Question

Which of the following is an unsual nucleoside that is found in tRNA but not mRNA?

a. Adenine
b. Inosine
c. Proline
d. Phenylalanine
e. Guanine

Answer 1

Inosine

Step-by-step explanation:

• Inosine the unusual nucleoside which is found in tRNA but not in mRNA.
• Inosine is derived from the nucleoside adenosine, adenosine is present in mRNA, however in case of tRNA, there is deamination of adenosine and thus, inosine is formed.
• The enzyme that is responsible for carrying out this reaction is called as tRNA A:34 deaminases, here the position 34 indicates that the deamination takes place at position 34 of the tRNA.
• The formation of inosine is essential for the wobble base pairing to take place.
• The formation of inosine takes place when the hypoxanthine attaches to a ribose ring with the help of the beta glycosidic bond.