Question 1

Riboswitches have been observed in

Accepted Answer

A) prokaryotes. 
B) eukaryotes. 
C) fungi. 
D) algae. 
E) yeast. 
A) prokaryotes. 
B) eukaryotes. 
C) fungi. 
D) algae. 
E) yeast. A

Question 2

What is the difference between trans- and cis-acting regulatory factors? Design an experiment that allows you to prove your answer to the question.

Accepted Answer

Trans-acting factors can regulate product regardless of where the gene is located within the genome.On the other hand,cis-acting factors need to be adjacent to the region being regulated in order to exert their effects.The designed experiments should support these findings.The lac operon provides excellent examples of support.

Question 3

A transcriptional regulator that decreases transcription of a gene from a vast distance is known as a(n)

Accepted Answer

A) enhancer. 
B) upstream control element. 
C) regulator. 
D) nonsense mutation. 
E) silencer. 
A) enhancer. 
B) upstream control element. 
C) regulator. 
D) nonsense mutation. 
E) silencer. E

Question 4

Regions of the genome that are inactive often have ________ of C nucleotides.

Accepted Answer

The answer of Regions of the genome that are inactive...

Question 5

A bacteria has the following lac operon genes located on the chromosome: I⁺P⁻Z⁻Y⁻A⁺.On a plasmid,this same bacterial cell has the lac genes I⁻P⁺Z⁻Y⁺A⁻.Which Lac proteins will be made? What type of protein expression (induced or constituitive)will there be for each protein that is made ?

Accepted Answer

Because LacI will be made,what

Question 6

In order to activate genes associated with sugar metabolism,the levels of cAMP are ________ in a bacterial cell.

Accepted Answer

The answer of In order to activate genes associated with...

Question 7

The lac repressor is

Accepted Answer

A) active when glucose is present. 
B) inactive when glucose is present. 
C) active when both glucose and lactose are present. 
D) induced when cAMP is present. 
E) rarely active. 
A) active when glucose is present. 
B) inactive when glucose is present. 
C) active when both glucose and lactose are present. 
D) induced when cAMP is present. 
E) rarely active.

Question 8

You are examining an enzyme associated with glycolysis.As such,you would expect

Accepted Answer

A) the protein to be a hormone. 
B) the protein to be induced by glucose. 
C) the protein to be constitutively expressed. 
D) the protein to be expressed only during development. 
E) the protein to be expressed only during mitosis. 
A) the protein to be a hormone. 
B) the protein to be induced by glucose. 
C) the protein to be constitutively expressed. 
D) the protein to be expressed only during development. 
E) the protein to be expressed only during mitosis.

Question 9

The graph below shows a growth curve of E.coli growing in a defined medium containing equal molar amounts of glucose and lactose.
 
Figure 23.1
Based on your knowledge of the regulation of the lac operon,the best explanation of these results is that

Accepted Answer

A) early on, due to the presence of lactose, the bacteria utilize the lac operon. Glucose is used later. 
B) the bacteria are utilizing both sugars simultaneously. 
C) the presence of glucose causes the formation of cAMP catabolic repressor protein (CRP)complexes, which shut down the lac operon until the glucose is used up. 
D) glucose is used first. Once glucose becomes limiting, intracellular cAMP increases, forming cAMP-CRP complexes that activate the lac operon to use lactose. 
E) none of the above 
A) early on, due to the presence of lactose, the bacteria utilize the lac operon. Glucose is used later. 
B) the bacteria are utilizing both sugars simultaneously. 
C) the presence of glucose causes the formation of cAMP catabolic repressor protein (CRP)complexes, which shut down the lac operon until the glucose is used up. 
D) glucose is used first. Once glucose becomes limiting, intracellular cAMP increases, forming cAMP-CRP complexes that activate the lac operon to use lactose. 
E) none of the above

Question 10

Which of the following is not a structural motif associated with transcriptional regulation?

Accepted Answer

A) combinatorial model 
B) helix-turn-helix 
C) zinc finger 
D) leucine zipper 
E) helix-loop-helix 
A) combinatorial model 
B) helix-turn-helix 
C) zinc finger 
D) leucine zipper 
E) helix-loop-helix

Question 11

Genes that are always "turned on" in a cell are referred to as

Accepted Answer

A) regulated genes. 
B) mutations. 
C) inducible. 
D) constitutive. 
E) catabolic. 
A) regulated genes. 
B) mutations. 
C) inducible. 
D) constitutive. 
E) catabolic.

Question 12

The expression of thousands of genes simultaneously is easily accomplished using which of the following techniques?

Accepted Answer

A) siRNAs 
B) Northern blotting 
C) microarrays 
D) Eastern blotting 
E) PAGE analysis 
A) siRNAs 
B) Northern blotting 
C) microarrays 
D) Eastern blotting 
E) PAGE analysis

Question 13

In eukaryotes,gene amplification is tolerated well when the amplified gene encodes for RNA products.However,it is rare or detrimental when the product is a protein.Why would it be advantageous for the cell to amplify the RNA-producing genes and not the protein-producing ones?

Accepted Answer

A) It allows for the manufacture of many RNA molecules when needed in the cell. 
B) Proteins are amplified from a single mRNA molecule. 
C) More RNA than protein is needed by the cell. 
D) RNAs are amplified from a single protein molecule. 
E) both choices A and B 
A) It allows for the manufacture of many RNA molecules when needed in the cell. 
B) Proteins are amplified from a single mRNA molecule. 
C) More RNA than protein is needed by the cell. 
D) RNAs are amplified from a single protein molecule. 
E) both choices A and B

Question 14

Groups of operons that are regulated by the same regulatory protein are known as ________.

