1. Initiation:
- The small ribosomal subunit binds to the mRNA molecule.
- The first tRNA molecule, carrying the amino acid methionine (Met), binds to the start codon (AUG) on the mRNA.
- The large ribosomal subunit joins the complex, creating a functional ribosome.
2. Elongation:
- The ribosome moves along the mRNA, reading the codons (groups of three nucleotides) one by one.
- For each codon, a specific tRNA molecule carrying the corresponding amino acid enters the ribosome.
- The amino acid is added to the growing polypeptide chain, forming a peptide bond with the previous amino acid.
- The tRNA that delivered the amino acid detaches and exits the ribosome.
3. Termination:
- The ribosome reaches a stop codon (UAG, UAA, or UGA) on the mRNA.
- A release factor protein binds to the stop codon, causing the polypeptide chain to detach from the ribosome.
- The ribosome disassembles, and the newly synthesized protein is released.
Key Components Involved:
- mRNA (messenger RNA): Carries the genetic code from the DNA to the ribosomes.
- Ribosomes: Cellular organelles where protein synthesis occurs. They have two subunits: small and large.
- tRNA (transfer RNA): Small RNA molecules that bring specific amino acids to the ribosome, matching them to the codons on the mRNA.
- Amino acids: The building blocks of proteins.
- Release factors: Proteins that terminate translation.
Importance of Translation:
Translation is a vital process for all living organisms, as it allows cells to synthesize the proteins they need for structure, function, and regulation. These proteins include enzymes, hormones, antibodies, and many more essential components.
Note: After translation, the newly synthesized protein may undergo further processing, such as folding into its correct 3D structure, or modifications like glycosylation or phosphorylation. These modifications are crucial for the protein's function and stability.
