Cystic fibrosis is caused by mutations in the CFTR gene, which encodes for a chl
ID: 40003 • Letter: C
Question
Cystic fibrosis is caused by mutations in the CFTR gene, which encodes for a chloride channel. You are studying cystic fibrosis patients to determine what mutation they possess in the CFTR gene. The difference between the mutant and wild type CFTR genes can be uncovered by examining the CFTR:
(1 point - partial possible)
DNA
mRNA
protein
2.
You decide to identify the CFTR mutation by analyzing the genomic DNA of your patients compared to genomic DNA of healthy individuals. You specifically are looking to see whether a specific gene truncation has occurred in the patients. You will determine this using hybridization techniques. Which of the following will allow you to accomplish this?
(1 point - partial possible)
Using an RNA probe complementary to the region not removed by the truncation.
Using an RNA probe complementary to the region removed by the truncation.
Using an DNA probe complementary to the region not removed by the truncation.
Using an DNA probe complementary to the region removed by the truncation.
3.
You would like to ensure that this experiment (to determine whether patients have a specific CFTR gen truncation using hybridization) is properly controlled. Which of the following samples must you include?
(1 point - partial possible)
The genome of a healthy individual who does not have CFTR.
The genome of a CFTR patient known to have the specific truncation you are trying to identify.
The genome of a CFTR patient with a point mutation in a separate region of the gene but without the disease truncation.
The genome of a healthy individual married to a CFTR patient with the specific truncation you are trying to identify.
The genome of a patient with muscular dystrophy, which can be due to a trucation in the dystrophin gene.
4.
To conduct the hybridization experiment, you are trying to decide between using a DNA or RNA probe. Which would be a better choice and why?
(1 point)
An RNA probe because RNA has uracil bases.
An RNA probe because it could also be used in a translation experiment.
A DNA probe because it is more stable than RNA.
A DNA probe because RNA cannot bind to DNA.
5.
Which of the following will lower the Tm of a given DNA strand?
(1 point - partial possible)
Increasing the percentage of GC base pairs.
Raising the pH of the solution from extremely acidic to neutral.
Decreasing the salt concentration in the DNA solution from 50mM NaCl to 5mM NaCl.
None of the above.
6.
Imagine Hershey/Chase had used an RNA virus (genome composed of RNA) instead of a DNA virus in their experiment. Would radioactivity still have been found in the pellet?
(1 point)
A.No, because only DNA can be labeled with radioactivity.
B.No, because the RNA genome would not enter the bacteria upon infection.
C. No, because while DNA and RNA nucleotides are similar, they are not identical.
D. Yes, because DNA and RNA nucleotides are similar.
7.
Griffith and Avery's transformation experiments allowed us to identify that DNA is our genetic information. Which of the following scenarios would result in bacterial cells that are capable of killing mice upon injection?
(1 point - partial possible)
A. Heat killed non-virulent bacteria is added to a live virulent bacteria strain.
B. Heat killed virulent bacteria is added to a heat killed non-virulent bacteria strain.
C. A heat killed virulent bacteria that is treated with a nuclease, is then added to a non-virulent bacteria strain.
D.Heat killed mouse cells are added to a non-virulent bacteria.
8.
The human genome consists mostly of non-coding DNA. Which of the following are benefits of this?
(1 point - partial possible)
A. Random DNA mutations generally won't affect RNA and protein function.
B. It is faster to duplicate the genome when these are present.
C. The existence of introns can lead to multiple variations of proteins encoded by a single gene.
D. Abundant non-coding genome is a protective feature against the consequences of transposition of mobile elements.
Explanation / Answer
1. DNA, mRNA and protein
2.
Using an RNA probe complementary to the region removed by the truncation.
Using an DNA probe complementary to the region removed by the truncation.
3.
The genome of a healthy individual who does not have CFTR.
The genome of a CFTR patient known to have the specific truncation you are trying to identify.
4.A DNA probe because it is more stable than RNA.
5.Decreasing the buffer concentration from 50mM NaCl to 5mM NaCl.
6. D.Yes, because DNA and RNA nucleotides are similar
7. A.Heat killed non-virulent bacteria is added to a live virulent bacteria strain.
8.
A. Random DNA mutations generally won't affect RNA and protein function.
C. The existence of introns can lead to multiple variations of proteins encoded by a single gene.
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