Question

ASSERTION: DNA is more stable while RNA is more reactive.
REASON: DNA was first discovered by Watson and Crick (1953).
A. Both assertion and reason are correct and the reason is the correct explanation for assertion
B. Both assertion and reason are correct but the reason is not the correct explanation for assertion
C. The assertion is correct but the reason is incorrect
D. Both assertion and reason are incorrect

Answer 1

Hint: DNA is the abbreviation for Deoxy-ribose nucleic acid whereas, RNA is the abbreviation for Ribonucleic acid. Both DNA and RNA are genetic material. However, DNA is the preferred genetic material over the RNA. Also, DNA was first identified in 1869 and it was named Nuclein.

Complete step by step answer: Assertion: DNA is more stable while RNA is more reactive.
This statement is correct. DNA is the preferred genetic material because it is more stable and it does not change during the various phases of the life cycle of any organism. On the other hand, RNA is more reactive and unstable as compared to DNA. Due to this reason, the RNA mutates at a very faster rate. This causes the viruses with the RNA genome to directly code for the synthesis of proteins and easily express the characters. Therefore, this statement is absolutely correct.
Reason: DNA was first discovered by Watson and Crick (1953).
This statement is incorrect. The DNA was first identified and discovered by Friedrich Miescher in 1869. He found it as a substance present in the nucleus and named it Nuclein. Later on, Altmann found the acidic nature of these substances and named them Nucleic acids.
On the other hand, James Watson and Francis Crick proposed the double helix model of the DNA. Their proposition was based on the observations of Erwin Chargaff. They also proposed a scheme for DNA replication. Therefore, this statement is incorrect.
Thus, based on the above observations we can conclude that the Assertion is correct but the Reason is incorrect.
Hence, the correct answer is option (C).

Note: DNA is more stable and RNA is more reactive due to the following reasons –
1. The RNA has a free 2’ hydroxyl group which makes it more labile and easily degradable. DNA does not have any such free groups present due to which it is more stable.
2. DNA has thymine (5’-Methyl uracil) in place of uracil which provides it the additional stability.