Question

A model cell with damaged DNA was created to explain the importance of checkpoints in a cell cycle. The G2 checkpoint accidentally failed to work during experimentation. What do you think is the likely consequence of this failure?

Answer 1

Answer:

The failure of G₂ check-point would not have any critical consequences in this case as the model cell with damaged DNA would not enter the S phase due to the presence of G₁ check-point.

The cell cycle is mainly regulated by three check-points namely: G₁ check-point, G₂ check-point, and M check-point.

The G₁ check-point checks the cell for its size, nutrients availability, growth factors, and DNA damage.

• Once all conditions are favorable (such as appropriate size, energy reserves etc) the cell passes the G₁ check-point and progress to S phase of the cell cycle.
• In case of unfavorable condition the cell cycle halts or it may enter in G₀ phase again.
• If DNA damage is found then cell either goes for DNA repair or apoptosis if it could not be repaired.

The G₂ check-point checks the cell for its size, protein reserve, and accuracy of duplication of DNA or chromosomes (taken place in S phase). Only after passing this check-point, the cell enters the M or mitotic phase.

The M check-point checks if all the sister chromatids are properly attached to the spindle microtubules or not.