Translation: Ribosome (rRNA)
- Single mRNA molecule is served by many ribosomes at the same time.
- Made up of a complex of ribosomal RNA and proteins.
- 2 Separate sub-units until they are attracted to a binding site on the mRNA molecule.
- Have binding sites that attract tRNA molecules loaded with amino acids.
- Ability of a ribosome to translate the coded information in an mRNA molecule and move along it one triplet at a time.
- It allows codon-anticodon pairing to occur.
- It moves along the mRNA one triplet at a time.
- Has 3 binding sites for tRNA: E-site, P-site, A-site
tRNA and Ribosome
- tRNA in the A site is translocated to the P site, taking the mRNA along with it. Meanwhile the tRNA in the P site moves to the E site and is released from the ribosome.
- P site is occupied by the tRNA attached to the growing polypeptide chain.
- A site binds the incoming tRNA the next amino acid to be added.
- Ribosome joins with the 5’end of an mRNA molecule.
- AUG codon acts as a ‘begin here’ symbol.
- When the ribosome reaches a ‘stop’ codon, it breaks free and can then begin reading another mRNA molecule to make another protein molecule.