TRNA

Definition

tRNA, or transfer RNA, is a type of RNA molecule that plays a critical role in translating the genetic code from mRNA into proteins. Each tRNA molecule carries a specific amino acid and has an anticodon region that pairs with the corresponding codon on the mRNA strand during protein synthesis. This ensures that the correct amino acids are added in the right sequence to form a polypeptide chain.

5 Must Know Facts For Your Next Test

1. tRNA molecules have a cloverleaf structure that allows them to effectively interact with mRNA and ribosomes during translation.
2. Each tRNA is linked to its corresponding amino acid through an enzyme called aminoacyl-tRNA synthetase, which ensures accuracy in protein synthesis.
3. There are at least 20 different types of tRNA, each specific to one of the 20 standard amino acids used in protein synthesis.
4. The process of tRNA charging occurs before translation begins, where each tRNA is attached to its respective amino acid.
5. During translation, tRNA molecules enter the ribosome at the A site, deliver their amino acids, and then exit from the E site after their anticodon has paired with the mRNA codon.

Review Questions

• How does tRNA contribute to the accuracy of protein synthesis?
  • tRNA contributes to the accuracy of protein synthesis through its ability to specifically recognize and bind to its corresponding codon on the mRNA strand. Each tRNA molecule is charged with a particular amino acid by an enzyme called aminoacyl-tRNA synthetase, which ensures that only the correct amino acid is delivered for incorporation into the growing polypeptide chain. This pairing mechanism between tRNA and mRNA codons is vital for maintaining fidelity during translation.
• Discuss the structural features of tRNA and how they facilitate its function in translation.
  • tRNA has a distinctive cloverleaf structure that allows it to fold into an L-shaped three-dimensional shape. This structure provides specific sites for binding to both amino acids and mRNA. The anticodon loop of tRNA contains a sequence that pairs with complementary codons on mRNA, while the opposite end holds the attached amino acid. This design enables tRNA to effectively deliver its amino acid to the ribosome during protein synthesis.
• Evaluate the importance of tRNA in cellular function and how disruptions in its activity could affect protein synthesis.
  • tRNA is essential for proper cellular function because it directly influences protein synthesis, which is vital for numerous cellular processes including metabolism, signaling, and structural integrity. If there are disruptions in tRNA activity—such as mutations affecting its structure or issues with charging—this can lead to incorrect or incomplete proteins being synthesized. Such errors can result in malfunctioning proteins, potentially leading to various diseases or metabolic disorders. The accuracy of tRNA pairing with mRNA codons is crucial for ensuring that proteins are made correctly according to genetic instructions.

Related terms

mRNA:

Messenger RNA, or mRNA, is the type of RNA that carries genetic information from DNA to the ribosome, where proteins are synthesized.

Ribosome:

A ribosome is a complex molecular machine made of ribosomal RNA and proteins that facilitates the assembly of amino acids into polypeptides during translation.

Amino Acid: Amino acids are organic compounds that serve as the building blocks of proteins, each encoded by specific codons in the genetic code.