Buckingham - Chapter 4 - Resolution and Detection of Nucleic Acids

BrendaCamargo7

1. Which of the following molecules polymerizes to form a support medium through which nucleic acids move?

A. Ethidium bromide

B. Ethylenediaminetetraacetic acid

C. Sodium dodecyl sulfate

D. Polyacrylamide

D. Polyacrylamide

2. The positive pole in electrophoresis is indicated by which color?

A. Red

B. Black

C. Green

D. White

A. Red

3. Nucleic acids migrate toward which pole in electrophoresis?

A. Cathode

B. Anode

C. Negative pole

D. Warmer pole

B. Anode

4. What concentration of agarose should be used for optimal separation of DNA fragments of 100, 250, and 350 bp in length?

A. 0.5%

B. 0.7%

C. 2.0%

D. 12.0%

C. 2.0%

5. How does one prepare a 2% agarose gel?

A. Mix 0.01 g agarose/mL running buffer and heat.

B. Mix 0.02 g agarose/mL running buffer and heat.

C. Mix 2 g agarose/mL running buffer and heat.

D. Mix 1 g agarose/mL running buffer and heat.

B. Mix 0.02 g agarose/mL running buffer and heat.

6. Polyacrylamide gel properties can be altered by adjusting T and C values. What are T and C in this context?

A. Temperature of polymerization and concentration of acrylamide

B. Time of polymerization and number of cytosines in the nucleic acid to be separated

C. Total concentration of acrylamide plus cross-linker and percent cross-linker

D. TEMED concentration and concentration of APS used for polymerization

C. Total concentration of acrylamide plus cross-linker and percent cross-linker

7. Which of the following is used to make wells in a solidifying gel into which samples are loaded?

A. Brush

B. Comb

C. Pick

D. Shovel

B. Comb

8. What is one reason that polyacrylamide gels have higher resolution than agarose gels for small fragments?

A. The agarose molecule polymer spaces are bigger than those of polyacrylamide.

B. Agarose polymers are very fragile.

C. Polyacrylamide won't separate molecules over a certain size.

D. Polyacrylamide is a synthetic polymer in which sieving properties can be precisely controlled.

A. The agarose molecule polymer spaces are bigger than those of polyacrylamide.

9. What is an advantage of agarose over polyacrylamide gels?

A. Agarose is more stable than polyacrylamide.

B. Agarose monomers are not toxic.

C. Acrylamide takes a long time to polymerize.

D. Polyacrylamide gels must be used immediately after polymerization.

B. Agarose monomers are not toxic.

10. A very limited amount of nucleic acid, 500 to 1,500 bp in size, is to be analyzed in a short time (same day) with the results available immediately. Which of the following electrophoresis procedures will satisfy those conditions?

A. Capillary electrophoresis

B. Pulsed-field gel electrophoresis

C. Field-inversion gel electrophoresis

D. Contour-clamped homogeneous electric field

A. Capillary electrophoresis

11. Which of the following is an example of pulsed-field gel electrophoresis?

A. Field-inversion gel electrophoresis

B. Isoelectric focusing gels

C. Polyacrylamide gel electrophoresis

D. Capillary gel electrophoresis

C. Polyacrylamide gel electrophoresis

12. A molecular biologist is to separate and analyze a mixture of nucleic acids that are about 100,000 bp in size. Which of the following methods will yield the best results?

A. Capillary electrophoresis

B. Rotating gel electrophoresis

C. Polyacrylamide gel electrophoresis

D. Traditional agarose gel electrophoresis

B. Rotating gel electrophoresis

13. To separate a mixture of oligonucleotides with a resolution between bands of 1 bp, which of the following methods should be used?

A. Contour-clamped homogeneous electric field

B. Rotating gel electrophoresis

C. Polyacrylamide gel electrophoresis

D. Traditional agarose gel electrophoresis

C. Polyacrylamide gel electrophoresis

14. The matrix in capillary electrophoresis through which nucleic acids pass is

A. silica.

B. agarose.

C. agarobiose.

D. optimized polymer.

D. optimized polymer.

15. As compared with traditional slab gel electrophoresis, which of the following is not an advantage of capillary electrophoresis?

