Question

Assertion (A): In eukaryotes, both introns and exons are transcribed to form hnRNA.
Reason (R): Splicing is required in prokaryotes.

• A. Both assertion and reason are true and reason is the correct explanation of assertion
• B. Both assertion and reason are true but reason is not the correct explanation of assertion
• C. Assertion is true but reason is false
• D. Both assertion and reason are false

Answer 1

The correct option is C Assertion is true but reason is false

In eukaryotes, DNA transcription results in the synthesis of RNA that contains both the non- coding introns and the coding exons and is known as heterogeneous nuclear RNA (hnRNA).

In the nucleus, the hnRNA undergoes further processing. As a part of this processing, the introns are removed from the hnRNA and exons are ligated together. This process is called splicing.
An unusual nucleotide, methyl guanosine triphosphate is added to the 5’ end of the RNA by a process known as capping and a chain of adenine nucleotide is added to the 3’ end of RNA by a process known as tailing. After splicing, capping and tailing the RNA is called functional mRNA. It then exits the nucleus and enters cytoplasm.

In prokaryotes such as bacteria, the mRNA does not require any processing because they lack introns. Therefore, splicing is not required in prokaryotes.