Translation: Protein Synthesis from mRNA (Degree Level)
Translation is the biological process where the genetic code carried by messenger RNA (mRNA) is decoded to build a specific polypeptide or protein. It occurs in the cytoplasm on ribosomes.
Key Components Involved:
| Component | Function |
|---|---|
| mRNA | Carries the codon sequence (triplets of nucleotides) specifying amino acids. |
| Ribosome | Molecular machine composed of rRNA and proteins; site of translation. |
| tRNA (transfer RNA) | Brings specific amino acids to the ribosome; has an anticodon complementary to mRNA codon. |
| Amino acids | Building blocks of proteins. |
| Initiation factors, Elongation factors, Release factors | Proteins that assist the translation stages. |
Steps of Translation:
1. Initiation
- Small ribosomal subunit binds the mRNA near the start codon (AUG).
- Initiator tRNA carrying methionine (anticodon UAC) binds start codon.
- Large ribosomal subunit attaches forming the complete ribosome.
2. Elongation
- Next tRNA with complementary anticodon enters A site.
- Peptide bond forms between amino acids at P and A sites.
- Ribosome moves along mRNA (translocation), shifting tRNAs from A to P site, P to E site (exit).
- Process repeats, adding amino acids to growing polypeptide.
3. Termination
- When ribosome reaches a stop codon (UAA, UAG, UGA), release factors bind.
- Polypeptide chain is released.
- Ribosome subunits disassemble.
Interactive Model: Visualizing Translation
This model shows the mRNA strand, ribosome, tRNA anticodons, and amino acid chain elongating step-by-step.
Translation: Protein Synthesis Model
5′ – AUG – UUU – GGC – UAC – UAA – 3′
E
P
A
Click “Start Translation” to watch the process.