#4: Protein Synthesis -Translation Flashcards
Translation
the process of producing protein from a strand of mRNA
occurs at ribosomes
Triplet Code
when a strand of messenger RNA is translated into a polypeptide, every three bases will correspond to one amino acid
AUG means START
UAA, UAG, and UGA mean STOP
Codon
group of 3 base pairs that code for individual amino acids
Three major molecules involved in the process
mRNA
messenger RNA
binds to ribosomes
Three major molecules involved in the process
Ribosomes
consist of two subunits: a large subunit and a small subunit
have three sites used in the process of translation: A site (acceptor), P site (peptide), E site (exit)
Three major molecules involved in the process
tRNA
a single stranded RNA molecule that is folded upon itself
have two major components: anticodon (binds to mRNA), terminal arm (carries the corresponding amino acid)
Stage 1 – Initiation
the small ribosomal subunit binds to the 5’ cap on a strand of mRNA
the small ribosomal subunit moves down the strand in a 5’ to 3’ direction
once a start codon reaches the P site, the large ribosomal subunit binds and translation begins
Stage 2 – Elongation
the next tRNA molecule will enter at the A site
a peptide bond will form between the amino acids and the polypeptide chain will transfer to the tRNA molecule in the A site
the ribosome moves down the strand of mRNA and the molecules of tRNA move into the E and P sites
the molecule of tRNA in the E site will leave
the next molecule of tRNA will enter at the A site
the process repeats until the strand of mRNA has been translated and the protein molecule is complete
Stage 3 – Termination
when the ribosome reaches a stop codon, an enzyme (the release factor) dismantles the complex and translation ends
The order of the amino acids dictates…
the ultimate structure and function of the protein
