Translation and Proteins Flashcards
What is translation
Turning amino acids to polypeptides
what does trna do and what is its structure
serves as adaptor molecules to turn triplet codons in mrna to correct amino acid
contains posttranscriptionally modified bases, cloverleaf structure, contains anticodon that pairs with mrna codon, CCA sequence at 3’ end binds amino acid
what do ribosomes do
consists of large and small subunit, involved in catalyzing translation
What is required in translation
aminoacyl trna synthetase to activate trna with right appropriate amino acid
How does prokaryotic translation initiate?
shine dalgarno sequence upstream of aug base pairs with small subunit, FMETrna bind to aug in P site to set reading frame, large subunit of ribosome bind to start elongation
Describe prokaryotic elongation
charged trnas enter A site, bond between amino acid on trna at A site and growing peptired bound to trna at P site formed by peptidyl transferase, uncharged trna moves to E site and trna bound to peptide chain moves to P site
How does termination happen
signaled by stop codon in A site, polypeptide chain cleaved from trna by GTP dependent release factors
Describe eukaryotic translation
Kozak sequence identified within aug sequence by ribosome, more factors required for initiation than prokaryotes, ribosomes associated with ER
What is the one gene one enzyme hypothesis?
Proposed by beadle and tatum,One gene codes for an enzyme and mutating it blocks formation of enzyme, later changed to one gene one polypeptide chain
What is colinearity?
order of nucleotides = order of amino acids in polypeptide
what is the structure of an amino acid?
carboxyl group, amino group, R group, central carbon
What are the levels of protein structure?
primary- amino acid sequence,
secondary- alpha helix, beta sheets
tertiary- 3d conformation
quaternary - interactions between multiple polypeptide chains
forms after translation
What do enzymes do?
They are involved in biological catalysis
what are protein domains?
Fold independently of rest of the protein and have different functions, exons can encode protein domains and exon shuffling could be an evolutationary mechanism to form unique genes in eukaryotes
