Tag: biochemical techniques

Quizzes (6) Questions (139)

Questions Related to biochemical techniques

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

The term southern blotting refers to

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

Southern blotting is a laboratory technique used to detect specific DNA sequences in DNA samples. It involves transferring separated DNA fragments from an agarose gel to a nitrocellulose or nylon membrane for hybridization probing.

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'.

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

What is the function of gel electrophoresis in genetic engineering?

  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
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.

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

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

  1. electrophoresis

  2. restriction mapping

  3. centrigugation

  4. polymerase chain reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
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'.