BIOCHEM - Protein Turnover

genetic code

the relationship between the sequence of bases in DNA and the sequence of amino acids in proteins

codon

three nucleotides that encode an amino acid

mitochondria

which part of the cell has a distinct set of tRNAs that allow for different coding than the rest of the cell?

simple hypothesis

hypothesis model that suggests that only one anticodon can recognize only one codon in tRNA codon recognition

wobble hypothesis

hypothesis model that suggests that there is flexibility in tRNA recognition due to the fact that on tRNA can recognize multiple codons

inosine

maximizes the number of codons that can be read by a particular tRNA molecule

10,000

errors in translation are one error in _____ amino acids

aminoacyl-tRNA synthetases

enzyme that activates amino acids into their active form to be attached to a tRNA

aminoacyl-AMP

the active form of amino acids that can be attached to tRNAs

aminoacyl-tRNA

an aminoacyl-AMP attached to tRNA forms _____

2

how many amino acids are consumed in the synthesis of each aminoacyl-tRNA?

aminoacyl-tRNA synthetases

what are the actual translators of the genetic code?

ribosomes

molecular machines that coordinate the interplay between aminoacyl-tRNA, mRNA, and proteins that result in protein synthesis

50S

what is the large ribosome subunit?

30S

what is the small ribosome subunit?

70S

what is the whole ribosome referred to as?

proteins and RNA

what are ribosomes made up of?

RNA

what are the catalytic sites in ribosomes completely composed of?

polyribosome

a group of ribosomes bound to an mRNA

AUG (methionine)

what is the start codon that begins the polypeptide chain?

shine-delgarno sequences

upstream nucleotides that facilitate mRNA binding and are untranslated regions (UTRs)

initiation factors

what initiate translation and start assembling the ribosome subunits to eventually get 70S?

A and E

which sites are empty when the elongation phase starts?

EF-Tu

what delivers the aminoacyl-tRNA to the A site, protects it from hydrolysis, and contributes to the accuracy of protein synthesis?

accommodation

EF-Tu induces a conformational change that places the aminoacyl-tRNA at the P and A sites to promote peptide bond formation

EF-Ts

what induces the release of GDP from EF-Tu and resets the cycle for the next aminoacyl-tRNA?

N terminus to C terminus (amino- to carboxyl-terminal)

what direction does synthesis occur?

release factors (RF)

termination of synthesis occurs via _____ that read the stop codons

secretory pathway

where proteins are translated in the endoplasmic reticulum