Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Molecular Basis of Inheritance

Question:

Read the passage given below and answer the following question.
Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are the two types of nucleic acids found in living systems. DNA acts as the genetic material in most of the organisms. RNA though it also acts as a genetic material in some viruses, mostly functions as a messenger. RNA has additional roles as well. It functions as adapter, structural, and in some cases as a catalytic molecule.The chemical structure of a polynucleotide chain (DNA or RNA). A nucleotide has three components – a nitrogenous base, a pentose sugar (ribose in case of RNA, and deoxyribose for DNA), and a phosphate group. There are two types of nitrogenous bases – Purines and Pyrimidines .

Which is a reason for less stability of RNA in comparison to DNA? (Question 4)

Options:

Presence of thymine

Presence of OH group

Presence of Ribose sugar

Presence of cytosine

Correct Answer:

Presence of OH group

Explanation:

The correct answer is option (2) -Presence of OH group

Presence of OH group

One of the reasons for the less stability of RNA in comparison to DNA is the presence of the OH (hydroxyl) group at the 2' carbon of the ribose sugar in RNA. This hydroxyl group makes RNA more susceptible to hydrolysis and degradation. DNA, on the other hand, has a hydrogen atom at the 2' position of its deoxyribose sugar, making it more stable.

The hydroxyl group in RNA can participate in reactions that lead to the breakdown of RNA molecules, making them relatively less stable compared to DNA.

So, the correct answer is: Presence of OH group.