English
Karnataka Board PUCPUC Science 2nd PUC Class 12

Explain briefly: PCR

Advertisements
Advertisements

Question

Explain briefly:

PCR

Explain
Advertisements

Solution

PCR (Polymerase Chain Reaction) is a technique used to create multiple copies of a specific DNA segment in vitro. It amplifies DNA by repeated cycles of three steps:

  1. Denaturation: Heating the double-stranded DNA to around 94°C to separate it into single strands.
  2. Annealing: Cooling to 46-60°C to allow short primers to bind to complementary sequences on the single-stranded DNA.
  3. Extension: Raising the temperature to about 72°C so a heat-stable DNA polymerase (Taq polymerase) synthesizes new complementary strands, duplicating the target DNA.

Repeating these cycles exponentially amplifies the DNA segment, producing millions of copies rapidly. PCR is widely used for DNA amplification, genetic fingerprinting, disease detection, DNA sequencing, and molecular mapping. It was introduced by Kary Mullis in 1985 and relies on the thermostable enzyme from Thermus aquaticus to function at high temperatures without being denatured.

shaalaa.com
  Is there an error in this question or solution?
Chapter 9: Biotechnology : Principles and Processes - EXERCISES [Page 176]

APPEARS IN

NCERT Biology [English] Class 12
Chapter 9 Biotechnology : Principles and Processes
EXERCISES | Q 11. (a) | Page 176
Nootan Biology [English] Class 12 ISC
Chapter 11 Principles and Processes of Biotechnology
NCERT EXERCISES WITH ANSWERS | Q 10. (a) | Page 536

RELATED QUESTIONS

Name two commonly used bioreactors.


Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.


Draw a labelled sketch of sparged-stirred-tank bioreactor. Write its application.


Can you list 10 recombinant proteins which are used in medical practice? Find out where they are used as therapeutics (use the internet).


Explain briefly:

Chitinase


Prepare a flow chart in formation of recombinant DNA by the action of restriction endonuclease enzyme EcoRI.


Answer the following question:
Describe the formation of recombinant DNA by the action of EcoRI.


Which of the following term used for defining a viral genome incorporated into host DNA?


______ plays an important role in blood clotting.


A single strand of nucleic acid tagged with a radioactive molecule is called ______.


PCR proceeds mthree distinct steps governed by temperature, they are in order of ______.


Blood stains are found at the site of a murder. It DNA profiling technique is to be used for identifying the criminals, which of the following is ideal for use?


An antibiotic resistance gene in a vector usually helps in the selection of ______.


A bacterial cell was transformed with a recombinant DNA molecule that was generated using a human gene. However, the transformed cells did not produce the desired protein. Reasons could be ______.


Which of the following should be chosen for best yield if one were to produce a recombinant protein in large amounts?


While doing a PCR, ‘denaturation’ step is missed. What will be its effect on the process?


Do biomolecules (DNA, protein) exhibit biological activity in anhydrous conditions?


Identify and explain steps ‘A’, ‘B’ and ‘C’ in the PCR diagram given below.


Illustrate the design of a bioreactor. Highlight the difference between a flask in your laboratory and a bioreactor which allows cells to grow in a continuous culture system.


Read the following paragraph and answer the questions that follow:

Biotechnology revolves around the "gene of interest", with an objective to open various avenues for human welfare in health, medicine, pharma, agriculture etc. using different techniques, tools and processes. One of the breakthroughs of biotechnology in medicine is the gene therapy.
  1. Name the human disease for which the gene therapy was used for the first time.
  2. Explain the steps of gene therapy carried to cure the disease using the lymphocytes of the patient. Why is this therapy not a permanent cure of the disease?
  3. Write the possible permanent cure of the disease by the gene therapy that is in progress. 

Bioreactors are the containment vehicles of any biotechnology-based production process. For large scale production and for economic reasons the final success of biotechnological process depends on the efficiency of the bioreactor.

Answer the following questions w.r.t. the given paragraph:

  1. List the operational guidelines that must be adhered to so as to achieve optimisation of the bioreactor system. Enlist any four.
  2. Mention the phase of the growth we refer to in the statement "Optimisation of growth and metabolic activity of the cells".
  3. Is the biological product formed in the bioreactor suitable for the intended use immediate? Give reason in support of your answer.

Identify the part of a bio-reactor which is used as a foam braker from the given figure.


Given below are two statements:

Statement I: The DNA fragments extracted from gel electrophoresis can be used in construction of recombinant DNA.

Statement II: Smaller size DNA fragments are observed near anode while larger fragments are found near the wells in an agarose gel.

In the light of the above statements, choose the most appropriate answer from the options given below:


Which of the following statements is incorrect?


Upon exposure to UV radiation, DNA stained with ethidium bromide will show ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×