Gel Electrophoresis

Q. The first recombinant DNA was constructed by

1. Stanley Cohen
2. Herbert Boyer
3. Both (a) and (b)
4. Temin and Baltimore

Q. At which end of the gel the sample was loaded in gel electrophoresis?

Q. A plasmid DNA and a linear DNA (both are of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band while linear DNA shows two fragments. Explain.

Q. In agarose gel electrophoresis:

1. DNA migrates towards the negative electrode
2. Supercoiled plasmids migrate slower than their nicked counterparts
3. Larger molecules migrate faster than smaller molecules
4. Ethidium bromide can be used to visualize the DNA

Q.

How are transformants selected from non-transformants?

Q.

Name and explain techniques used in the separation and isolation of DNA fragments to be used in recombinant DNA technology?

Q. DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by

1. centrifugation
2. polymerase chain reaction
3. electrophoresis
4. restriction mapping

Q. A circular double-stranded DNA molecule of 45kb size has two restriction sites for EcoRⅠ and one for HindⅢ. All of them are equidistant from each other. Upon incubation with both the restriction enzymes _____ band(s) appear in the gel electrophoresis.

1. 3
2. 4
3. 1
4. Insufficient data

Q. Sandy was conducting gel electrophoresis in his laboratory. However, he wanted to try something new. He placed the gel in the tank in such a way that the wells were placed towards the anode. What can be the likely consequence of the loaded DNA sample?

1. DNA fragments were separated normally
2. DNA fragments migrated towards the cathode
3. DNA fragments did not show usual migration towards anode
4. Both a and b can be possible

Q. DNA is digested with a restriction endonuclease and subjected to gel electrophoresis.
Choose the correct statement w.r.t. to the above, among the following:

1. DNA fragments will migrate towards the cathode
2. Number of bands equals the number of restriction sites within the DNA
3. DNA fragments will migrate towards the anode
4. There is no correlation between the number of bands on the agarose gel and restriction sites in the DNA

Q. Which among the following are components of the agarose gel electrophoresis apparatus?

1. Buffer, icepack, chamber
2. Nylon membrane, powerpack, electrophoresis tank
3. Electrophoresis unit and power supply
4. Power pack, nylon membrane, capillary tube

Q.

Identify the correct sequence of steps involved in the process of gel electrophoresis:

1. Elution of band for getting Gene of Interest

2. Turning on the power

3. Comb removal

4. Sample loading in the wells

5. Cooling the wells

6. Gel casting

7. Forming wells using comb

8. Gel preparation

1. 8, 6, 7, 5, 3, 4, 1, 2
2. 8, 6, 7, 5, 3, 2, 4, 1
3. 8, 6, 7, 5, 3, 4, 2, 1
4. 8, 6, 7, 3, 5, 4, 2, 1

Q. The advantage of using agarose gel in separating DNA is that it

1. provides sieving effect which helps to separate the DNA molecules
2. creates an electric field to help the migration of DNA molecules
3. creates a concentration gradient to allow the diffusion of DNA molecules
4. provides a cool environment to help separate the DNA molecules

Q. During isolation of genetic material, the chemical used to precipitate out the purified DNA is

1. bromophenol blue
2. chilled ethanol
3. ethidium bromide
4. both a and c

Q. A double-stranded DNA sample when separately incubated with EcoRⅠ and Hind Ⅱ, produces a single band at 10.2 kb in agarose gel electrophoresis.
Based on the above information which of the following statements is correct?

1. DNA contains two sites for EcoR Ⅰ
2. It is a double-stranded linear DNA
3. It is a double-stranded circular DNA
4. Restriction sites are equidistant from each other

Q. Read the following statements:

(i) Primers used in PCR are small chemically synthesized oligosaccharides
(ii) E. coli is closely related to Salmonella
(iii) There are 3 basic steps in genetically modifying an organism
(iv) The techniques of the genetic engineering overcome the limitation of traditional hybridisation procedures

In these statements how many are correct?

1. 4
2. 3
3. 1
4. 2

Q. The basis for the separation and resolution of DNA fragments on agarose gel electrophoresis is-
a. Charge on DNA
b. Size of the DNA fragments
c. Movement towards cathode
Choose the correct option.

1. (a) only
2. (a) and (c)
3. (b) and (c)
4. (a), (b) and (c)

Q.

Explain briefly

(a) PCR

(b) Restriction enzymes and DNA

(c) Chitinase

Q. In a mixture, DNA fragments are separated by:

1. Restriction digestion
2. Electrophoresis
3. Polymerase chain reaction
4. Bioprocess engineering

Q. Separation of DNA by gel electrophoresis is based on .

1. charge of gel
2. strand size
3. order of bases

Q. For the preparation of agarose gel in electrophoresis, agarose is dissolved in

1. TAE buffer
2. Distilled water
3. Oil based emulsion
4. Alcohol

Q.

How is gel electrophoresis used in DNA fingerprinting?

Q. How many DNA fragments will be obtained on the digestion of a linear DNA and a circular DNA with a type of restriction enzyme having four recognition sites in both the DNA molecules?

Q. Study the given figure carefully and select the incorrect statements regarding this.(i) It represents a typical agarose gel electrophoresis in which lane 1 contains undigested DNA(ii) Smallest DNA bands are formed at A and largest DNA bands are formed at B(iii) The separated DNA fragments can be visualized after staining in the visible light(iv) The separated DNA bands are cut out from the agarose gel and extracted from the gel piece. This step is known as elution.

1. (i) and (ii)
2. (ii) and (iii)
3. (ii) and (iv)
4. (i) and (iv)

Q. Researchers sometimes use chromatography as a method to separate biomolecules. Why is electrophoresis used and not chromatography for separating DNA molecules?

1. Chromatography cannot be performed for separating charged molecules
2. Chromatography is used only for coloured substances
3. Electrophoresis is faster when compared to chromatography
4. DNA is negatively charged and hence can be easily separated using electric charge

Q. A person obtains transformants by inserting the desired gene within the coding sequence of enzyme 𝛃-galactosidase. Which of the following observations will help him separate out recombinants from non-recombinants?

1. Non-recombinant colonies do not produce any colour while recombinants give blue coloured colonies
2. Recombinant colonies do not produce any colour while non-recombinants give blue coloured colonies
3. Both recombinants and non-recombinants produce blue-coloured colonies
4. No colonies are formed due to insertional inactivation

Q. The separated DNA fragments by gel electrophoresis can be visualised only after staining the DNA with a compound known as

1. ethidium iodide
2. ethidium chloride
3. ethidium bromide
4. propidium iodide

Q.

What is the criterion for DNA fragment movement?

Q. DNA fragments generated by restriction endonucleases in a chemical reaction can be separated by

1. Restriction mapping
2. Centrifugation
3. Polymerase chain reaction
4. Agarose gel electrophoresis

Q. Which one of the following statement is not true regarding gel electrophoresis technique?