PCR is used to _____.

• A. Amplify a single gene or small sequence of DNA.
• B. Create DNA without introns.
• C. Insert foreign DNA into a host cell where it can be replicated.
• D. Cut segments of DNA creating complimentary sticky ends.
• E. None of these.

Answer: (A)

Verified step by step guidance

1. Understand the purpose of PCR (Polymerase Chain Reaction): PCR is a technique used in molecular biology to amplify a single or a few copies of a segment of DNA, generating thousands to millions of copies of a particular DNA sequence.
2. Analyze the options provided: The options include amplifying DNA, creating DNA without introns, inserting foreign DNA into a host cell, cutting DNA segments, and none of these.
3. Relate the purpose of PCR to the options: PCR is specifically designed to amplify DNA sequences, which means it makes many copies of a specific DNA segment.
4. Eliminate incorrect options: Creating DNA without introns, inserting foreign DNA, and cutting DNA are not functions of PCR. These are related to other techniques like reverse transcription, transformation, and restriction enzyme digestion, respectively.
5. Conclude with the correct application of PCR: Based on the understanding of PCR's function, the correct answer is that PCR is used to amplify a single gene or small sequence of DNA.