Chapter 18 Mastering Biology Test Questions – Flashcards
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Part A - Operon vocabulary
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1. A(n) (operonis) a stretch of DNA consisting of an operator, a promoter, and genes for a related set of proteins, usually making up an entire metabolic pathway. 2. The (genes of an operon) is/are arranged sequentially after the promoter. 3. A(n) (promoteris) a specific nucleotide sequence inDNA that binds RNA polymerase, positioningit to start transcribing RNA at the appropriateplace. 4. A(n) (regulatory genecodes) for a protein,such as a repressor, that controls thetranscription of another gene or group ofgenes. 5. Regulatory proteins bind to the (operator) to control expression of the operon. 6. A(n) (repressoris) a protein that inhibits gene transcription.In prokaryotes, this protein binds tothe DNA in or near the promoter. 7. A(n) (inducer)is a specific small molecule that binds toa bacterial regulatory protein and changes its shape so that it cannot bind to anoperator, thus switching an operon on.
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Part B - Regulation of model operons
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-Operon is not transcribed: trp operon tryptophan present. lac operon lactose abset -operon is transcribed, but not sped up through positive control: lac operon lactose present, glucose present trp operon tryptophan abset -operon is transcribed quickly through positive control: lac operon lactose persent, glucose absent
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Part A - Modification of chromatin structure Which statements about the modification of chromatin structure in eukaryotes are true?
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-Methylation of histone tails in chromatin can promote condensation of the chromatin. -Acetylation of histone tails in chromatin allows access to DNA for transcription. -Some forms of chromatin modification can be passed on to future generations of cells. -Acetylation of histone tails is a reversible process. -DNA is not transcribed when chromatin is packaged tightly in a condensed form.
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Part B - Regulation of transcription initiation
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-Control elements C, D, and E are distal control elements for the imaginin gene. -The fantasin gene will be transcribed at a high level when activators specific for control elements A, B, and C are present in the cell. -Both the fantasin gene and the imaginin gene will be transcribed at high levels when activators specific for control elements A, B, C, D, and E are present in the cell.
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Part C - Alternative RNA splicing
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ACGI ACEI ACEGI
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_____ bind(s) to DNA enhancer regions.
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activators
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What is the event that IMMEDIATELY follows the last event of this animation?
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binding of RNA polymerase to the promoter
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Which of these indicates an enhancer region?
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A
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Which of these directly bind(s) to the promoter?
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C and D
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The operon model of the regulation of gene expression in bacteria was proposed by _____.
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Jacob and Monod
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Which of these is NOT a component of the lac operon?
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regulatory gene only
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Regulatory proteins bind to _____.
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the operator
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In the presence of a regulatory protein the lac operon is _____.
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nor transcribed
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Click on the diagram to start the animation. In this animation the blue sphere represents _____.
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lactose
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Click on the diagram to start the animation. In this animation the orange object represents _____.
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RNA polymerase
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Which of these is a regulatory gene?
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D
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A high concentration of bicoid protein at the opposite ends of a developing Drosophila embryo would result in the development of a _____.
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two-headed fly
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The bicoid gene product is directly responsible for _____ in a developing Drosophila embryo.
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the establishment of the anterior-posterior axis
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The region of a Drosophila embryo with the highest concentration of bicoid protein will develop into the _____.
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head
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What triggers the translation of bicoid mRNA?
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fertilization of the egg
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The bicoid gene is a type of _____ gene.
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egg-polarity
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The region of a Drosophila embryo with a low concentration of bicoid protein will develop into the _____.
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male flowers
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What process produces the gradient of bicoid protein in a fertilized egg?
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diffusion
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Bicoid mRNA is translated in _____.
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the fertilized egg
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Which of these regions is most likely to develop into the Drosophilia's head?
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A
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The bicoid gene is transcribed by _____.
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nurse cells
