PUZZLE: Protein Synthesis, Part 2

Once in the cytoplasm, mRNA strands attach to ribosomes, on which translation occurs. In biology, translation is the conversion of the linear message encoded on mRNA to a linear strand of amino acids to form a polypeptide, or a protein. (A peptide is two or more amino acids linked by a peptide bond).

Translation is accomplished by the interaction of mRNA, ribosomes, and transfer RNA (tRNA) which is another type of RNA molecule. tRNA is an amino acid-carrying molecule.

Translation occurs when a three-base sequence (triplet) on mRNA is read by tRNA. This triplet sequence is called a codon.

Find the tRNA that complements (will fit with) the first codon.

Within the cytoplasm, tRNA attaches to a specific free amino acid. Then the amino acid-carrying tRNA positions itself with the appropriate codon via the ribosome.

1. Move the appropriate tRNA and amino acid (alanine) into the P-site of the ribosome.
   
   Now find the t-RNA and amino acid that complements the second codon.
2. Move the appropriate tRNA and amino acid (glycine) into the T-site of the ribosome.
   
   At this point the alanine would become linked with the glycine to form a polypeptide. The alanine specific tRNA would be removed from the ribosome and the glycine specific tRNA and associated mRNA would shift from the T-site to the P-site. The next codon of the mRNA would be exposed and the appropriate tRNA and amino acid would fill in the unoccupied T-site. This process continues down the mRNA strand and upon completion a polypeptide chain, or protein, is created.
3. Click print and save the file. You will upload it with your assignment at the end of this module.