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Flashcards in Translation Deck (17):
1

What is translation

the mechanism by which the sequence of codons in mRNA is converted into a sequence of amino acids in a polypeptide chain

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Location

Translation occurs in the cytoplasm

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aminoacyl-tRNA synthetase
3' CCA end
aminoacyl-tRNA complex

aminoacyl-tRNA synthetase catalyses the attachment of a specific amino acid to 3'CCA end of each tRNA molecule forming an aminoacyl-tRNA complex

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determined by anticodon

binding of specific amino acid to each tRNA is determined by anticodon of tRNA

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Small ribosomal subunit

Small ribosomal subunit binds to 5' end of mRNA and moves downstream in search of start codon (AUG)

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Initiator tRNA

an initiator tRNA carrying methionine binds to the start codon on mRNA

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Large ribosomal subunit
initiation complex

Large ribosomal subunit then binds to small ribosomal subunit, forming the initiation complex

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Anticodon
complementary base-pairs

Anticodon of an incoming aminoacyl-tRNA complex forms complementary base pairs with the mRNA codon in the A site of the ribosome

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Ribozyme/peptidyl transferase

Ribozyme/peptidyl transferase catalyses peptide bond formation between the amino acid carried by the tRNA in the A site with the amino acid/polypeptide bound to tRNA in the P site

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tRNA
A to P

tRNA in A site is translocated to the P site

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tRNA
P to E

tRNA in the P site moves to E site and released

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elongation
stop codon

elongation is repeated until ribosome reaches a stop codon

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Release factor

Release factor binds directly to the stop codon in the A site

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the addition of water

release factor causes the addition of a water molecule

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hydrolyses the completed polypeptide

this reaction hydrolyses the completed polypeptide from the tRNA and frees the polypeptide from the ribosome

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disassembled

Translational complex is disassembled

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3D conformation

Polypeptide chain folds into its unique 3-dimensional conformation to form protein