Question

Which isotope is commonly used for radioactive DNA labelling?

• A. \(^{12}\mathrm{C}\)
• B. \(^{32}\mathrm{P}\)
• C. \(^{14}\mathrm{N}\)
• D. \(^{16}\mathrm{O}\)

Hint:

Common radioactive isotopes in molecular biology: \[ \boxed{ \begin{aligned} ^{32}\mathrm{P} &\rightarrow \text{DNA/RNA labelling} ^{35}\mathrm{S} &\rightarrow \text{Protein labelling} ^{3}\mathrm{H} &\rightarrow \text{DNA and metabolic studies} \end{aligned} } \]

Answer 1

The Correct Option is B

Step 1: Recall radioactive DNA labelling. DNA contains phosphate groups in its backbone. Therefore, radioactive phosphorus isotopes are commonly used for DNA labelling.

Step 2: Identify the commonly used isotope. The isotope \[ \boxed{^{32}\mathrm{P}} \] is widely used because it emits high-energy \(\beta\)-particles and can be readily incorporated into DNA. Therefore, \[ \boxed{(B)} \] is the correct answer.