Question

in an otherwise normal cell, what happens if one mistake is made during dna replication?
the mutation will be inherited by the individuals offspring.
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.
nothing; mistakes just happen.

Explanation:

• In a normal cell, DNA replication errors are usually detected by cell cycle checkpoints. These checkpoints pause the cell cycle to allow for error correction.
• For the first option, a single mistake in a normal cell (not a germ - cell) won't be inherited by offspring.
• A single mistake doesn't lead to uncontrollable division (that requires multiple mutations in oncogenes and tumor - suppressor genes).
• Mistakes do occur during DNA replication, so the fourth option is wrong. And "nothing" is incorrect as cells have repair mechanisms.

Answer:

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