Exam 3 BMS503, Homework Questions With Complete Solutions
Compared with cellular genomes, viral genomes:
A. are larger, with more base pairs.
B. are smaller, with fewer base pairs.
C. have genomes composed of RNA only.
D. also must have double-stranded DNA as their genome. Correct Answer-B. are smaller, with fewer base pairs.
Consider a mutation in which the change is from the codon UCU which encodes serine, to ACU which encodes threonine. Which type of point mutation is this?
A. nonsense mutation
B. frameshift mutation
C. silent mutation
D. missense mutation Correct Answer-D. missense mutation
A viral genome consists of
A. DNA
B. RNA
C. Both RNA and DNA
D. Either RNA or DNA Correct Answer-D. Either RNA or DNA Viruses with an RNA genome are dependent on the host polymerase to copy its chromosome
True
False Correct Answer-False
lacO is:
A. A gene coding for a protein that negatively regulates the expression of the arabinose operon.
B. A protein that negatively regulates the expression of the lactose operon.
C. A sequence of DNA in the lactose operon promoter.
D. A gene that codes for a protein that both positively and negatively regulates the expression of the arabinose operon. Correct Answer-C. A sequence of DNA in the lactose operon promoter.
Dr. Strummer is working with a laboratory strain of E. coli that has a deletion mutation in the lacO. Which of the following statements about this strain is correct:
A. This strain is lactose intolerant.
B. This strain will express the lactose operon when cultured in medium with high concentrations of glucose and lactose.
C. This strain will express the lactose operon when cultured in low glucose and expression is not dependent on the concentration of lactose in the culture medium.
D. This strain will express the lactose operon when cultured in medium with low concentrations of glucose and lactose. Correct Answer-??? C. This strain will express the lactose operon when cultured in low glucose and expression is not dependent on the concentration of lactose in the culture medium.
Quorum Sensing is:
A. the regulation of gene expression in response to the concentration of a
nutrient.
B. the regulation of gene expression through the use of alternative sigma
factors.
C. the regulation of gene expression in response to fluctuations in cell-
population density.
D. the regulation of gene expression through the use of DNA rearrangements. Correct Answer-C. the regulation of gene expression in response to fluctuations in cell-population density.
Expression of the operon below leads to an mRNA (the blue squiggle) that encodes three proteins. This mRNA is described as being:
A. dicistronic
B. monocistronic
C. polycistronic
D. multicistronic Correct Answer-C. polycistronic
In response to an external signal the response regulator of a two-
component signal transduction system:
A. phosphorylates a response regulator.
B. is phosphorylated and then interacts with the promoter of an operon.
Compared with cellular genomes, viral genomes:
A. are larger, with more base pairs.
B. are smaller, with fewer base pairs.
C. have genomes composed of RNA only.
D. also must have double-stranded DNA as their genome. Correct Answer-B. are smaller, with fewer base pairs.
Consider a mutation in which the change is from the codon UCU which encodes serine, to ACU which encodes threonine. Which type of point mutation is this?
A. nonsense mutation
B. frameshift mutation
C. silent mutation
D. missense mutation Correct Answer-D. missense mutation
A viral genome consists of
A. DNA
B. RNA
C. Both RNA and DNA
D. Either RNA or DNA Correct Answer-D. Either RNA or DNA Viruses with an RNA genome are dependent on the host polymerase to copy its chromosome
True
False Correct Answer-False
lacO is:
A. A gene coding for a protein that negatively regulates the expression of the arabinose operon.
B. A protein that negatively regulates the expression of the lactose operon.
C. A sequence of DNA in the lactose operon promoter.
D. A gene that codes for a protein that both positively and negatively regulates the expression of the arabinose operon. Correct Answer-C. A sequence of DNA in the lactose operon promoter.
Dr. Strummer is working with a laboratory strain of E. coli that has a deletion mutation in the lacO. Which of the following statements about this strain is correct:
A. This strain is lactose intolerant.
B. This strain will express the lactose operon when cultured in medium with high concentrations of glucose and lactose.
C. This strain will express the lactose operon when cultured in low glucose and expression is not dependent on the concentration of lactose in the culture medium.
D. This strain will express the lactose operon when cultured in medium with low concentrations of glucose and lactose. Correct Answer-??? C. This strain will express the lactose operon when cultured in low glucose and expression is not dependent on the concentration of lactose in the culture medium.
Quorum Sensing is:
A. the regulation of gene expression in response to the concentration of a
nutrient.
B. the regulation of gene expression through the use of alternative sigma
factors.
C. the regulation of gene expression in response to fluctuations in cell-
population density.
D. the regulation of gene expression through the use of DNA rearrangements. Correct Answer-C. the regulation of gene expression in response to fluctuations in cell-population density.
Expression of the operon below leads to an mRNA (the blue squiggle) that encodes three proteins. This mRNA is described as being:
A. dicistronic
B. monocistronic
C. polycistronic
D. multicistronic Correct Answer-C. polycistronic
In response to an external signal the response regulator of a two-
component signal transduction system:
A. phosphorylates a response regulator.
B. is phosphorylated and then interacts with the promoter of an operon.
