AP BIOLOGY

Detailed explanation-1: -While most DNA replicates with fairly high fidelity, mistakes do happen, with polymerase enzymes sometimes inserting the wrong nucleotide or too many or too few nucleotides into a sequence. Fortunately, most of these mistakes are fixed through various DNA repair processes.

Detailed explanation-2: -Most of the mistakes during DNA replication are promptly corrected by DNA polymerase by proofreading the base that has been just added (Figure 14.6. 1). In proofreading, the DNA pol reads the newly added base before adding the next one, so a correction can be made.

Detailed explanation-3: -During DNA synthesis, most DNA polymerases “check their work, ” fixing the majority of mispaired bases in a process called proofreading. Immediately after DNA synthesis, any remaining mispaired bases can be detected and replaced in a process called mismatch repair.

Detailed explanation-4: -Mutations can occur for many reasons. For example, DNA mutations can be caused by mistakes made by the DNA polymerase during replication. As noted in chapter 9, DNA polymerases are highly processive enzymes that contain proofreading and editing functions.

Detailed explanation-5: -Answer and Explanation: DNA polymerase does not catch and correct every replication error. However, DNA polymerase has a very high fidelity rate.