Tag: bio-chemistry

Questions Related to bio-chemistry

In DNA segment of six coils, 22 bp are linked by two hydrogen bonds. How many cytosine bases would be present

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. 22

  2. 38

  3. 44

  4. 76

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Correct Option: B

In a DNA fragment, there are 8 turns with 40% of the bases are cytosine. What would be the number of hydrogen bonds present in this DNA fragment 

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. 96

  2. 192

  3. 224

  4. 60

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Correct Option: C

Which one of the following statements is wrong with respect to separation of DNA fragments on gel electrophoresis

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. DNA fragments move towards anode under electric field through the matrix

  2. The commonly used matrix is agarose gel

  3. DNA fragments resolve according to their size

  4. The smaller DNA fragments separate first

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Correct Option: D

Escherichia coli, in which both the strands of DNA are labeled  with $^{15}N$ is transferred to $^{14}N$ medium and allowed to replicate for three generations. Find out the number of hybrid DNA molecules in the third generation

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. 8

  2. 2

  3. 12

  4. 10

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Correct Option: B

Fragments of DNA formed after treatment with endonucleases are separated by the technique

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. Polymerase chain reaction

  2. Southern blotting

  3. Colony hybridisation

  4. Electrophoresis

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Correct Option: D

First step in Southern blot technique is

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. Digestion of DNA by restriction enzyme

  2. Production of a group of genetically identical cells

  3. Denaturation of DNA on the gel for hybridisation with specific probe

  4. Denaturation of DNA from a nucleated cell as from the scene of crime

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Correct Option: A
Explanation:

The first step in a Southern blot technique is to prepare the DNA mixture by breaking it into smaller fragments using a restriction enzyme.

In gel electrophoresis, differential mobility of DNA depends upon

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. Helical nature of DNA

  2. Double stranded nature of DNA

  3. Charge and size of DNA

  4. Hydrogen bonding between bases

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Correct Option: C

The term southern blotting refers to

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. Transfer of DNA fragments from in vitro cellulose membrane to electrophoretic gel

  2. Attachment of probes to DNA fragments

  3. Transfer of DNA fragments from electrophoretic gel to nitrocellulose sheet

  4. Comparison of DNA fragments from two sources

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Correct Option: B

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.

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. a,b

  2. b,c

  3. c,d

  4. d,a

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Correct Option: C

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

bio-chemistry biochemical techniques manipulation of dna electrophoresis isolation and separation of dna

  1. Restriction mapping

  2. Centrifugation

  3. Polymerase chain reaction

  4. Agarose gel electrophoresis

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Correct Option: D