Translation Flashcards
What is translation?
The second stage of protein synthesis which actually synthesises a polypeptide strand
Where does translation take place in?
The ribosomes either in cytoplasm or bound to rough endoplasmic reticulum
How does translation start?
When the mRNA molecule from transcription attaches itself to a ribosome at its start codon (AUG) to begin
What other molecules are involved in translation?
tRNA molecules which are bound to a specific amino acid
Role of tRNA molecules
At their anticodon region which is complementary to a codon on mRNA, they will bind via complementary base pairings (carrying the amino acid)
This occurs for next codon etc
What happens when the 2 tRNA molecules (attached to amino acids) are bound by complementary base pairings at their anticodon region to codons on mRNA?
In a condensation reaction, the 2 amino acids form a peptide bond
How does the process of translation occur across the whole length of the mRNA molecule?
The first tRNA molecule leaves because it detached from its amino acid so is now empty: the second one has the amino acid chain attached to it
The ribosome then moves along the mRNA strand to next codon so second tRNA is in the first place: accommodates next tRNA molecule at the next codon
When does translation stop?
When the ribosome has moved all along the mRNA strand and finally reaches stop codon= complete polypeptide strand has been formed due to interlocking of amino acids carried by tRNA molecules
What does translation determine?
The primary structure (amino acid sequence) of a protein: 3D folding by bonded R groups determined by the sequence of amino acids determines the tertiary structure thus the protein.
Purpose of start codons
To start translation by the mRNA finding ribosome to bind to it
Purpose of stop codons
To stop translation by the polypeptide detaching from the ribosome
How does tRNA bind to a specific amino acid
ATP provides energy to bond for amino acid to amino acid binding site to form
Anti codon region in tRNA to mRNA codons
Binds by complementary base pairings
What does formation of a peptide bond require?
Energy in the form of ATP
What does ribosome moving across mRNA strand to next codon (and first tRNA molecule leaves) require?
Energy in the form of ATP
