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RNA viruses require their own supply of certain enzymes because
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Host cells lack enzymes that can replicate the viral genome
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Viral DNA makes mRNA by the process of _____.
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Transcription
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How do prions, which are misfolded proteins, infect organisms
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Prions enter brain cells and cause normal forms of the protein to refold into the prion form
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The functioning of enhancers is an example of
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The stimulation of translation by initiation factors
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MiRNAs can control gene expression by what action?
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Binding to mRNAs and degrading them or blocking their translation
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CDNA is synthesized from what molecule using an enzyme known as what?
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MRNA ... reverse transcriptase
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A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have
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T4 protein and T4 DNA
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Which of the following statements about the DNA in one of your brain cells is true?
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It is the same as the DNA in one of your heart cells
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Muscle cells differ from nerve cells mainly because they
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Express different genes
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Which of the following statements best defines the term operon?
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An operon is a region of DNA that codes for a series of functionally related genes under the control of the same promoter
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What molecule binds to promoters in bacteria and transcribes the coding regions of the genes?
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RNA polymerase
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What is allosteric regulation?
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In allosteric regulation, a small molecule binds to a large protein and causes it to change its shape and activity.
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Under which conditions are the lac structural genes expressed most efficiently?
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No glucose, high lactose
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What happens to the expression of the lacI gene if lactose is not available in the cell?
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There is no change—the lacI gene is constitutively expressed.
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What is the function of the lacZ gene?
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This gene encodes an enzyme, b-galactosidase, which cleaves lactose into glucose and galactose.
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