A. Analyzes smaller amounts of samples

B. Ability to run more than one sample together

C. Cost of instrumentation and labels

D. Real-time sample detection and analysis

C. Cost of instrumentation and labels

16. Nucleic acids are injected into the capillary in capillary electrophoresis by which of the following injection methods?

A. Hydrostatic

B. Electrokinetic

C. Pneumatic

D. Vacuum

B. Electrokinetic

17. Which of the following molecules will migrate fastest in capillary electrophoresis?

A. Large and positively charged

B. Small and positively charged

C. Large and negatively charged

D. Small and negatively charged

D. Small and negatively charged

18. Which of the following molecules is added to an electrophoresis buffer for the purpose of denaturing DNA?

A. Ethylenediaminetetraacetic acid

B. Polyacrylamide

C. Formamide

D. Tris borate

C. Formamide

19. In order to increase the density of a sample relative to the density of the buffer prior to loading the sample into a gel, which of the following is added to the sample?

A. Glycerol

B. Ethidium bromide

C. Formaldehyde

D. Tris acetate EDTA

A. Glycerol

20. A molecular technologist has run a vertical gel. While analyzing the gel, the technologist notices that the bands in the outer lanes did not run as far as similar-size bands in the inner lanes, resulting in the bands looking like a smile on the gel. What is the explanation for this?

A. Samples were loaded into the inner wells first and got a head start in moving down the gel.

B. A larger volume of sample was loaded into the outer wells, so it ran slower.

C. The electrodes in the middle of the gel were working better than those at the edges of the gel.

D. The temperature across the gel was not constant, so the inner wells were warmer.

D. The temperature across the gel was not constant, so the inner wells were warmer.

21. In order to monitor the progress of electrophoresis, which of the following is added to a sample that does not associate with DNA and runs ahead of the smallest fragments in the sample?

A. Ethidium bromide

B. Acrylamide

C. Bromphenol blue

D. SYBR green

C. Bromphenol blue

22. Which is an important property of electrophoresis gel running buffers?

A. Solubility at low temperature

B. Ability to maintain constant pH

C. Capacity to heat up quickly

D. High absorption of ultraviolet light

B. Ability to maintain constant pH

23. Which of the following can be used to detect the location of DNA bands in a gel after electrophoresis?

A. SYBR green

B. Xylene cyanol green

C. Bromphenol blue

D. Acridine orange

A. SYBR green

24. Which of the following properties is true of ethidium bromide?

A. Emits green light when excited at 300 nm

B. Has a level of detection of 60 pg of DNA

C. Intercalates between nitrogen bases

D. Has a very low background fluorescence in agarose

C. Intercalates between nitrogen bases

25. The functions of which component include carrying the current and protecting the sample nucleic acids during electrophoresis?

A. Polyacrylamide

B. Formaldehyde

C. Ammonium persulfate

D. Tris borate EDTA

D. Tris borate EDTA

26. DNA fragments are detected in capillary electrophoresis by which of the following?

A. Ethidium bromide staining prior to separation

B. Covalently attached fluorescent molecules

C. Soaking the sample in silver stain

D. Colorimetric molecules bound to the DNA

B. Covalently attached fluorescent molecules

27. What is the purpose of urea mixed with the gel for electrophoresis?

A. Enhanced gel stability

B. Optimization of sample nucleic acid staining

C. Inhibition of hydrogen bonding of nucleic acids

D. Blocking of contaminants from entering the gel

C. Inhibition of hydrogen bonding of nucleic acids

28. Which fragment range is most efficiently separated by PFGE?

A. 50 to 1,000 bp

B. 100 to 5,000 bp

C. 500 to 10,000 bp

D. 50,000 to 250,000 bp

D. 50,000 to 250,000 bp

29. How are the large fragments of DNA protected for PFGE separation?

A. Cell lysis in the presence of GITC

B. Mixture of the sample with detergent at low pH

C. Running the sample DNA at a high current

D. Immobilization of the sample in an agarose plug

D. Immobilization of the sample in an agarose plug

30. Which type of detection is used for silver stain?

A. Autoradiography

B. Visible color

C. Fluorometric

D. Ultraviolet excitation

B. Visible color