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5242 Cell Metabolism 2 > Protein Synthesis > Flashcards

Flashcards in Protein Synthesis Deck (15)
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mRNA is made from what strand, but is identical to which strand?

Made from template strand, but is identical to coding strand.


WHat are codons? Read from which direction?

Triplet nucleotides that code for amino acids. Read from 5' to 3' direction.


What is the start codon? Reading frame?

AUG (Met)s. Reading frame starts at start codon and ends at stop codon.


What is monocistronic and polycistronic?

Mono: Eukaryotes only have one coding region/mRNA
Poly: Prokaryotes have multiple coding regions/mRNA


Silent, missense, nonsense, splice site, and frame-shift mutations?

1. Silent=Change in codon, no change in sequence
2. Missense=Change in codon, change in sequence
3. nonsense=change in codon,change to a stop codon
4. Splice: Alters how introns are removed
5. Insertion or deletion leading to different frame.


What does tRNA do? What are the different parts of it?

it reads the codons. Acceptor site is where amino acids links. Anticodon site is were it pairs with the codon in mRNA.


Which end of the tRNA is the amino acid attached?

3' end.


Ribosomes are made up of what? What subunits?

rRNA. 30 S and 50 S subunits


WHat are the stages of protein synthesis?

1. Activation of amino acid
2. Initiation
3. Elongation
4. Termination


What couples amino acids to their cooresponding tRNA? What does it use?

aminoacyl-tRNA synthetase. Uses ATP


What is the shine-delgarno sequence?

Purine rich sequence upstream of start codon that helps orient the tRNA.


Initiation of protein synthesis requires what?

30s and 50s ribosomal units, mRNA, fMET-tRNA, GTP, Mg+2, Initiation factors.


What are the steps of protein synthesis initiation?

1. 30s unit binds to mRNA with Initiation factors.
2. fMET-tRNA orients and binds with IFactors, GTP used.
3. 50s subunit with IFactors.


What are the steps of protein synthesis elongation? What does it require?

1. Binding of incoming aminoacyl-tRNA
2. Peptide bond formation
3. Translocation
Requires GTP, elongation factors


What happens during the termination step of protein synthesis?

Release factors hydrolyze terminal bond and releases the polypeptide, ribosome dissociates.