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प्रश्न
Name and explain the technique used for separating DNA fragments and making them available for biotechnology experiments.
Name and describe the technique that helps in the separation and isolation of DNA fragments.
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उत्तर
Gel electrophoresis is a technique which is used for separating DNA fragments in a gel on the basis of their electric charge and size.
The process of gel electrophoresis is as follows:
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The fragments obtained after cutting with restriction enzymes are separated by using gel electrophoresis.
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Electric field is applied to the agarose gel matrix and the negatively-charged DNA fragments move towards the anode.
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Fragments separate according to their size by the sieving properties of agarose gel. The smaller the fragment, the farther it moves.
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Staining dyes such as ethidium bromide, upon exposure to UV radiation, are used to visualise the DNA fragments.
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DNA fragments are visible as bright orange-coloured bands in the agarose matrix.
- These bands are cut from the agarose gel and extracted from the gel piece (elution).
- DNA fragments are purified and used in constructing recombinant DNAs
संबंधित प्रश्न
State the role of DNA ligase in biotechnology.
Explain the mechanism of action of restriction endonucleases that makes them suitable for genetic engineering.
The bacterium which causes a plant disease called crown gall is _______________.
In vitro amplification of DNA or RNA segment is known as ___________.
The enzyme restriction endonuclease ______.
Alu-I is obtained from which organism?
What is PCR? Explain different steps involved in it.
Match the List I with List II and List ill. Select the correct option.
| List I | List II | List ill | |||
| i. | Hind III | a. | Agarose ge | 1. | Six base pairs |
| ii. | pBR322 | b. | Agrobacterium | 2. | Selectable marke |
| iii. | T-DNA | c. | Ampicillin | 3. | Elution |
| iv. | DNA | d. | Recognition sequenc | 4. | Transgenic plant |
Identify the properties that a cloning vector must possess to be efficiently used in rDNA technology.
- Control elements like promoter, operator, ribosomal binding sites
- Restriction sites
- Marker genes
- Ori of replication
- Ability to replicate independently
____________ cuts the DNA within the specific positions.
______ is the soil bacterium that causes crown gall characterized by tumors in plants.
Study the following statements regarding separation of DNA using agarose gel electrophoresis.
- Large fragments of DNA molecules move faster than small DNA fragments and thus separate faster.
- DNA being negatively charged migrates to cathode.
Polymerase Chain Reaction is made possible by ____________.
In PCR technique, the organism providing thermostable DNA polymerase is a ____________.
Exonuclease performs the function of ____________.
Nucleic acid segment tagged with a radioactive molecule is called ______.
Name a recombinant vaccine that is currently being used in vaccination programme.
| Oil spill is a major environmental issue. It has been found that different strains of Pseudomonas bacteria have genes to break down the four major groups of hydrocarbons in oil. Trials are underway to use different biotechnological tools to incorporate these genes and create a genetically engineered strain of Pseudomonas - a ‘super-bug’, to break down the four major groups of hydrocarbons in oil. Such bacteria might be sprayed onto surfaces polluted with oil to clean thin films of oil. |
(a) List two advantages of using bacteria for such biotechnological studies?
(b) For amplification of the gene of interest PCR was carried out. The PCR was run with the help of polymerase which was functional only at a very low temperature. How will this impact the efficiency of the PCR? Justify.
(c) If such bacteria are sprayed on water bodies with oil spills, how will this have a positive or negative effect on the environment? Discuss.
Observe the given sequence of nitrogenous bases on a DNA fragments and answer the following questions:
5' - CAGAATTCTTA - 3'
3' - GTCTTAAGAAT - 5'
- Name a restriction enzyme which can recognise this DNA sequence.
- Write the sequence after digestion.
- Why are the ends generated after digestion called sticky ends?
