QBM Practice Exam 3: Chapters 13-18
Chapter 13:
1. Which DNA purification technique involves purifying the sample using an ultracentrifuge?
a. Salting-out.
b. Alkaline lysis.
c. Phenol-chloroform extraction.
d. Anion exchange chromatography.
e. Cesium chloride gradient.
2. What technique is used to increase plasmid copy number and purify plasmids?
a. Miniprep.
b. Gel extraction.
c. DNA sequencing.
d. Agarose gel electrophoresis.
e. Polymerase chain reaction.
3. The absorbance of a DNA sample at A260 = 1.0, and A280 = 1.0. Which of the following is TRUE?
a. This sample is sufficiently pure.
b. There is approximately 100 micrograms/ml of DNA in this sample.
c. There is significant protein contamination of this sample.
d. EDTA was not added to the sample.
e. There is a high amount of protein oxidation in this sample.
4. Which of the following does NOT inhibit RNase activity?
a. 3’ polyA tail.
b. Diethyl pyrocarbonate.
c. Baking at 280 °C overnight.
d. Guanidium isothiocyanate.
e. EDTA.
,5. The following DNA fragments are run on a gel. The DNA fragment in Lane 4 below is
a. 50 bp
b. 225 bp
c. 475 bp
d. 600 bp
e. 950 bp
6. Ethidium bromide is frequently chosen to visualize DNA on a gel because
a. it is the newest technology in visualizing agents.
b. it is more sensitive than Sybr Green and crystal violet.
c. it is the safest visualizing reagent based on an Ames Test.
d. All answer choices are correct.
7. To extract DNA from a gel you would perform a
a. gel extraction.
b. freeze squeeze.
c. Chomczynski and Sacchi isolation.
d. gel extraction and freeze squeeze.
e. All answer choices are correct.
, Chapter 14:
8. A collection of cells that are all descendents from the same cell are called
a. recombinants.
b. clones.
c. F+
d. conjugated.
e. transformants.
9. Which of the following is TRUE about restriction enzymes?
a. They are capable of ligating two pieces of DNA together.
b. They generally form trimers around DNA.
c. They are used during Cre-Lox recombination.
d. They generally recognize palindromic DNA.
10. Based on the restriction enzyme table below, which of the following is TRUE?
a. EcoRI and XhoI should ideally be used together in Buffer 1 or Buffer 2.
b. XbaI and BamHI should ideally be used together in Buffer 2.
c. A gel extraction must be performed before digesting DNA with HpaI if EcoRI in Buffer 1
was used.
d. XbaI and EcoRI can’t be used to digest DNA at the same time in Buffer 1.
e. BamHI and HpaI can efficiently cut DNA together in Buffer 4.
Chapter 13:
1. Which DNA purification technique involves purifying the sample using an ultracentrifuge?
a. Salting-out.
b. Alkaline lysis.
c. Phenol-chloroform extraction.
d. Anion exchange chromatography.
e. Cesium chloride gradient.
2. What technique is used to increase plasmid copy number and purify plasmids?
a. Miniprep.
b. Gel extraction.
c. DNA sequencing.
d. Agarose gel electrophoresis.
e. Polymerase chain reaction.
3. The absorbance of a DNA sample at A260 = 1.0, and A280 = 1.0. Which of the following is TRUE?
a. This sample is sufficiently pure.
b. There is approximately 100 micrograms/ml of DNA in this sample.
c. There is significant protein contamination of this sample.
d. EDTA was not added to the sample.
e. There is a high amount of protein oxidation in this sample.
4. Which of the following does NOT inhibit RNase activity?
a. 3’ polyA tail.
b. Diethyl pyrocarbonate.
c. Baking at 280 °C overnight.
d. Guanidium isothiocyanate.
e. EDTA.
,5. The following DNA fragments are run on a gel. The DNA fragment in Lane 4 below is
a. 50 bp
b. 225 bp
c. 475 bp
d. 600 bp
e. 950 bp
6. Ethidium bromide is frequently chosen to visualize DNA on a gel because
a. it is the newest technology in visualizing agents.
b. it is more sensitive than Sybr Green and crystal violet.
c. it is the safest visualizing reagent based on an Ames Test.
d. All answer choices are correct.
7. To extract DNA from a gel you would perform a
a. gel extraction.
b. freeze squeeze.
c. Chomczynski and Sacchi isolation.
d. gel extraction and freeze squeeze.
e. All answer choices are correct.
, Chapter 14:
8. A collection of cells that are all descendents from the same cell are called
a. recombinants.
b. clones.
c. F+
d. conjugated.
e. transformants.
9. Which of the following is TRUE about restriction enzymes?
a. They are capable of ligating two pieces of DNA together.
b. They generally form trimers around DNA.
c. They are used during Cre-Lox recombination.
d. They generally recognize palindromic DNA.
10. Based on the restriction enzyme table below, which of the following is TRUE?
a. EcoRI and XhoI should ideally be used together in Buffer 1 or Buffer 2.
b. XbaI and BamHI should ideally be used together in Buffer 2.
c. A gel extraction must be performed before digesting DNA with HpaI if EcoRI in Buffer 1
was used.
d. XbaI and EcoRI can’t be used to digest DNA at the same time in Buffer 1.
e. BamHI and HpaI can efficiently cut DNA together in Buffer 4.
