what does tRNA bring to the ribosome and how does it know where to deliver these

tRNA, or transfer RNA, plays a crucial role in protein synthesis by bringing amino acids to the ribosome, where proteins are assembled. Each tRNA molecule is specific to a particular amino acid and has an anticodon—a set of three nucleotides that can base-pair with a corresponding codon on the mRNA strand being translated.

### How tRNA Knows Where to Deliver Amino Acids:

1. **Codon-Anticodon Matching**:
- The ribosome reads the mRNA sequence in sets of three nucleotides called codons. Each codon specifies a particular amino acid.
- The tRNA molecules have an anticodon that is complementary to the mRNA codon, allowing them to "match" and correctly identify where to deliver their specific amino acid.

2. **Aminoacyl-tRNA Synthetases**:
- Each amino acid is attached to its corresponding tRNA by a specific enzyme known as aminoacyl-tRNA synthetase. This enzyme recognizes both the amino acid and the corresponding tRNA and catalyzes the formation of an ester bond between them. This ensures that each tRNA carries the correct amino acid.

3. **Ribosome Function**:
- The ribosome has distinct sites (A, P, and E sites) that facilitate the addition of amino acids during protein synthesis. When the ribosome encounters a codon on the mRNA, only the tRNA with the complementary anticodon will bind to the A site of the ribosome, enabling the correct amino acid to be added to the growing polypeptide chain.

In summary, tRNA brings specific amino acids to the ribosome based on the codon sequence of the mRNA it is paired with, ensuring accurate translation of the genetic code into proteins.