ScienceChemistryBiochemistryBIOL Chapter 12 Review
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BIOL Chapter 12 Review

Ulyses Phillips avatar Ulyses Phillips
25 July 2022
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question
The genetic code is degenerate. That means
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a particular amino acid can be specified by more than one codon.
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The genetic code consists of ____ codons that specify amino acids, and ____ codons that do not specify amino acids.
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61/3
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There is only one start codon, AUG. This means that
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all newly-made polypeptides have a methionine at their amino end.
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A 5'-CUA-3' codon in an mRNA could be recognized by which of the following anticodon sequences in a tRNA?
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3'-GAU-5'
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The reason that the genetic code can correctly specify the order of amino acids in a polypeptide is
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specific tRNAs become attached to specific amino acids.
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A characteristic shared by eukaryotic mRNA, tRNA, and ribosomal RNA is that...
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they are all transcribed from DNA
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Assign the correct entries in this table comparing transcription to translation.
Assign the correct entries in this table comparing transcription to translation.
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Transcription Enzyme - RNA polymerase Template - DNA Initiation - Promoter Termination - Terminator sequence Translation Enzyme - Ribozyme Template - mRNA Initiation - Start codon Termination - Stop codon
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New amino acids (other than the initial f-Met) enter at which site?
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A
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What is unusual about the initiator tRNA in prokaryotes?
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It carries a modified amino acid AND it does not bind to the ribosome at the A site
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If an aminoacyl-tRNA synthetase added the wrong amino acid to a tRNA, what would happen?
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The tRNA would carry the wrong amino acid, and it would be incorporated into the growing protein.
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The transcription enzyme first attaches to the ________ of the gene.
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promoter
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RNA polymerase is able to open the DNA double helix as it moves down the template. What type of enzymatic activity does this mean RNA polymerase must possess?
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Helicase activity
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Why are nucleotide triphosphates used to polymerize RNA?
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The triphosphate is a high energy molecule so that polymerization is spontaneous.
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The terminator of a gene is located upstream of the coding region.
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False
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Which of the following statements about eukaryotic mRNA is TRUE?
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a cap is added to their 5' end, a poly-A tail is added to their 3' end, and each usually specifies only a single protein
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Splicing joins together
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two exons.
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Which of these events occur as a prokaryotic mRNA is being transcribed?
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translation of protein
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Why do eukaryotes require a 5' cap and a poly-A tail but prokaryotes don't?
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Prokaryotes don't need to transport their RNA out of the nucleus, so they don't need these features.
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Which type of RNA is involved in protein synthesis?
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*All of these* - mRNA - tRNA - rRNA
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Where does the greatest variability among codons specifying the same amino acid occur?
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in the third nucleotide of the triplet
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How does a eukaryotic ribosome initially bind to the mRNA?
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The small subunit binds to the 5' guanine cap
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How does a cell know which sequences to remove from the pre-mRNA transcript as introns?
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Complementary sequences in the snRNP bind to the splice sites in the primary transcript.
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Which of the following statements about the segment of DNA below is TRUE? 5'-CTATGGGCCATTTTTTAACGGGAGGCCCATGAA-3' 3'-GATACCCGGTAAAAAATTGCCCTCCGGGTACTT-5'
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There are two possible transcripts that are transcribed on opposite strands of the helix.