The correct sequence of steps involved in polymerase chain reaction (PCR) are:
A. DNA polymerase is used to extends the primers using oligonucleotides.
B. Desired DNA fragments are denatured.
C. Amplified fragments are ligated with the vector for cloning.
D. Oligonucleotides are added
Choose the correct answer from the options given below:

Read the following passage carefully and answer the given questions.
Plasmodium, a tiny protozoan is responsible for the disease malaria. Different species of Plasmodium (P. vivax, P. malaria and P. falciparum) are responsible for different types of malaria. Of these, malignant malaria caused by Plasmodium falciparum is the most serious one and can even be fatal. Innate immunity consist of four types of barriers. These are – (i) Physical barriers- skin on our body is the main barrier which prevents entry of the micro-organisms. (ii) Physiological barriers- Acid in the stomach, saliva in the mouth, tears from eyes-all prevent microbial growth. (iii) Cellular barriers- Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes. (iv) Cytokine barriers- virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection. Allergy is due to the release of chemicals like histamine and serotonin from the mast cells. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy. Drugs like barbiturates, amphetamines, benzodiazepines, and other similar drugs, that are normally used as medicines to help patients cope with mental illnesses like depression and insomnia, are often abused.
Malignant malaria is caused by _____ is the most serious one and can even be fatal.

Identify the statements which hold true for transgenic animals.
(A) Transgenic animals can be used to study vaccine safety.
(B) Over 95% of transgenic animals are mice
(C) Transgenic animals cannot be used to study human diseases
(D) Transgenic animal possess and express forgein gene

Identify the correct sequence of stages in the process of decomposition.
(A) Humification
(B) Fragmentation
(C) Catabolism
(D) Mineralisation
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The condition where one species is harmed whereas the other is unaffected is called.

Identify the features developed by flowering plants to discourage self-pollination:
(A) Self incompatibility
(B) Synchronized pollen release and stigma receptivity
(C) Different positions of anther and stigma in a flower
(D) Producing bisexual flowers
Choose the correct answer from the options given below:

Answer the following questions feom the diagram given below :-

The samples in different lanes are from different sources but treated with a common restriction endonuclease. The maximum number of restriction sites are present in

The Mediterranean orchid Ophrys employs 'sexual deceit mechanism to get pollination done by

The correct relation for determining the molar mass of solute (\(\text{M}_2\))
using osmotic pressure measurement, is

If \(C(x)=a x^ 2-bx-c\) represents the total cost function then the slope of the tangent to the marginal cost curve at the point \((x, y)\) is:

Microbes in human welfare Microbes are a very important component of life on earth. we use microbes and microbially derived products almost every day, like LAB to make curd, yeast to make bread, adding flavor and texture to cheese, producing antibiotics etc. The addition of LAB, improves the milk quality by increasing vit. B12. Cheese is one of the oldest food items in which microbes are used. For example, large holes in Swiss cheese are due to CO2 produced by the bacterium Propionibacterium sharmanii. The BOD test measures the rate of uptake of oxygen by microorganisms in a sample of water and thus, indirectly, BOD is a measure of the organic matter present in the water. The greater the BOD of waste water, the more is its polluting potential. In anaerobic sludge digesters, bacteria produce a mixture of gases like methane, hydrogen sulphide and carbon dioxide. These gases form biogas and can be used as a source of energy. Biofertilisers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilisers are bacteria, fungi and cyanobacteria. You have studied about the nodules on the roots of leguminous plants formed by the symbiotic association of Rhizobium. These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as a nutrient. Other bacteria can fix atmospheric nitrogen while free-living in the soil (examples Azospirillum and Azotobacter).
BOD refers to the -

The electric charges are distributed in a small volume. The flux of the electric field through a sphere of radius 10 cm surrounding the total charge is 20 Vm. The flux over a concentric sphere of radius 20 cm will be:

The focal length of a thin lens in vacuum is f. If the material of the lens has refractive index \( \frac{3}{2} \), its focal length when immersed in water of refractive index \( \frac{4}{3} \) would be :