Which of the four treatments was the control for the experiment?
answer
the wild type mouse
question
The hypothesis was that all three segments of the regulatory region are required for highest expression of the Hoxd13 gene. Is this hypothesis supported by the results?
answer
Yes; when any of the segments were deleted, the expression level dropped to less than 100% of the control.
question
What was the effect on the amount of Hoxd13 mRNA when segments B and C were both deleted?
answer
Only about 35% of the control amount of Hoxd13 mRNA was produced.
question
Look at the blue stain in the in situ hybridization for the transgenic mouse lacking segments B and C. How would you describe the spatial pattern of gene expression in the embryo paw as compared to the control?
answer
The blue stain is generally lighter than in the control, but all four digit zones are still visible.
question
What was the effect on the amount of Hoxd13 mRNA when just segment C was deleted?
answer
Only about 60% of the control amount of Hoxd13 mRNA was produced.
question
How would you describe the spatial pattern of gene expression in the embryo paw lacking segment C as compared to the control and to the paw lacking segments B and C?
answer
The digit zones are not visibly stained as they are in the control and the paw lacking B and C.
question
Suppose the researchers had only measured the amount of Hoxd13 mRNA and not done the in situ hybridizations. What important information about the role of the regulatory segments would have been missed?
answer
The spatial patterns of Hoxd13 gene expression in the paws would have been missed.
question
Suppose the researchers had only done the in situ hybridizations and not measured the amount of Hoxd13 mRNA. What important information would have been missed?
answer
Quantitative data about Hoxd13 mRNA levels would have been missed.
question
Which of the following statements best defines the term operon?
answer
An operon is a region of DNA that codes for a series of functionally related genes under the control of the same promoter.
question
What molecule binds to promoters in bacteria and transcribes the coding regions of the genes?
answer
RNA polymerase
question
What is allosteric regulation?
answer
In allosteric regulation, a small molecule binds to a large protein and causes it to change its shape and activity.
question
Under which conditions are the lac structural genes expressed most efficiently?
answer
no glucose, high lactose
question
What happens to the expression of the lacI gene if lactose is not available in the cell?
answer
There is no change—the lacI gene is constitutively expressed.
question
What is the function of the lacZ gene?
answer
This gene encodes an enzyme, b-galactosidase, which cleaves lactose into glucose and galactose.
question
Which of the following enzymes converts ATP to cAMP?
answer
Adenylyl cyclase
question
True or false? The mechanism by which glucose inhibits expression of the lac structural genes is known as catabolite stimulation, whereas the mechanism by which lactose stimulates expression of the lac structural genes is known as allosteric regulation.
answer
false
question
The operon model of the regulation of gene expression in bacteria was proposed by _____.
answer
jacob and monod
question
Which of these is NOT a component of the lac operon?
answer
regulatory gene only
question
Regulatory proteins bind to _____.
answer
operator
question
In the presence of a regulatory protein the lac operon is _____.
answer
not transcribed
question
Which of these is a regulatory gene?
answer
D
question
Enzyme complexes that break down protein are called _____.
answer
proteasomes
question
The nuclear membrane's role in the regulation of gene expression involves _____.
answer
regulating the transport of mRNA to the cytoplasm
question
What is the function of a spliceosome?
answer
RNA processing
question
Protein-phosphorylating enzymes' role in the regulation of gene expression involves _____.
answer
protein activation
question
Use the accompanying diagram of the key developmental events in the life cycle of the fruit fly Drosophila to select the statement that best describes the timing and coordination of events necessary for normal fruit fly development.
answer
Cytoplasmic determinants localized in the unfertilized egg provide positional information for placement of the anterior-posterior axis in the embryo.
question
Which of the following is not a body segment of the fruit fly embryo?
answer
Antenna
question
Which of the following statements about a gene that shows maternal effect inheritance is true?
answer
Offspring will show a mutant phenotype if the mother has a mutant genotype.
question
True or False? Pattern formation refers to events that organize embryonic cells in space
answer
true
question
Where is bicoid mRNA translated?
answer
Fertilized egg
question
Which body part develops in regions with a low concentration of Bicoid protein?
answer
Abdomen
question
Which of the following statements about the Bicoid protein is true?
answer
The Bicoid protein is a regulatory transcription factor
question
If bicoid mRNA is injected at the anterior end of an egg from a bicoid mutant mother, what would the phenotype of the resulting larva be?
answer
The larva would be normal with one head at the anterior pole.
question
A high concentration of bicoid protein at the opposite ends of a developing Drosophila embryo would result in the development of a _____.
answer
two-headed fly
question
The bicoid gene product is directly responsible for _____ in a developing Drosophila embryo.
answer
the establishment of the anterior-posterior axis
question
The region of a Drosophila embryo with the highest concentration of bicoid protein will develop into the _____.
answer
head
question
What triggers the translation of bicoid mRNA?
answer
fertilization of the egg
question
The bicoid gene is a type of _____ gene.
answer
egg-polarity
question
The region of a Drosophila embryo with a low concentration of bicoid protein will develop into the _____
answer
abdomen
question
What process produces the gradient of bicoid protein in a fertilized egg?
answer
diffusion
question
Bicoid mRNA is translated in _____.
answer
fertilized egg
question
Which of these regions is most likely to develop into the Drosophilia's head?
answer
a
question
The bicoid gene is transcribed by _____.
answer
nurse cells
question
Select an observation that best describes a correct aspect of the two processes of restriction digest and gel electrophoresis:
answer
When separated on a gel, the pattern of DNA bands will be characteristic of those cut with Hind III, different restriction enzymes will not produce these same fragments.
question
To culture the bacteria and obtain the protein product, the bacteria must grow. Select the appropriate condition to determine if the plasmid has entered the E-coli bacterial cell.
answer
Nutrient broth to which ampicillin has been added
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