Accepted Answer

The answer of Groups of operons that are regulated by...

Question 15

A lac   mutant would

Accepted Answer

A) be constitutive. 
B) no longer be induced by the presence of lactose. 
C) not have β-galatosidase activity. 
D) transport lactose into the cell effectively. 
E) metabolize lactose. 
A) be constitutive. 
B) no longer be induced by the presence of lactose. 
C) not have β-galatosidase activity. 
D) transport lactose into the cell effectively. 
E) metabolize lactose.

Question 16

Within a genome,an enhancer may be located

Accepted Answer

A) upstream of the gene enhanced. 
B) downstream of the gene enhanced. 
C) within the gene enhanced. 
D) choices A, B, and C 
E) both choices A and B 
A) upstream of the gene enhanced. 
B) downstream of the gene enhanced. 
C) within the gene enhanced. 
D) choices A, B, and C 
E) both choices A and B

Question 17

Of the enzymes associated with the metabolism of lactose with the lac operon,the one associated with transport of lactose into the cell is

Accepted Answer

A) β-galactosidase. 
B) transacetylase. 
C) galactoside permease. 
D) β-lactase. 
E) lactose translocase. 
A) β-galactosidase. 
B) transacetylase. 
C) galactoside permease. 
D) β-lactase. 
E) lactose translocase.

Question 18

Multiple operons may be controlled by ________ or ________.

Accepted Answer

The answer of Multiple operons may be controlled by ________...

Question 19

Genes that are expressed only when needed are

Accepted Answer

A)  unregulated. 
B) mutations. 
C) inducible. 
D) constitutive. 
E) anabolic. 
A)  unregulated. 
B) mutations. 
C) inducible. 
D) constitutive. 
E) anabolic.

Question 20

Sigma (σ)factors can regulate the initiation of transcription.Which of the following is not an example of σ regulation?

Accepted Answer

A) Some σ factors recognize promoters for genes whose products are necessary when the organism is under stress, such as heat shock. 
B) Some σ factors recognize genes necessary for nitrogen utilization. 
C) Bacteriophages may code for specific σ factors that bind the core RNA polymerase and result in recognition of viral promoters. 
D) There are many σ sigma factors associated with eukaryotic organisms. 
A) Some σ factors recognize promoters for genes whose products are necessary when the organism is under stress, such as heat shock. 
B) Some σ factors recognize genes necessary for nitrogen utilization. 
C) Bacteriophages may code for specific σ factors that bind the core RNA polymerase and result in recognition of viral promoters. 
D) There are many σ sigma factors associated with eukaryotic organisms.

Exam 23: The Regulation of Gene Expression

Riboswitches have been observed in

What is the difference between trans- and cis-acting regulatory factors? Design an experiment that allows you to prove your answer to the question.

A transcriptional regulator that decreases transcription of a gene from a vast distance is known as a(n)

Regions of the genome that are inactive often have ________ of C nucleotides.

In order to activate genes associated with sugar metabolism,the levels of cAMP are ________ in a bacterial cell.

The lac repressor is

You are examining an enzyme associated with glycolysis.As such,you would expect

The graph below shows a growth curve of E.coli growing in a defined medium containing equal molar amounts of glucose and lactose. Figure 23.1 Based on your knowledge of the regulation of the lac operon,the best explanation of these results is that

Which of the following is not a structural motif associated with transcriptional regulation?

Genes that are always "turned on" in a cell are referred to as

The expression of thousands of genes simultaneously is easily accomplished using which of the following techniques?

In eukaryotes,gene amplification is tolerated well when the amplified gene encodes for RNA products.However,it is rare or detrimental when the product is a protein.Why would it be advantageous for the cell to amplify the RNA-producing genes and not the protein-producing ones?

Groups of operons that are regulated by the same regulatory protein are known as ________.

A lac mutant would

Within a genome,an enhancer may be located

Of the enzymes associated with the metabolism of lactose with the lac operon,the one associated with transport of lactose into the cell is

Multiple operons may be controlled by ________ or ________.

Genes that are expressed only when needed are

Sigma (σ)factors can regulate the initiation of transcription.Which of the following is not an example of σ regulation?

A Preview of the Cell

The Chemistry of the Cell

The Macromolecules of the Cell

Cells and Organelles

Bioenergetics: the Flow of Energy in the Cell

Enzymes: the Catalysts of Life

Membranes: Their Structure, function, and Chemistry

Transport Across Membranes: Overcoming the Permeability Barrier

Chemotrophic Energy Metabolism: Glycolysis and Fermentation

Chemotrophic Energy Metabolism: Aerobic Respiration

Phototrophic Energy Metabolism: Photosynthesis

The Endomembrane System and Peroxisomes

Signal Transduction Mechanisms: Ielectrical and Synaptic Signaling in Neurons

Signal Transduction Mechanisms: Iimessengers and Receptors

Cytoskeletal Systems

Cellular Movement: Motility and Contractility

Beyond the Cell: Cell Adhesions, cell Junctions, and Extracellular Structures

The Structural Basis of Cellular Information: DNA, chromosomes, and the Nucleus

The Cell Cycle, DNA Replication, and Mitosis

Sexual Reproduction, meiosis, and Genetic Recombination

Gene Expression: Ithe Genetic Code and Transcription

Gene Expression: Iiprotein Synthesis and Sorting

Cancer Cells

Filters

Multiple operons may be controlled by or .