translation - protein synthesis Flashcards
(23 cards)
what is translation
the stage where polypeptide chain is created using mRNA and the tRNA
where does translation happen
it happens the cytoplasm
what is the first stage of transcription
once the modified mRNA leaves the nucleus it attaches to a ribosome in cytoplasm
where on the ribosome does the mRNA attach
it attaches to the ribosome at the start codon
what is the start codon
its the first DNA or mRNA bases at the start of a sequence
describe the structure of the tRNA
each tRNA molecule has an anticodon which is at he bottom of the molecule and has an amino acid attachment site at the top of the molecule
what happen after the mRNA attaches to the ribosome at the start codon
Each tRNA molecules will bring a specific amino acid determined by an anticodon so therefore it will be the anticodon of mRNA
where are tRNA molecules found
floating around in the cytoplasm
what happens once a tRNA molecule brings the anticodon of mRNA
the tRNA molecule with the complementary anticodon to the start codon will align opposite mRNA which is held in place by the ribosome
what is the role of the ribosome in transcription
to hold mRNA and tRNA in place
what happens once the anticodon to the Start codon aligns opposite mRNA
the ribosome will the move along and the mRNA codon that matches to a different complementary tRNA anticodon will then align and attach to the next codon on the mRNA
how many tRNA molecules can a ribosome hold at a time
it can hold around 2 tRNA molecules at a time
what happens once the ribosome moves along to attach to the next codon on the mRNA
then the 2 amino acids that are at the top of the tRNA molecule join together by a peptide bond this is catalysed by an enzyme and requires ATP
what bond joins the 2 amino acids at the top of the tRNA molecule
peptide bond
what is needed to create the peptide bond
there needs to be an enzyme and atp
why does protein synthesis require energy
as to make a peptide bond between amino acids you need ATP
what happens once amino acids start joining by peptide bonds
the process will continue so the next tRNA molecule with a complementary anti codon to the codon on mRNA will a; agin and the previous tRNA will detach so it can reused
when does this process end
it will happen over and over again until the ribosome reaches the stop codon at the end of the mRNA molecule
what is a stop codon
its the last 3 bases on the mRNA and it doesn’t code for an amino acid
what does a stop codon cause the ribosome to do as it doesn’t code for an amino acid
as it doesn’t code for an amino acid there isn’t a corresponding anticodon on a tRNA molecule so it cause the ribosome to death from the mRNA which is what ends translation
what are you left with at the end of translation after the anticodon has stopped the process
you’re left with a polypeptide with a primary structure of a protein so it has to be modified in the golf body for folding modification to make the final finished product
where does the polypeptide go after translation stops
to the Golgi body for folding modifications to make the final 3D shape of the finished product
