Textbook Question
Answer the following questions concerning the accuracy of DNA polymerase during replication.
Identify two mechanisms that can correct the kind of abnormality resulting from the circumstances identified in part (c).
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17. Mutation, Repair, and Recombination
DNA Repair
2:26 minutesProblem 13c
Textbook Question
Answer the following questions concerning the accuracy of DNA polymerase during replication.
If a replication error escapes detection and correction, what kind of abnormality is most likely to exist at the site of the replication error?
Verified step by step guidance1
Understand the role of DNA polymerase in replication: DNA polymerase is responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strand. It also has proofreading activity to correct errors during replication.
Recognize what happens when an error escapes proofreading: If DNA polymerase fails to detect and correct an error, the incorrect nucleotide remains incorporated into the newly synthesized DNA strand.
Identify the type of abnormality caused by the error: The most likely abnormality at the site of replication error is a mismatch between the base pairs. For example, instead of the correct pairing (e.g., adenine with thymine), there may be an incorrect pairing (e.g., adenine with cytosine).
Consider the consequences of the mismatch: This mismatch can lead to a point mutation if the error is not corrected before the next round of replication. A point mutation is a permanent change in the DNA sequence at a single nucleotide position.
Understand the potential impact of the mutation: Depending on the location of the mutation, it may alter the coding sequence of a gene, potentially leading to changes in the protein product or regulatory regions, which can affect gene expression.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
DNA Polymerase Function
DNA polymerase is an enzyme responsible for synthesizing new DNA strands by adding nucleotides complementary to the template strand during replication. It also has proofreading capabilities, allowing it to detect and correct errors in the newly synthesized DNA. However, if an error escapes this proofreading process, it can lead to mutations in the DNA sequence.
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Replication Errors
Replication errors occur when DNA polymerase incorporates incorrect nucleotides into the growing DNA strand. These errors can arise from various factors, including chemical damage to DNA or mispairing of bases. If not corrected, these errors can result in permanent changes to the DNA sequence, potentially leading to abnormal protein function or disease.
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Types of Mutations
Mutations are changes in the DNA sequence that can arise from replication errors. The most common types include point mutations, which involve a single nucleotide change, and insertions or deletions, which can alter the reading frame of the genetic code. These mutations can have varying effects on an organism, ranging from benign to harmful, depending on their nature and location within the genome.
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