Transfer RNA: Study with Video Lessons, Practice Problems & Examples

Transfer RNA (tRNA) plays a crucial role in translation by converting codons, sequences of three nucleotides, into specific amino acids. Each tRNA has an anticodon that is complementary to the codon, allowing for accurate pairing. The amino acid attachment site on tRNA binds the corresponding amino acid, facilitated by aminoacyl tRNA synthetases—20 distinct enzymes, one for each amino acid. A tRNA with an attached amino acid is termed "charged," essential for protein synthesis. Understanding tRNA structure and function is vital for grasping the translation process in molecular biology.

tRNA

Hi. In this video, we're going to be talking about transfer RNA. So transfer RNA, which is shorthand is tRNA, and this is responsible for translating a codon, so those 3 nucleotides, into a single amino acid. So this is the adapter, so to speak, between the codon itself and the amino acid. So the structure of a tRNA on it is, it kind of looks like a cloverleaf, some people say it's an L shape. But essentially it has two main regions that you need to know about. The first is an anticodon, and this is actually a sequence, so it's an RNA sequence, because tRNA is made up of RNA, which makes sense. So it's an RNA sequence, and this RNA sequence is complimentary to the codon in which it translates. So if the codon is ACC, then the anticodon would be what? It would be UGG, because we're working with RNA, GG. So this would be on the tRNA if it attaches the amino acid to this codon. Then on the other side of the tRNA, it has an amino acid attachment site. This is where the amino acid attaches so that it can be transferred during the translation process. Now tRNA doesn't exist with just amino acids on it. tRNA is just an RNA. There has to be an enzyme that actually adds the amino acids onto it, and so that is called an aminoacyl tRNA synthetase. And this is the enzyme that attaches amino acids onto tRNA's. Now there are 20 different aminoacyl tRNA synthetases, one for every single amino acid. So there's not one enzyme that does all of them, there's 20 of them, one for each amino acid. And when we have a tRNA that has an amino acid attached onto it, we call that tRNA charged. So a charged tRNA has an amino acid on. So this is what tRNA looks like. This is let me back up. This is why people say it looks like a cloverleaf, and this is why people say it looks like an L. And you can say whatever you want to, but this is entirely RNA. So the anticodon region is here in gray, you see it here, and so this is the anticodon. And the amino acid binding site is here, in this like goldish yellow color. So that's where the amino acid binds on to. And so understanding tRNAs and how they work is super important to understanding translation. So, with that, let's now move on.

Which of the following structures is not a part of a transfer RNA?

• A. Anticodon
• B. Amino acid attachment site
• C. Codon
• D. Clover leaf structure

Which of the following enzymes is responsible for attaching amino acids onto the tRNA?

• A. tRNA attachases
• B. Aminoacyl-tRNA synthetases
• C. Aminoacyl-tRNA attachases
• D. tRNA lysases

Here’s what students ask on this topic:

What is the role of transfer RNA (tRNA) in protein synthesis?

Transfer RNA (tRNA) plays a crucial role in protein synthesis by translating codons, sequences of three nucleotides, into specific amino acids. Each tRNA molecule has an anticodon that is complementary to a codon on the mRNA, ensuring accurate pairing. The tRNA also has an amino acid attachment site where the corresponding amino acid binds. This binding is facilitated by aminoacyl tRNA synthetases, which are specific enzymes for each of the 20 amino acids. A tRNA with an attached amino acid is termed 'charged' and is essential for the elongation of the polypeptide chain during translation.

How does the anticodon of tRNA ensure accurate translation of mRNA codons?

The anticodon of tRNA ensures accurate translation of mRNA codons through complementary base pairing. Each anticodon is a sequence of three nucleotides that is complementary to a specific mRNA codon. For example, if the mRNA codon is ACC, the anticodon on the tRNA would be UGG. This complementary pairing allows the tRNA to bring the correct amino acid to the ribosome, ensuring that the amino acids are added in the correct sequence to form a functional protein.

What is the function of aminoacyl tRNA synthetases in translation?

Aminoacyl tRNA synthetases are enzymes that play a critical role in translation by attaching the correct amino acid to its corresponding tRNA. There are 20 different aminoacyl tRNA synthetases, one for each amino acid. These enzymes recognize both the specific tRNA and its corresponding amino acid, catalyzing the formation of a covalent bond between them. This process 'charges' the tRNA, making it ready to deliver the amino acid to the ribosome during protein synthesis.

Why is a tRNA with an attached amino acid called 'charged'?

A tRNA with an attached amino acid is called 'charged' because it is ready to participate in the translation process. The term 'charged' indicates that the tRNA has been loaded with its specific amino acid by an aminoacyl tRNA synthetase. This charged tRNA can then deliver the amino acid to the ribosome, where it will be added to the growing polypeptide chain, facilitating protein synthesis.

What are the two main regions of a tRNA molecule and their functions?

The two main regions of a tRNA molecule are the anticodon and the amino acid attachment site. The anticodon is a sequence of three nucleotides that is complementary to a specific mRNA codon, ensuring accurate base pairing during translation. The amino acid attachment site is where the corresponding amino acid binds, facilitated by aminoacyl tRNA synthetases. These two regions work together to ensure that the correct amino acid is added to the growing polypeptide chain during protein synthesis.