Chapter 15 Flashcards
enzymes as a result of translation
mutations in genes can lead to nonfunctional enzymes
auxotrophic mutants
cannot synthesize a particular amino acid because and enzyme in the biosynthesis pathway os broke by a mutation
1. give auxotrophic mutants a compound that comes after the broken enzyme in the pathway and the mutant will live
2. give auxotrophic mutants a compound that comes before the broken enzyme in the pathway and the mutant will not live
what makes up an amino acid?
amino group, hydrogen, carboxyl group, and R group- side chain
the radical group gives each amino acid unique chemical properties- non polar allopathic, aromatic, positive or negative charge, etc.
what bonds join amino acids?
peptide bonds
primary protein structure
sequence of amino acids
determined by codons
synonymous
codons that specify the same amino acid
start codon is for ______
methionine
secondary protein structure
folds and twists due to amino acid interactions
tertiary protein structure
further folding due to secondary structure interactions
quaternary protein structure
association among multiple polypeptides
protein domains
self-stabilizing and independently functioning region of polypeptide chain; often has distinct function
process of translation
- tRNA charging
- initiation (differences between bacteria and eukaryotes)
- elongation
- termination
tRNA charging
- tRNA joins with correct amino acid due to aminoacyl tRNA synthetase
- requires ATP
initiation (bacteria)
- ribosome separates into small and large subunits
- small subunit binds to Shine-Dalgrano sequence upstream of stop codon
- initiation factors do something
- GTP is hydrolyzed
- large subunit joins to complete the ribosome
initiation (eukaryotes)
- initiation complex recognizes 5’ cap and binds there
- Kozak sequence indicates start codon
- mRNA is exported to cytoplasm
- unmodified methionine is first amino acid