EtBr Usage

Q.

DNA strands on a gel stained with ethidium bromide when viewed under UV radiation, appear as

1. Yellow bands

2. Dark red bands

3. Bright blue bands

4. Orange bands

Q. The stain used to visualize mitochondria is

1. Fast Green
2. Safranin
3. Acetocarmine
4. Janus Green

Q.

What is the role of ethidium bromide in DNA samples?

Q. DNA staining by ethidium bromide is followed by the exposure to UV rays. Now DNA is seen as bands of :

1. Blue colour
2. Orange colour
3. Red colour
4. Both B and C

Q. Which of the following statements is correct in the context of observing DNA separated by agarose gel electrophoresis?

1. Ethidium bromide stained DNA can be seen in visible light
2. DNA can be seen in visible light
3. DNA can be seen without staining in visible light
4. Ethidium bromide stained DNA can be seen under exposure to UV light

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 bromide
3. ethidium chloride
4. propidium iodide

Q. Assertion (A): Ethidium bromide (EtBr) helps in visualizing DNA in UV light only
Reason (R): This intercalating agent absorbs light in range 500-700 nm

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. Both A and R are false

Q. In her practical exams, Asha was provided with a sample of scraped cells from the human buccal cavity. She, very carefully, extracted the genomic DNA, amplified the desired DNA and ran gel electrophoresis. However, she was utterly disappointed as she could not find the DNA bands herself. However, she scored full marks in her practical. What can be the possible reason as to which Asha was not able to see the bands that the teacher could find out?

1. She did not use ethidium bromide
2. She was observing the gel by exposing it to incandescent bulb
3. She placed the gel on the electrophoresis unit such that the wells were towards the positive terminal of the power supply
4. She did not isolate the DNA properly

Q. is iodine a stain can it be used to see different parts of cell?

Q. A molecular biologist used restriction enzyme for digesting a specific sequence of DNA, which molecular biology procedure he would be using to separate the DNA fragments?

1. Agaraose gel electrophoresis
2. ELISA
3. DNA fingerprinting
4. Southern blotting

Q. is used for staining to visualise DNA in a gel.

1. NaOH
2. EtBr
3. HCl
4. Agarose

Q. How does one visualize DNA on an agar gel?

Q. Which technique is used in separating fragments of DNA ______________.

1. Eastern blotting
2. Western blotting
3. Northern blotting
4. Southern blotting

Q. State a method of cellular defense which works in plant cell.

Q. A correct pair of characteristics of molecular probe are:
a. Very long molecule
b. Double stranded
c. DNA or RNA
d. Complementary to a part of desired gene.

1. a, b
2. b, c
3. c, d
4. d, a

Q. is used for staining to visualise DNA in a gel.

1. NaOH
2. EtBr
3. HCl
4. Agarose

Q. Which of the following steps should be performed in order to visualize the bands of DNA fragments by gel electrophoresis?

1. Exposure of DNA fragments to UV radiations
2. Staining with bromophenol blue followed by exposure to UV radiations
3. Staining with ethidium bromide followed by exposure to UV radiations
4. Staining with ethidium bromide

Q. Assertion (A): Ethidium bromide (EtBr) helps in visualizing DNA in UV light only
Reason (R): This intercalating agent absorbs light in range 500-700 nm

1. Both A and R are true and R is the correct explanation of A
2. A is true but R is false
3. Both A and R are false
4. Both A and R are true but R is not the correct explanation of A

Q. What is the role of EtBr in recombinant DNA technology?

1. It separates the DNA from the gel matrix
2. It sticks to DNA and imparts a deep red color
3. It helps the DNA move through the gel matrix
4. It sticks to DNA and fluoresces under UV rays

Q. The DNA fragments separated on an agarose gel can be visualised after staining with:

1. Bromophenol blue
2. Acetocarmine
3. Aniline blue
4. Ethidium bromide

Q. The DNA fragments separated on an agarose gel can be visualised after staining with :

1. Bromophenol blue
2. Acetocarmine
3. Aniline blue
4. Ethidium bromide

Q. Which of the following steps should be performed in order to visualize the bands of DNA fragments by gel electrophoresis?

1. Exposure of DNA fragments to UV radiations
2. Staining with bromophenol blue followed by exposure to UV radiations
3. Staining with ethidium bromide followed by exposure to UV radiations
4. Staining with ethidium bromide

Q. a) How do DNA fragments migrate and resolve in a Gel electrophoresis?
b) How lane one is different from lane 2, 3 and 4 in the Gel electrophoresis set up?
c) How pure DNA fragments are made observable in the visible light?