Genetics Chapter 13 – Flashcards
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Complete the following vocabulary exercise related to the process of translation of mRNA to protein by the ribosome.
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Amino acids are attached to tRNA by enzymes called aminoacyl-tRNA synthetase.
The process, performed by the ribosome, of reading mRNA and synthesizing a protein is called translation.
termination of translation happens when the ribosome hits a stop codon on the mRNA.
The RNA that has an amino acid attached to it, and that binds to the codon on the mRNA, is called a tRNA.
initiation of translation always happens at the start codon of the mRNA.
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Once elongation is underway, tRNAs involved in the process occupy a series of sites on the complexed ribosome. The occupation of sites occurs in the following order.
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A site, P site, E site
tRNAs associate with sites on the ribosome in the order listed
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When a peptide bond is formed between two amino acids, one is attached to the tRNA occupying the P site and the other _______.
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is attached to the tRna occupying the A site
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In prokaryotes, the methionine that initiates the formation of a polypeptide chain differs from subsequently added methionines in that _______.
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a formyl group is attached to the initiating methionine
This modification is not present on methionine residues added during elongation.
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Translation is directly dependent on all of the following associations except _______.
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complementary base pairing between mRNA and DNA
Transcription, not translation, is dependent on this association.
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Which of the following best describes the first step in the formation of the translation initiation complex?
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The small ribosomal subunit binds to an mRNA sequence near the 5' end of the transcript
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Which region of a tRNA molecule binds to amino acids?
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3' end
The 3? end of a tRNA molecule contains the amino acid binding site.
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Which of the following statements best describes the function of aminoacyl tRNA synthetase?
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It attaches a specific amino acid to a tRNA molecule.
Aminoacyl tRNA synthetase catalyzes the charging reaction that links a specific amino acid to a tRNA molecule.
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Each aminoacyl tRNA synthetase is specific for one amino acid and a small number of tRNAs.
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true
Each aminoacyl tRNA synthetase enzyme recognizes only one amino acid, but each enzyme can often recognize several tRNAs because there is usually more than one codon for each amino acid.
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What is colinearity?
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The correspondence between the sequence of triplets and the sequence of amino acids.
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How might the described system be used to demonstrate and support the concept of colinearity?
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The nearer to the initiation site the amber mutation occurs, the shorter the resulting polypeptide.
