
• D. Cell assures complete replication of DNA

Answer 1

The Correct Option is D

The question asks which statement about the G1 checkpoint of the eukaryotic cell division cycle is incorrect. To answer this question, we should first understand the role of the G1 checkpoint.

The G1 checkpoint, also known as the Restriction Point, is key in determining whether a cell proceeds through the cell cycle. It checks for:

1. Favorable Extracellular Environment: The cell ensures that the conditions outside are suitable for cell division, such as the availability of nutrients and proper growth signals.
2. DNA Damage: The cell checks for any damage to the DNA. If DNA damage is detected, the cell cycle is halted for repairs, preventing the propagation of damaged DNA.
3. Cell Size: The cell confirms adequate growth to support division.

Examining the given options:

• Cell assures the existence of favorable extracellular environment: This is correct, as explained above.
• Cell assures the DNA has no damage: This is correct. DNA damage detection is a crucial function of the G1 checkpoint.
• Cell assures the damaged DNAs are directed for repair mechanism: This is correct. If the checkpoint detects DNA damage, it initiates repair mechanisms.
• Cell assures complete replication of DNA: This option is incorrect for the G1 checkpoint. The replication of DNA is actually checked at the G2 checkpoint, not G1. The G2 checkpoint ensures that DNA replication is complete and that the replicated DNA is not damaged before the cell proceeds to mitosis.

Therefore, the statement "Cell assures complete replication of DNA" is the incorrect statement about the G1 checkpoint in the context of eukaryotic cell division.