Biology · Molecular Basis of Inheritance · NEET
Because it links two languages. Amino acids have no way to read the mRNA code by themselves. Francis Crick said there must be a middle molecule that reads the code on one side and holds the matching amino acid on the other side. tRNA does exactly this: its anticodon loop reads the mRNA codon, and its amino acid acceptor end carries the correct amino acid. So it 'adapts' the nucleotide code into a protein sequence. This is a very common NEET one-liner.
A codon is a group of 3 bases on the mRNA. An anticodon is a group of 3 bases on the tRNA anticodon loop. The anticodon is complementary to the codon, so it pairs with it during translation. Example: if the mRNA codon is AUG, the tRNA anticodon is UAC. Do not mix them up in the exam: codon is on mRNA, anticodon is on tRNA.
Yes, tRNA does both, and that is exactly why it is the adapter. NCERT says clearly: 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 amino acids. NEET loves to test that ONE molecule performs both roles. mRNA only provides the template; tRNA reads AND carries.
No. NCERT states directly: there are no tRNAs for stop codons. Stop codons (UAA, UAG, UGA) are read by release factors, not by tRNA. This is a favourite trap line, so remember: no tRNA and no anticodon for stop codons.
Charging (also called aminoacylation of tRNA) is the first phase of translation. The amino acid is activated using ATP energy and then linked to its own (cognate) tRNA. A tRNA carrying its amino acid is called a charged tRNA. When two charged tRNAs come close on the ribosome, a peptide bond forms between their amino acids. NEET 2020 asked this directly as the first phase of translation.
Initiator tRNA is a special tRNA used only to START translation. It reads the start codon AUG. NCERT says: for initiation, there is another specific tRNA referred to as initiator tRNA. tRNAs are specific for each amino acid, so each amino acid has its own tRNA, and initiation has its own dedicated one.
The first phase of translation is:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
One end is the anticodon loop, which reads the mRNA codon by complementary base pairing. The other end is the amino acid acceptor end, which binds the specific amino acid. These two ends together make tRNA an adapter molecule.
Francis Crick. He reasoned that amino acids cannot read the genetic code on their own, so an adapter molecule must exist to read the code on one side and bind the amino acid on the other. This molecule turned out to be tRNA.
It was called sRNA, meaning soluble RNA. It was actually known before the genetic code was worked out, but its adapter role was assigned later.
Yes. tRNAs are specific for each amino acid. There is a dedicated tRNA that carries a particular amino acid, and there is also a special initiator tRNA for starting translation.
Yes. tRNA interacts with mRNA through its anticodon, which base pairs with the mRNA codon. NEET 2025 tested a statement claiming tRNA and rRNA do NOT interact with mRNA, which is incorrect for tRNA because the anticodon reads the codon.
