Tag: manipulation of dna

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

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

  1. Polymerase chain reaction

  2. Southern blotting

  3. Colony hybridisation

  4. Electrophoresis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Gel electrophoresis is the standard laboratory technique used to separate DNA fragments based on their size and charge after they have been cut by restriction endonucleases.

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

First step in Southern blot technique is

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

In gel electrophoresis, differential mobility of DNA depends upon

  1. Helical nature of DNA

  2. Double stranded nature of DNA

  3. Charge and size of DNA

  4. Hydrogen bonding between bases
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

DNA is negatively charged due to its phosphate backbone, so it moves toward the anode. The gel matrix acts as a sieve, where smaller fragments move more easily than larger ones, meaning separation depends on both charge and size.

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

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
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A molecular probe is a single-stranded DNA or RNA molecule that is complementary to the target sequence of interest, allowing it to bind specifically to that sequence.

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

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
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Agarose gel electrophoresis is the standard technique used to separate DNA fragments of varying lengths generated by restriction endonuclease digestion.

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

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?

  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. $3'\quad ATTAGCTAGCAA\quad 5'\\ 5'\quad TAATCGATCGTT\quad 3'$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA melting temperature is higher for sequences with more G-C base pairs because G-C pairs have three hydrogen bonds, while A-T pairs have only two. Option C contains the highest proportion of G-C pairs, requiring the most energy to separate.

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

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

  1. Infection by Agrobacterium

  2. Microinjection

  3. Electrophoresis

  4. Infection by bacteriophage
Reveal answer Fill a bubble to check yourself
C Correct answer
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'.