48. Given below are two statements: one is labelled as Assertion A and the other is labelledas Reason
R.
Assertion A: Ionizing radiation can cause damage to the DNA
Reason R: Ionizing radiation generates free radicals
In light of the above statements, choose the most appropriate answer from the options given below:
(a) A is false but R is true
(b) A is true but R is false
(c) Both A and R are true and R is the correct explanation of A
(d) Both A and R are true but R is NOT the correct explanation of A

Analysis of Ionizing Radiation and Its Effect on DNA

In this scenario, we have two statements, one labeled as Assertion A and the other as Reason R:

• Assertion A: Ionizing radiation can cause damage to the DNA.

• Reason R: Ionizing radiation generates free radicals.

Now, let’s break down the given information to determine the correct relationship between the two statements.

The Effect of Ionizing Radiation on DNA

Ionizing radiation is well-known for its ability to damage biological molecules, including DNA. This radiation includes X-rays, gamma rays, and particles like alpha and beta particles. The damage caused by ionizing radiation is primarily due to its high energy, which can break chemical bonds and create charged particles (ions).

Free Radicals and Their Role in DNA Damage

Free radicals are highly reactive molecules with unpaired electrons. When ionizing radiation passes through biological tissues, it interacts with water molecules to form free radicals, particularly hydroxyl radicals (OH•). These free radicals are capable of causing significant damage to DNA by breaking strands, modifying bases, or inducing mutations.

Evaluating the Assertion and Reason

• Assertion A: Ionizing radiation can indeed cause damage to DNA. This statement is true, as it is a well-established fact that ionizing radiation can lead to DNA strand breaks and mutations.

• Reason R: Ionizing radiation generates free radicals, which is true. As discussed, free radicals are generated when ionizing radiation interacts with water and other molecules in cells, leading to DNA damage.

Conclusion

Both statements, A and R, are true. Additionally, Reason R provides a correct explanation for Assertion A, as the damage caused by ionizing radiation is largely due to the formation of free radicals, which then attack the DNA.

Correct Answer: (c) Both A and R are true and R is the correct explanation of A