Question

A thermostable DNA polymerase is isolated from:

• A. Thermus aquaticus
• B. Agrobacterium tumefaciens
• C. E. coli
• D. Salmonella typhimurium

Answer 1

The Correct Option is A

To identify the source of a thermostable DNA polymerase, we need to consider the unique properties of the organisms listed. Thermostable enzymes are able to function at high temperatures and are typically found in thermophilic organisms. Among the options provided:

Thermus aquaticus: This is a thermophilic bacterium that thrives in hot environments, such as hot springs. It is well-known for producing Taq polymerase, a thermostable DNA polymerase used extensively in PCR (polymerase chain reaction) techniques.

Agrobacterium tumefaciens: A bacterium known for its role in plant pathology and genetic engineering, but not for thermostability.

E. coli: A commonly used bacterium in research with a wide temperature range for growth, but its DNA polymerase is not thermostable.

Salmonella typhimurium: Another mesophilic bacterium, not associated with thermostable enzymes.

Given this information, the correct answer is Thermus aquaticus, as it produces the well-known thermostable enzyme, Taq polymerase, essential for DNA amplification at high temperatures in PCR. 

Answer 2

A thermostable DNA polymerase is an enzyme that can withstand high temperatures, making it ideal for processes that involve heat, such as the Polymerase Chain Reaction (PCR). The thermostable DNA polymerase commonly used in PCR is Taq polymerase, which is isolated from the bacterium Thermus aquaticus. This bacterium thrives in high-temperature environments, such as hot springs, which is why its DNA polymerase is particularly stable at the high temperatures used in PCR.