B7.3 Nucleic Acids AHL 0.0 / 5 ? BiologyMolecular BiologyInternational BaccalaureateOther Created by: Lotto65Created on: 06-02-17 17:44 What happens when the mRNA comes into contact with the ribosome? The small sub unit of the ribosome binds to the mRNA with the start codon in a specific position on the mRNA binding site on the small sub unit 1 of 18 How is the mRNA positioned? So the tRNA is in the P binding site and the A and E binding sites are empty 2 of 18 What is the tRNA anticodon of the mRNA start codon? UAG 3 of 18 What is the name of the amino acid corresponding to the start codon on mRNA? Methionine 4 of 18 What is the name of the tRNA molecule that starts the polypeptide chain? Initiator tRNA 5 of 18 What binds together inside the ribosome after tRNA binds? The large and small sub unit bind together 6 of 18 What happens after the large and small sub units have bound together? A tRNA complementary to the codon adjacent to the start codon binds to binding site A 7 of 18 What is the name of the bond formed between the amino acids held by tRNAs in binding sites P and A? Peptide bond 8 of 18 What do we mean by 'elongation of polypeptides'? Adding amino acids to elongate the polypeptide chain 9 of 18 What end does the ribosome move towards in translation? 3' 10 of 18 What happens to the tRNA molecules in the binding sites when the ribosome moves along 3 bases? The tRNA in the P site moves to the E site. The tRNA in the A site that carries the polypeptide moves to the P site and the A site is vacant 11 of 18 What happens to the tRNA that is then in the E site? It detaches and moves away so the E site then becomes vacant too 12 of 18 Which site will another tRNA molecule attach to? A site 13 of 18 Do stop codons exist? Yes 14 of 18 What general direction does a ribosome move in in translation? 5' to 3' 15 of 18 Is there a complementary anticodon for the stop codon? No 16 of 18 What causes the polypeptide chain to be released from site P? Release factors attach to site A which causes the polypeptide to be released from site P 17 of 18 What happens at the very end of translation? The tRNA in site P detaches, the mRNA detaches from the small sub unit, the large and small sub units separate 18 of 18
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