Question

DNA polymerase of Thermus aquaticus is:

• A. Thermolabile
• B. Thermophobic
• C. Exonuclease
• D. Thermostable

Hint:

 Thermostable enzymes are vital for high-temperature biological processes.

Answer 1

The Correct Option is D

The DNA polymerase from Thermus aquaticus, a bacterium found in hot springs, is known for its unique properties that make it invaluable in PCR (Polymerase Chain Reaction).

(A) Thermolabile - Incorrect: Thermolabile enzymes degrade at high temperatures, whereas T. aquaticus polymerase is heat-resistant.

(B) Thermophobic - Incorrect: This term describes organisms or molecules that avoid heat, which is the opposite of this enzyme's nature.

(C) Exonuclease - Partially correct but not the best answer: While some DNA polymerases have exonuclease activity, this doesn't describe the key feature of T. aquaticus polymerase.

(D) Thermostable - Correct: The DNA polymerase from T. aquaticus (Taq polymerase) is heat-stable and can withstand the high temperatures required for PCR.

The correct answer is (D) Thermostable, as this is the defining characteristic that makes Taq polymerase essential for PCR technology.

Answer 2

Thermus aquaticus is a thermophilic bacterium found in hot springs. Its DNA polymerase, known as Taq polymerase , is highly resistant to heat. This property makes it ideal for use in Polymerase Chain Reaction (PCR) , a technique that involves repeated cycles of heating (to denature DNA) and cooling (to anneal primers).

• (A): Incorrect because thermolabile means sensitive to heat, which Taq polymerase is not.
• (B): Incorrect because thermophobic means avoiding heat, which does not apply here.
• (C): Incorrect because exonuclease refers to enzymes that degrade nucleic acids from the ends, not the primary function of Taq polymerase.
• (D): Correct because thermostable accurately describes Taq polymerase's heat resistance.