Tag: cutting, insertion and ligation of dna

Questions Related to cutting, insertion and ligation of dna

Process used for amplification or multiplication of DNA in DNA fingerprinting is

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. Polymerase chain reaction

  2. Southern blotting

  3. Northern blotting

  4. None of these

Show answer
Correct Option: A
Explanation:

Process used for amplification or multiplication of DNA in DNA fingerprinting is Polymerase chain reaction (PCR) .It is done in invitro system.

So, the correct option is 'Option A' . 

Primers are

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. Chemically synthesised oligonucleotides that are complementary to the regions of DNA

  2. Chemically synthesised oligonucleotides that are not complementary to the regions of DNA

  3. Chemically synthesised, autonomously replicating circular DNA molecules

  4. Specific sequences present on recombinant DNA

Show answer
Correct Option: A
Explanation:
Primers are small, chemically synthesised oligonucleotides that are complementary to the sequences, present at 3' end of the template DNA. They hybridise to the target DNA region, one to each strand of the double helix. These primers are oriented with their ends facing each other allowing synthesis of the DNA towards one another.
So, the correct answer is 'Chemically synthesised oligonucleotides that are complementary to the regions of DNA'.

Given table gives an account of differences between PCR and gene cloning. Which of the, following points shows the incorrect difference?

  Parameter PCR Gene cloning
1 Efficient More Less
2 Apparatus Requirement DNA Restriction enzyme, ligase, vector, bacterial cell
3 Manipulation In vitro In vitro and in vivo
4 Cost More Less
5 Automation Yes No
6 Error probability Less More
7 Time for a typical experiment 2-4 days 4 hours
8 Application More Less


bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. 1 and 3

  2. 4 and 6

  3. 4 and 7

  4. 4, 7 and 8

Show answer
Correct Option: C
Explanation:

The cost of gene cloning is far more than PCR because gene cloning requires many intricate steps. PCR takes less than 4 hours while gene cloning can take days.

In a polymerase chain reaction, temperature required for the steps (i) Denaturation,(ii) Annealing, and (iii) Extension are respectively.

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. (i) $94^o$$C$ (ii) $40^o$$C$ (iii) $72^o$$C$

  2. (i) $40^o$$C$ (ii) $72^o$$C$ (iii) $94^o$$C$

  3. (i) $94^o$$C$ (ii) $72^o$$C$ (iii) $40^o$$C$

  4. (i) $72^o$$C$ (ii) $94^o$$C$ (iii) $40^o$$C$

Show answer
Correct Option: A
Explanation:
  • At the start of PCR, the DNA from which a segment is to be amplified, an excess of the two primer molecules, the four deoxynucleoside triphosphates and the DNA polymerase are mixed in the reaction mixture that has appropriate quantities of $Mg^{2+}$. 
  • The reaction mixture is first heated to a temperature between $90-$$98^oC$ (commonly $94^oC$) that ensures DNA denaturation. Every single strand of the target DNA then acts as a template for DNA synthesis. This is the denaturation step. The duration of this step in the first cycle of PCR is usually 2 min at  $94^oC$. 
  • The mixture is now cooled to a temperature (generally $40-60^oC$) that permits annealing of the primer to the complementary sequences in the DNA. This step is called annealing. The duration of the annealing step is usually 1 min.
  • The primers are extended towards each other so that the DNA segment lying between the two primers is copied, this is ensured by employing primers complementary to the 3': ends of the segment to be amplified. The duration of primer extension is usually 2 min at $72^oC$. 

In addition to Taq polymerase enzyme which other thermostable DNA polymerases have been isolated to be used in polymerase chain Reaction (PCR)?

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. Pfu polymerase isolated from Pyrococcus furiosus

  2. Tli polymerase (vent polymerase) isolated from Thermococcus litoralis

  3. Both (a) and (b)

  4. None of these

Show answer
Correct Option: C
Explanation:

In addition to Tag DNA polymerase, Pfu polymerase and Tli polymerase have been isolated which are also thermostable. Pfu polymerase is isolated from Pyrococcus furiosus. Tli (vent) polymerase is isolated from Thermococcus litoralis.

Which one of the following is not a correct match?

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. Tumor Inducing - Ti plasmid

  2. DNA probe - Identifies the desired DNA fragment

  3. PCR - DNA staining

  4. Agarose - Sea weeds

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Correct Option: C

The correct sequence of different steps of polymerase chain reaction is

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. Annealing denaturation extension

  2. Denaturation extension annealing

  3. Denaturation annealing extension

  4. Extension denaturation annealing

Show answer
Correct Option: C
Explanation:
Polymerase chain reaction is a technique used to replicate a fragment of DNA so as to produce many copies of a particular DNA sequence. A single PCR amplification cycle involves three basic steps: denaturation, annealing and extension (polymerisation).
So, the correct answer is 'Denaturation annealing extension'.

A doctor while operating on an HIV(+)ve patient accidentally cuts himself with a scalpel. Suspecting himself to have contracted the virus which test will he take to rule out/confirm his suspicion?

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. PCR

  2. Routine urine examination

  3. TLC

  4. DLC

Show answer
Correct Option: A
Explanation:

Very low count of bacteria or viruses (when the symptoms of the disease are not yet visible) can be detected by multiplication of their nucleic acid by PCR, (PCR can detect very low amounts of DNA). PCR is usually used to detect HIV in suspected AIDS patients.

Given figures represent the steps involved in polymerase chain reaction (PCR). Identify the steps A, B, C and D, and select the correct option.

A B C D
a Denaturation at 94-96 degree C Extension through Taq polymerase at 72 degree C Repetition of denaturation and annealing Annealing at 72 degree C
b Denaturation at 94-96 degree C Annealing at 40-60 degree C Extension through Taq polymerase at 72 degree C Repetition of denaturation and annealing
c Denaturation at 40-60 degree C Annealing at 72 degree C Extension through Taq polymerase at 94-96  degree C Repetition of denaturation and annealing
d Extension through Taq polymerase at 72 degree C Denaturation at 40 degree C Annealing at 72 degree C Repetition of denaturation and annealing
bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. a

  2. b

  3. c

  4. d

Show answer
Correct Option: B
Explanation:

Polymerase chain reaction involves the steps:

  • Denaturation
  • Annealing 
  • Extension
  • Amplification
So, the correct option is 'Option B ' .

Study the following statements regarding recombinant DNA technology and select the incorrect ones

(i) Taq polymerase extends the primers using the nucleotides provided in the reaction
(ii) Antibiotic resistance genes are considered as desirable genes in recombinant DNA technology
(iii) DNA fragments are separated according to their charge only, in agarose gel electrophoresis
(iv) Transformation is a procedure through which a piece of DNA is integrated into the genome of a host bacterium
(v) To produce higher yields of the desired protein, host cells can be multiplied in a continuous culture
(vi) Downstream processing is one of the steps of polymerase chain reaction

bio-chemistry applications of biotechnology pcr cutting, insertion and ligation of dna gene cloning procedure biotechnological regulations asexual modes of reproduction

  1. (i), (iii) and (vi)

  2. (i), (iii) and (v)

  3. (ii), (iii) and (v)

  4. (i), (iv) and (v)

Show answer
Correct Option: A
Explanation:

Antibiotic resistance genes are selectable markers. Desirable genes are the ones which are introduced in the vector for getting desired protein product. In agarose gel electrophoresis, DNA fragments are separated according to their charge and size. After the formation of the product in a bioreactors, it undergoes through some processes before a finished product is ready for marketing. The processes include separation and purification of products which are collectively called as downstream processing.