Which one of the following statements about tRNA is incorrect?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → In its actual structure, tRNA is a compact molecule which looks like a clover-leaf.
Transfer RNA (tRNA) is the adapter molecule of translation. One end reads the codon on mRNA through its anticodon; the other end carries the matching amino acid. When drawn flat, as in the book’s figure, tRNA looks like a clover-leaf; this is its secondary structure. Its real three-dimensional shape is a compact inverted L.
Option (1) tRNA has an anticodon loop that has bases complementary to the code. — Correct statement about tRNA. The anticodon loop has bases complementary to the codon, so it can pair with the code on mRNA.
Option (2) tRNA has an amino acid acceptor end to which it binds amino acids. — Correct statement about tRNA. The amino acid acceptor end binds the amino acid. Each tRNA is specific for one amino acid.
Option (3) For initiation, there is another specific tRNA that is referred to as initiator tRNA. — Correct statement about tRNA. A separate initiator tRNA is used to start translation at the start codon.
Option (4) In its actual structure, tRNA is a compact molecule which looks like a clover-leaf. — Incorrect statement about tRNA. The clover-leaf is only the secondary structure drawn in the figure. In its actual structure, tRNA is a compact molecule that looks like an inverted L.
NCERT Extract:
tRNA– the Adapter Molecule – “… 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 (Figure 5.12). For initiation, there is another specific tRNA that is referred to as initiator tRNA. There are no tRNAs for stop codons. In figure 5.12, 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.”