Tag: biochemical techniques

Questions Related to biochemical techniques

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

When heated, the hydrogen bonds between the complementary strands of DNA break and the 2 strands separate in a process called melting. Which of the following pieces of DNA will require maximum temperature for melting?

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

  1. $3'\quad AAGGTATACAAT\quad 5'\ 5'\quad TTCCATATGTTA\quad 3'$

  2. $3'\quad GAGCUAUCCGAG\quad 5'\ 5'\quad CUCGAUAGGCUC\quad 3'$

  3. $3'\quad ACGTCCGCTGCG\quad 5'\ 5'\quad TGCAGGCGACGC\quad 3'$

  4. $3'\quad ATTAGCTAGCAA\quad 5'\ 5'\quad TAATCGATCGTT\quad 3'$

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Correct Option: A

E.coli which was grown in the medium containing heavy isotope $ {  }^{ 15 }{ N }$ for several generations is shifted to normal $ _{  }^{ 14 }{ N }$ medium, the percentage of DNA strands with $ _{  }^{ 14 }{ N }$ isotope after two generations is _____________.

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

  1. $12.5$%

  2. $50$%

  3. $75$%

  4. $100$%

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Correct Option: A

When a sample containing antibody $1\ gM$ is run on SDS - PAGE, what molecular weight bands are expected to be seen?

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

  1. $70, 55. 15\ Kbp$

  2. $50, 15\ Kbp$

  3. $50, 55\ Kbp$

  4. $50, 25\ Kbp$

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Correct Option: A

Which of the following is not a technique for introducing recombinant DNA into host cells?

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

  1. Infection by Agrobacterium

  2. Microinjection

  3. Electrophoresis

  4. Infection by bacteriophage

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Correct Option: C
Explanation:

There are special techniques for the introduction of recombinant DNA into host cells. Microinjection, biolistics, infection by disarmed pathogens like Agrobacterium or bacteriophage are examples of such techniques. 

While electrophoresis is used for the separation of various DNA segments based on their length. 
So, the correct option is 'Electrophoresis'.

What is the function of gel electrophoresis in genetic engineering?

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

  1. Cut DNA into many fragments

  2. Link together newly joined fragments of DNA

  3. Make millions of copies of a specific segment of DNA

  4. Separate fragments of DNA by their length and electrical charges

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Correct Option: D
Explanation:

Gel electrophoresis is a technique used to separate DNA fragments according to their size. DNA samples are loaded into wells (indentations) at one end of a gel, and an electric current is applied to pull them through the gel. DNA fragments are negatively charged, so they move towards the positive electrode. 

So, the correct option is 'Separate fragments of DNA by their length and electrical charges'.

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

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

  1. electrophoresis

  2. restriction mapping

  3. centrigugation

  4. polymerase chain reaction

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Correct Option: A
Explanation:

Gel electrophoresis is a method for separation and analysis of macromolecules (DNA, RNA and proteins) and their fragments, based on their size and charge. It is used in molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge.


Nucleic acid molecules are separated by applying an electric field to move the negatively charged molecules through a matrix of agarose or other substances. Shorter molecules move faster and migrate farther than longer ones because shorter molecules migrate more easily through the pores of the gel. This phenomenon is called sieving.

DNA Gel electrophoresis is usually performed for analytical purposes, often after amplification of DNA via polymerase chain reaction (PCR), but may be used as a preparative technique prior to use of other methods such as mass spectrometry, RFLP, PCR, cloning, DNA sequencing, or Southern blotting for further characterization.

So the correct option is 'Electrophoresis'.