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BIO 351 EXAM 2 (Quiz_Control of Gene Expression)

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1
Which of the following molecules is a protein produced by a regulatory gene?
  • repressor
  • promoter
  • operator
  • operon
2
When taken up by a cell, which of the following molecules binds to a repressor so that the repressor no longer binds to an operator?
  • corepressor
  • inducer
  • promoter
  • CAMP
3
If a mutation deactivated a regulatory gene of a repressible operon in an E. coli cell which of the following describes the most likely outcome?
  • irreversible binding of the repressor to the operator
  • continuous translation of the mRNA because of alteration of its structure
  • complete inhibition of transcription of the structural gene controlled by that regulator
  • continuous transcription of the structural gene controlled by that regulator
4
Which of the following conditions is most likely to result in transcription of the lac operon?
  • There is more glucose in the cell than lactose.
  • The cAMP and lactose levels are both high within the cell.
  • There is glucose but no lactose in the cell.
  • The cAMP level is high and the lactose level is low.
5
For a repressible operon to be transcribed, which of the following conditions must occur?
  • RNA polymerase and active repressor must occupy the promoter.
  • RNA polymerase must bind to the promoter, and the repressor must be inactive.
  • RNA polymerase must bind to the promoter and a corepressor must be present.
  • RNA polymerase must bind the inducer, and the repressor must be inactive.
6
Under what conditions does the trp repressor block transcription of the trp operon?
  • when the repressor binds to the inducer
  • when the repressor is not bound to RNA polymerase
  • when the repressor is not bound to the operator
  • when the repressor binds to tryptophan
7
Which of the following is the most likely phenotypes of a yeast mutant that contains histones that are resistant to acetylation?
  • The mutant will require galactose for growth.
  • The mutant will show increased levels of gene expression.
  • The mutant will show decreased levels of gene expression.
  • The mutant will grow rapidly.
8
Which of the following best explains why a neuron and a pancreatic cell isolated from the same individual contain different sets of proteins?
  • Each cell type needs different proteins and, therefore, they break down proteins they don't need.
  • The set of genes in each cell type are different, therefore, they express different proteins.
  • The genes in each cell type have different promoters and, therefore, they respond to different regulatory proteins.
  • Each cell type contains different regulatory proteins and, therefore, they express different proteins.
9
DNA methylation and histone acetylation are examples of which of the following processes?
  • translocation
  • genetic mutation
  • chromosomal rearrangements
  • epigenetic phenomena
10
Which of the following statements best describes the characteristics of siRNA?
  • a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor
  • a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits
  • a double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA
  • a single-stranded RNA that can fold into cloverleaf patterns due to regions of internal complementary base pairs
11
Cytoplasmic determinants are best described as having which of the following characteristics?
  • They are maternal substances in the egg that influence the course of early development.
  • They are tissue-specific transcription factors expressed in the early embryo.
  • They are centromeric regions of DNA loosened for chromosomal replication by transcription factors.
  • They are single-stranded RNA molecules capable of binding complementary sequences and altering translation.
12
The product of the bicoid gene in Drosophila is responsible for determining which of the following embryonic features or structures during development?
  • segmentation of developing limbs
  • orientation of the anterior-posterior axis
  • orientation of the dorsal-ventral axis
  • orientation of the left-right axis
13
The functioning of enhancers is an example of _______.
  • a eukaryotic equivalent of prokaryotic promoter functioning
  • transcriptional control of gene expression
  • post-translational control that activates certain proteins
  • the stimulation of translation by initiation factors
14
Which of the following is an example of post-transcriptional control of gene expression?
  • the removal of introns and alternative splicing of exons
  • the binding of transcription factors to a promoter
  • gene amplification contributing to cancer
  • the addition of methyl groups to cytosine bases of DNA
15
Within a cell, the amount of protein made using a given mRNA molecule in that cell depends partly on _____.
  • the types of ribosomes present in the cytoplasm
  • the number of introns present in the mRNA
  • the degree of DNA methylation
  • the rate at which the mRNA is degraded
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