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प्रश्न
Explain briefly:
PCR
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उत्तर
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:
- Denaturation: Heating the double-stranded DNA to around 94°C to separate it into single strands.
- Annealing: Cooling to 46-60°C to allow short primers to bind to complementary sequences on the single-stranded DNA.
- 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.
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संबंधित प्रश्न
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).
From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
Can you recall meiosis and indicate at what stage recombinant DNA is made?
Explain briefly:
Chitinase
State the importance of using a bioreactor.
Prepare a flow chart in formation of recombinant DNA by the action of restriction endonuclease enzyme EcoRI.
Describe the process of amplification of the “gene of interest” using the PCR technique.
Which of the following term used for defining a viral genome incorporated into host DNA?
______ plays an important role in blood clotting.
DNA fragments generated by the restriction endonuclease in a chemical reaction can be separated by ______.
PCR and restriction fragment length polymorphism are the methods for ______.
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?
In PCR, primers are used for ______.
During the process of gene amplification using PCR, if a very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first?
Rising of dough is due to ______.
Which of the following steps are catalysed by Taq DNA polymerase in a PCR reaction?
Read the paragraph given below and answer and questions that follow:
| Enzyme Taq polymerase, is extracted from a eubacterial microorganism Thermus aquaticus from Yellowstone National Park in Montana, USA and isolated by Chien et al. (1976). Taq polymerase successfully replaced the DNA polymerase from E.coli that was being used in PCR earlier and this shift revolutionised the PCR technique. |
- Taq polymerase after its discovery replaced E.coli DNA polymerase in PCR technique. Explain giving reasons why was the need felt for the change?
- What is a primer and its importance in PCR?
- Write the importance of PCR as a diagnostic tool.
Assertion (A): Synthetic oligonucleotide polymers are used during Annealing in a PCR.
Reason (R): The primers bind to the double stranded DNA at their complementary regions.
State the advantage of using Thermostable DNA polymerase.
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:
- List the operational guidelines that must be adhered to so as to achieve optimisation of the bioreactor system. Enlist any four.
- Mention the phase of the growth we refer to in the statement "Optimisation of growth and metabolic activity of the cells".
- Is the biological product formed in the bioreactor suitable for the intended use immediate? Give reason in support of your answer.
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 ______.
