Question

a cell contains dna damage that causes it to undergo apoptosis before reaching mitosis. this cell had twice the amount of dna for a cell of this type. during which checkpoint did this cell trigger apoptosis? (1 point) g₁ checkpoint g₂ checkpoint m checkpoint no checkpoint meets these criteria.

Explanation:

• G₁ Checkpoint: Checks for cell size, nutrients, growth factors, and DNA damage. If DNA is damaged, cell may enter G₀ (quiescent) or undergo apoptosis. But at G₁, DNA content is normal (not twice the amount yet as DNA replication occurs in S - phase).
• G₂ Checkpoint: Occurs after S - phase (where DNA replication takes place). At G₂, the cell has twice the amount of DNA (after replication in S). It checks for DNA damage and completeness of DNA replication. If there is DNA damage at this stage, the cell can undergo apoptosis.
• M Checkpoint: Checks for chromosome attachment to the spindle fibers. It is during mitosis (M - phase) and not related to the amount of DNA in the sense of having twice the amount due to replication (its main concern is chromosome - spindle attachment).

Answer:

G₂ Checkpoint