Learning Goal - Protein Synthesis - Roles of mRNA, ribosomes and tRNA in translation
3 important questions on Learning Goal - Protein Synthesis - Roles of mRNA, ribosomes and tRNA in translation
Outline the roles of mRNA, tRNA & ribosomes in translation.
The messenger RNA's base sequence is a code that the cell uses to convert the DNA information into polypeptide formation in the ribosome, with the help of the transfer RNA. The transfer RNA helps to deliver appropriate polypeptides to the ribosomes, in accordance to the base sequence in the mRNA, and the ribosomes provide a site for the specific coupling of tRNA anticodons with mRNA codons for protein synthesis.
Describe the structures of the ribosomes, including the large and small subunits, and the names and roles of the tRNA binding sites.
Ribsomes are made up of proteins and ribsomal RNA (rRNA), and contain a small and large subunit. The small subunit includes a mRNA binding site and the large subunits include 3 main tRNA binding sites (the A-site, where the tRNA enters, the P-site, where the tRNA attached to the growing polypeptide strand is, and the E-site, where the tRNA, once detached from the growing polypeptide strand, exits). There is also a site that contributes to the peptide bond formation between 2 amino acids.
Describe how an amino acid binds to a tRNA molecule.
Each tRNA molecule shape is specific, according to its anticodon base sequence. There is a dedicated enzyme to each tRNA molecule and respective amino acid. Process:
1) Amino acid, attached to ATP, binds to dedicated enzyme
2) ATP become AMP, Amino Acid-AMP complex in enzyme recruits a specific tRNA molecule
3) AMP detaches as amino acid binds with tRNA molecule, and becomes a charged tRNA molecule as a whole.
1) Amino acid, attached to ATP, binds to dedicated enzyme
2) ATP become AMP, Amino Acid-AMP complex in enzyme recruits a specific tRNA molecule
3) AMP detaches as amino acid binds with tRNA molecule, and becomes a charged tRNA molecule as a whole.
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