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Multiple Choice
A mutation has occurred that has made the uvrD gene nonfunctional. What effect will this have on damaged DNA?
A
The DNA will be unable to replicate, resulting in cell death.
B
The DNA will be unable to undergo nucleotide excision repair, leading to accumulation of DNA damage.
C
The DNA will undergo increased recombination, leading to genetic diversity.
D
The DNA will be repaired more efficiently, reducing mutation rates.
Verified step by step guidance
1
Understand the role of the uvrD gene: The uvrD gene encodes a helicase enzyme that is crucial for the nucleotide excision repair (NER) pathway in bacteria. This enzyme helps unwind the DNA double helix to allow repair proteins to access and remove damaged nucleotides.
Identify the process affected by the mutation: Since the uvrD gene is nonfunctional, the helicase activity required for NER is compromised. This means that the DNA cannot be properly unwound, hindering the repair process.
Consider the consequences of impaired NER: Without effective nucleotide excision repair, damaged DNA cannot be corrected. This leads to the accumulation of DNA lesions, which can interfere with replication and transcription, potentially causing cell death or malfunction.
Evaluate the options given: The correct answer is that the DNA will be unable to undergo nucleotide excision repair, leading to accumulation of DNA damage. This aligns with the role of uvrD in the NER pathway.
Reflect on the importance of DNA repair mechanisms: DNA repair is essential for maintaining genomic integrity. Mutations in repair genes like uvrD can have significant impacts on cell survival and function, highlighting the importance of these pathways in preventing genetic disorders and cancer.