Question

(a) Describe the structure and function of t-RNA molecule. Why is it referred to as an adapter molecule?

(b) Explain the process of splicing of hn-RNA in a eukaryotic cell. [5]

Answer 1

(a) t-RNA has a clover leaf shape or the shape of an inverted L (as shown below). It has an anticodon loop with bases which are complementary to a specific codon. It has an amino acid acceptor end. It reads the code on one hand and binds with the specific amino acid on the other hand. Thus, it is referred to as an adapter molecule. tRNA brings amino acids and reads the genetic code during translation. [2 + 0.5]

(b) The hn-RNA (heterogeneous nuclear RNA) in eukaryotes is subjected to a process called splicing where the introns are removed and the exons are joined. Capping occurs at the 5' end and adding of adenine (poly A tail) ocuurs at 3' end as diagrammatically shown below: [2 + 0.5]