18

Last update by Shanal on 11/06/2013
157180 People have viewed this Quiz
  • Share

10) Transcription of the structural genes in an inducible operon

A) occurs continuously in the cell.

B) starts when the pathway's substrate is present.

C) starts when the pathway's product is present.

D) stops when the pathway's product is present.

E) does not result in the production of enzymes.

Answer:

B) starts when the pathway's substrate is present.

View 18 as Flashcard Deck

Related Quiz Content
  • boydstun 3
    Answered in 18

    11) How does active CAP induce expression of the genes of the lactose operon?

    A) It terminates production of repressor molecules.

    B) It degrades the substrate allolactose.

    C) It stimulates splicing of the encoded genes.

    D) It stimulates the binding of RNA polymerase to the promoter.

    E) It binds steroid hormones and controls translation.

    D) It stimulates the binding of RNA polymerase to the promoter.

  • boydstun 3
    Answered in 18

    12) For a repressible oPEron to be transcribed, which of the following must occur?

    A) A corepressor must be present.

    B) RNA polymerase and the active repressor must be present.

    C) RNA polymerase must bind to the promoter, and the repressor must be inactive.

    D) RNA polymerase cannot be present, and the repressor must be inactive.

    E) RNA polymerase must not occupy the promoter, and the repressor must be inactive.

    C) RNA polymerase must bind to the promoter, and the repressor must be inactive.

  • boydstun 3
    Answered in 18

    13) Allolactose induces the synthesis of the enzyme lactase. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell?

    A) The repressor protein attaches to the regulator.

    B) Allolactose binds to the repressor protein.

    C) Allolactose binds to the regulator gene.

    D) The repressor protein and allolactose bind to RNA polymerase.

    E) RNA polymerase attaches to the regulator.

    B) Allolactose binds to the repressor protein.

  • boydstun 3
    Answered in 18

    14) Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways?

    A) organizing gene expression so that genes are expressed in a given order

    B) allowing each gene to be expressed an equal number of times

    C) allowing the organism to adjust to changes in environmental conditions

    D) allowing young organisms to respond differently from more mature organisms

    E) allowing environmental changes to alter the prokaryote's genome

    C) allowing the organism to adjust to changes in environmental conditions

  • boydstun 3
    Answered in 18

    15) In response to chemical signals, prokaryotes can do which of the following?

    A) turn off translation of their mRNA

    B) alter the level of production of various enzymes

    C) increase the number and responsiveness of their ribosomes

    D) inactivate their mRNA molecules

    E) alter the sequence of amino acids in certain proteins

    B) alter the level of production of various enzymes

  • boydstun 3
    Answered in 18

    16) If she moves the promoter for the lac operon to the region between the beta galactosidase gene and the permease gene, which of the following would be likely?

    A) Three structural genes will no longer be expressed.

    B) RNA polymerase will no longer transcribe permease.

    C) The operon will no longer be inducible.

    D) Beta galactosidase will not be produced.

    E) The cell will continue to metabolize but more slowly.

    D) Beta glycolase will not be produced.

  • boydstun 3
    Answered in 18

    17) If she moves the operator to the far end of the operon (past the transacetylase gene), which of the following would likely occur when the cell is exposed to lactose?

    A) The inducer will no longer bind to the repressor.

    B) The repressor will no longer bind to the operator.

    C) The operon will never be transcribed.

    D) The structural genes will be transcribed continuously.

    E) The repressor protein will no longer be produced.

    D) The structural genes will be transcribed continuously.

  • boydstun 3
    Answered in 18

    18) If she moves the repressor gene (lac I), along with its promoter, to a position at some several thousand base pairs away from its normal position, which will you expect to occur?

    A) The repressor will no longer be made.

    B) The repressor will no longer bind to the operator.

    C) The repressor will no longer bind to the inducer.

    D) The lac operon will be expressed continuously.

    E) The lac operon will function normally.

    E) The lac operon will function normally.

  • boydstun 3
    Answered in 18

    19) If glucose is available in the environment of E. coli, the cell responds with very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect would then be a measurable effect?

    A) decreased concentration of the lac enzymes

    B) increased concentration of the trp enzymes

    C) decreased binding of the RNA polymerase to sugar metabolism-related promoters

    D) decreased concentration of alternative sugars in the cell

    E) increased concentrations of sugars such as arabinose in the cell

    E) increased concentrations of sugars such as arabinose in the cell

  • boydstun 3
    Answered in 18

    20) Muscle cells and nerve cells in one species of animal owe their differences in structure to

    A) having different genes.

    B) having different chromosomes.

    C) using different genetic codes.

    D) having different genes expressed.

    E) having unique ribosomes.

    D) having different genes expressed.

  • boydstun 3
    Answered in 18

    21) Which of the following mechanisms is (are) used to coordinately control the expression of multiple, related genes in eukaryotic cells?

    A) organization of the genes into clusters, with local chromatin structures influencing the expression of all the genes at once

    B) each of the genes sharing a common control element, allowing several activators to turn on their transcription, regardless of their location in the genome

    C) organizing the genes into large operons, allowing them to be transcribed as a single unit

    D) a single repressor able to turn off several related genes

    E) environmental signals that enter the cell and bind directly to their promoters

    A) organization of the genes into clusters, with local chromatin structures influencing the