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प्रश्न
| 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.
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उत्तर
(a) You can easily grow a large quantity of the bacteria/no ethical issues/have plasmids/can easily transform.
(b) PCR will not amplify the gene.
If the polymerase enzyme denatures at low temperatures, it will not be able to withstand high temperatures which is essential for separating/opening/unwinding/denaturing DNA strands to open. Thus subsequent step of extending the primers using the nucleotides provided in the reaction and the genomic DNA as the template will not occur.
(c) Positive effect: Oil spills can be treated and the environment becomes better/cleaner/water becomes more potable/safe for aquatic forms/safe for water birds like seagulls.
Negative effect: The bacteria can mutate/can harm other organisms/can conjugate with other non-virulent forms and make them super-bugs with detrimental effects/unpredictable/for a longer duration it may reduce the dissolved oxygen and lead to mortality of aquatic organisms.
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संबंधित प्रश्न
Name the genes responsible for making Bt cotton plants resistant to bollworm attack. How do such plants attain resistance against bollworm attacks? Explain.
The technique which involves addition or deletion of genes is ______.
For which of the following purpose restriction endonuclease enzyme is used in genetic engineering?
Which of the following is the right combination of primers in a PCR to amplify the DNA product?
Which of the following is NOT involved in genetic engineering technique?
i. Combining genes from two organisms
ii. Gene cloning
iii. Transfer of lipid molecules
iv. Transfer of genes to new organisms
v. Repairing or replacing the defective genes by healthy genes
vi. Artificial synthesis of new gene
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?
Which of the following enzyme catalyses the removal of nucleotides from the end of DNA molecules?
Study the following lists and choose the correct match.
| List I | List II |
| A. Vector | (i) Resistant to cotton bollworms |
| B. Downstream processing | (ii) Mobile genetic elements |
| C. Cry II AB | (iii) Controls corn borers |
| D. Transposons | (iv) Ti plasmid |
| (v) Purifying protein in biopharmaceuticals |
The structure below shows pUC18, which is similar to pBR322 in its function. However, they differ in some of their restriction sites and the number of ori. The ori number for pBR322 is approximately 20.

- How are puc18 and pBR322 used in biotechnological studies?
OR
What will be the impact if the ori in the above structure gets damaged? - The lac z gene has many recognition sites. Study the segment of DNA given below and answer the questions.
5’... ATC GTA AAG CTT CAT…3’
3’... TAG CAT TTC GAA GTA…5’
i) Applying your knowledge of palindrome sequences identify and mark the possible region where the restriction enzyme X will act.
ii) Restriction enzyme Y was used to extract a gene of interest from a plant. This gene needs to be inserted in the given DNA segment which has been treated with restriction enzyme X. Will there be a successful recombination? Explain with a reason. - Which one of the two (pUC18 and pBR322) would you prefer for biotechnological studies? Justify.
Give a reason for the following:
DNA cannot enter directly into the host cell.
