Taq polymerase, isolated from Thermus aquaticus, is used in PCR. It lacks 3' to 5' exonuclease proofreading activity. What is a direct consequence of this property?
- A It cannot synthesize DNA at temperatures above 72 degrees Celsius
- B It requires an RNA primer to initiate DNA synthesis
- C It has a higher error rate compared to proofreading DNA polymerases ✓
- D It cannot amplify DNA fragments longer than 100 base pairs
Correct answer: C. It has a higher error rate compared to proofreading DNA polymerases
Explanation
Without 3' to 5' exonuclease proofreading activity, misincorporated nucleotides are not removed, resulting in a higher error rate (approximately 1 error per 10^4 bases). Taq polymerase is thermostable and functions at 72 degrees Celsius, can use DNA primers, and can amplify fragments several kilobases long.
Reference: Molecular Cloning: A Laboratory Manual, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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