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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
Draw a labelled sketch of sparged-stirred-tank bioreactor. Write its application.
From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?
Describe briefly the following:
Bioreactors
Describe briefly the following:
Downstream processing
Explain briefly:
Chitinase
State the importance of using a bioreactor.
In a pathological lab, a series of steps were undertaken for finding the gene of interest. Describe the steps, or make a flow chart showing the process of amplification of this gene of interest.
Which of the following term used for defining a viral genome incorporated into host DNA?
DNA fragments generated by the restriction endonuclease in a chemical reaction can be separated by ______.
The first step in recombinant DNA technology is
In PCR, primers are used for ______.
During the purification process for recombinant DNA technology, the addition of chilled ethanol precipitates out ______.
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?
Which of the following steps are catalysed by Taq DNA polymerase in a PCR reaction?
How is copy number of the plasmid vector related to yield of recombinant protein?
Identify and explain steps ‘A’, ‘B’ and ‘C’ in the PCR diagram given below.
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.
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. |
- Name the human disease for which the gene therapy was used for the first time.
- 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?
- 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:
- 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.
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:
Main steps in the formation of Recombinant DNA are given below. Arrange these steps in a correct sequence.
- Insertion of recombinant DNA into the host cell.
- Cutting of DNA at specific location by restriction enzyme.
- Isolation of desired DNA fragment.
- Amplification of gene of interest using PCR.
Choose the correct answer from the options given below:
Upon exposure to UV radiation, DNA stained with ethidium bromide will show ______.
