What is the consequence to a bacterial cell of a mutation that inactivates the enzyme responsible for methylating the A in the DNA sequence 5′ GATC?
A)Replication of the lagging strand cannot be completed.
B)Thymine dimers cannot be repaired.
C)Parental and new DNA strands cannot be distinguished during mismatch repair.
D)Expression of certain metabolic genes is decreased.
E)The mutation rate of all genes will be lower.

Question

Quizplus · Accepted Answer

The enzyme responsible for methylating the A in the DNA sequence 5′ GATC is involved in distinguishing between the parental and newly synthesized DNA strands during mismatch repair. Methylation marks the parental strand, allowing the repair systems to correct mismatches in the newly synthesized strand by using the methylated strand as the template. If this enzyme is inactivated, the cell cannot differentiate between the old and new strands, impairing the mismatch repair process.

What Is the Consequence to a Bacterial Cell of a Mutation