Transfer RNA (tRNA)

Definition

Transfer RNA (tRNA) is a type of RNA molecule that plays a crucial role in the process of translating the genetic code into proteins. Each tRNA carries a specific amino acid and has an anticodon that pairs with a corresponding codon on messenger RNA (mRNA) during protein synthesis, ensuring that the correct amino acids are added in the right order to form a polypeptide chain.

5 Must Know Facts For Your Next Test

1. tRNA molecules have a unique three-dimensional structure that allows them to accurately recognize and bind to their corresponding codons on the mRNA strand.
2. There are at least 20 different types of tRNA, each one specific for one of the 20 standard amino acids used in protein synthesis.
3. The pairing between the tRNA anticodon and the mRNA codon is based on complementary base pairing rules, ensuring the correct translation of genetic information.
4. Once a tRNA delivers its amino acid to the growing polypeptide chain at the ribosome, it is released and can be recharged with another amino acid by specific enzymes.
5. The process of tRNA charging, where amino acids are attached to their corresponding tRNAs, is catalyzed by enzymes called aminoacyl-tRNA synthetases.

Review Questions

• How does the structure of tRNA facilitate its role in protein synthesis?
  • The structure of tRNA is crucial for its role in protein synthesis. Each tRNA molecule has a cloverleaf shape that allows it to carry a specific amino acid at one end and an anticodon at the other end. This unique structure enables tRNA to accurately recognize and bind to complementary codons on mRNA during translation, ensuring that the correct amino acids are added in sequence as dictated by the genetic code.
• Discuss the importance of the pairing between tRNA anticodons and mRNA codons in the context of genetic coding.
  • The pairing between tRNA anticodons and mRNA codons is fundamental for accurate genetic coding during protein synthesis. This interaction ensures that the information encoded in the mRNA is translated into a specific sequence of amino acids in a polypeptide chain. If there is any mismatch between the anticodon and codon, it could lead to incorrect amino acids being incorporated into proteins, potentially resulting in nonfunctional or harmful proteins.
• Evaluate the significance of aminoacyl-tRNA synthetases in the process of translation and how they contribute to protein fidelity.
  • Aminoacyl-tRNA synthetases play a vital role in maintaining the fidelity of protein translation. These enzymes are responsible for attaching the correct amino acid to its corresponding tRNA, ensuring that each tRNA molecule is 'charged' with the appropriate amino acid before entering the ribosome for translation. The accuracy of this charging process is critical; any errors can lead to misincorporation of amino acids in proteins, which may disrupt cellular functions or lead to diseases. Therefore, aminoacyl-tRNA synthetases are essential for preserving the integrity of genetic information as it is expressed through proteins.

Related terms

Amino Acid: The building blocks of proteins, amino acids are organic compounds that combine to form proteins, with each tRNA molecule carrying a specific amino acid.

Codon: A sequence of three nucleotides on mRNA that corresponds to a specific amino acid or a stop signal during protein synthesis.

Ribosome: A complex molecular machine found within all living cells that facilitates the translation of mRNA into protein by bringing together tRNA and mRNA.