Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

→ From the very beginning of the proposition of code, it was clear to Francis Crick that there has to be a mechanism to read the code and also to link it to the amino acids, because amino acids have no structural specialities to read the code uniquely.
→ He postulated the presence of an adapter molecule that would on one hand read the code and on other hand would bind to specific amino acids.
→ The tRNA, then called SRNA (soluble RNA), was known before the genetic code was postualated.
→ However, its role as an adapter molecule was assigned much later.

→ tRNA has an anticodon loop that has bases complementary to the code, and it also has an amino acid acceptor end to which it binds to amino acids.
→ tRNAs are specific for each amino acid
→ For initiation, there is another specific tRNA that is referred to as initiator tRNA. There are no tRNAs for stop codons.
→ The secondary structure of tRNA has been depicted that looks like a clover-leaf.
→ In actual structure, the tRNA is a compact molecule which looks like inverted L.