Question

in an otherwise normal cell, what happens if one mistake is made during dna replication?
○ nothing; mistakes just happen.
○ the cell will begin to divide uncontrollably, forming a malignant tumor.
○ a cell cycle checkpoint detects the error and pauses the cell cycle so the error can be corrected.
○ mistakes are never made during dna replication.
○ the mutation will be inherited by the individuals offspring.

Explanation:

• In normal cells, there are cell cycle checkpoints. These checkpoints monitor processes like DNA replication.
• If a mistake (error) is detected during DNA replication, the checkpoint pauses the cell cycle. This allows time for the error to be corrected.
• Option 1 ("Nothing; mistakes just happen") is incorrect as cells have mechanisms to deal with errors.
• Option 2 (uncontrollable division forming a malignant tumor) is an extreme outcome that usually doesn't occur from a single, correctable error in a normal cell.
• Option 4 ("Mistakes are never made...") is false as DNA replication is not perfect.
• Option 5 (mutation inherited by offspring) would be relevant if it were a germ - cell mutation, but the question doesn't specify that, and for a normal somatic cell, the mutation would not be passed to offspring.

Answer:

A cell cycle checkpoint detects the error and pauses the cell cycle so the error can be corrected.