Which of the following enzymes is key to the automation of polymerase chain reactions (PCR)?

• A. DNA ligase
• B. Reverse transcriptase
• C. Restriction enzyme
• D. Human DNA polymerase
• E. Taq polymerase

Answer: (E)

Verified step by step guidance

1. Understand the purpose of PCR: Polymerase Chain Reaction (PCR) is a technique used to amplify small segments of DNA, generating thousands to millions of copies of a particular DNA sequence.
2. Identify the role of enzymes in PCR: Enzymes are crucial in PCR for synthesizing new DNA strands. The key enzyme must be able to withstand the high temperatures used in PCR cycles.
3. Consider the characteristics of Taq polymerase: Taq polymerase is derived from the thermophilic bacterium Thermus aquaticus, which allows it to function at high temperatures, making it ideal for PCR.
4. Compare Taq polymerase with other enzymes: DNA ligase is used for joining DNA strands, reverse transcriptase synthesizes DNA from RNA, restriction enzymes cut DNA at specific sites, and human DNA polymerase is not heat-stable like Taq polymerase.
5. Conclude why Taq polymerase is key: Taq polymerase's ability to withstand high temperatures and efficiently synthesize DNA during PCR cycles makes it the key enzyme for automation in PCR processes.