Concepts and formula to Remember
Protein Synthesis:
- Aminoacyl-tRNA synthetases enzymes charge tRNA molecules with amino acids for translation.
- Codons are three-nucleotide sequences in mRNA that code for amino acids.
- The initiation codon (AUG) marks the start of protein synthesis.
- Stop codons (UAA, UAG, UGA) signal the end of translation.
- Ribosomes facilitate tRNA-mRNA pairing and protein synthesis.
Initiation of Protein Synthesis:
- Bacterial ribosomes consist of small (30S) and large (50S) subunits.
- Eukaryotic ribosomes are larger, with small (40S) and large (60S) subunits.
- Initiation factors help assemble ribosomal subunits.
- Steps in prokaryotic initiation: mRNA binding, initiator tRNA binding (AUG).
- Steps in eukaryotic initiation: mRNA binding, small ribosomal subunit assembly.
Elongation of Protein Chain:
- Elongation has three phases: codon recognition, peptide bond formation, translocation.
- Charged tRNA enters the A site guided by mRNA codon.
Termination of Protein Synthesis:
- Termination occurs at stop codons.
- Release factors recognize stop codons, leading to protein release.
Deconstruction of Ribosomal Complex:
- After termination, the ribosomal complex disassembles, releasing mRNA and tRNA.
