Summary
Small RNA adaptors with an anticodon that bring the correct amino acid to the ribosome.
In depth
tRNA is about 76 nucleotides long and folds into a cloverleaf, then an L shape. The anticodon pairs with the mRNA codon while the 3' end holds the amino acid. Aminoacyl-tRNA synthetases attach the right amino acid to each tRNA, which is the real step that decodes the genetic code.
There are fewer tRNA types than codons because of wobble.
The cloverleaf has four arms: the acceptor stem, D arm, anticodon arm and T arm. tRNAs carry many modified bases (such as inosine and pseudouridine) which tune structure and codon recognition. There are about 45 different tRNA species in bacteria and over 500 genes for tRNA in humans, with many being copies.
The synthetases are the true translators of the code, since they link the correct amino acid to the correct tRNA; there are about 20 of them, one for each amino acid, with editing sites to remove errors. Mutations in tRNA genes in mitochondria cause diseases such as MELAS.
Example: a charged tRNA is written tRNA-Phe-Phe, meaning the tRNA for phenylalanine carrying phenylalanine.
Frequently asked questions
What is Transfer RNA?
Small RNA adaptors with an anticodon that bring the correct amino acid to the ribosome.
Which area of biology covers Transfer RNA, and how advanced is it?
Transfer RNA is one of the 52 topics in Molecular Biology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Wobble Hypothesis, Codon, Translation.
Can you give an example of Transfer RNA?
Errors of synthetases are rare, about 1 in 10,000, thanks to proofreading.
What should I learn before Transfer RNA?
Transfer RNA is a Beginner topic, so no earlier topic is required. Other Beginner topics in Molecular Biology that pair well with it include Central Dogma, DNA Replication, Base Pairing.
What topics are related to Transfer RNA?
The closest topics to Transfer RNA are Wobble Hypothesis, Codon, Translation, Genetic Code. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Transfer RNA?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Transfer RNA. To practise the whole of Molecular Biology, use the Molecular Biology quiz.
How is Transfer RNA different from Wobble Hypothesis?
Transfer RNA: Small RNA adaptors with an anticodon that bring the correct amino acid to the ribosome. Wobble Hypothesis: Flexible pairing at the third codon position lets fewer tRNAs read all 61 sense codons. Read both side by side and note what each one explains.
How should I study Transfer RNA step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Wobble Hypothesis and explain the difference aloud. Finally, take the Molecular Biology quiz and come back to this page for any question you miss.