A classical example of mutation arise due to change in a single base pair of DNA is:

Point out the technique, which is not useful for the detection of cancer of internal organs.

Match List-l with List-II

List-l (Scientists)	List-II (Discoveries)
(A) Frederick Griffith	(I) Genetic Code
(B) Francois Jacob and Jacque Monad	(II) Semi-conservative mode of DNA replication
(C) Har Gobind Khorana	(III) Transformation
(D) Meselson and Stahl	(IV) Lac operon

Choose the correct answer from the options given below:

Read the given paragraph carefully and answer the following questions:
Since the DNA is enclosed within the membranes, we have to break the cell open to release DNA along with other macromolecules such as RNA, proteins, polysaccharides and also lipids. This can be achieved by treating the bacterial cells/plant or animal tissue with enzymes such as lysozyme (bacteria), cellulase (plant cells), chitinase (fungus). There are some basic steps in genetically modifying an organism (i) identification of DNA with desirable genes; (ii) introduction of the identified DNA into the host; (iii) maintenance of introduced DNA in the host and transfer of the DNA to its progeny. Agrobacterium tumifaciens, a pathogen of several dicot plants is able to deliver a piece of DNA known as 'T-DNA' to transform normal plant cells into a tumor and direct these tumor cells to produce the chemicals required by the pathogen. Other molecules can be removed by appropriate treatments and purified DNA ultimately precipitates out after the addition of chilled ethanol. Selection of recombinants due to inactivation of antibiotics is a cumbersome procedure because it requires simultaneous plating on two plates having different antibiotics. Therefore, alternative selectable markers have been developed which differentiate recombinants from non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme, ß'-galactosidase. This results into inactivation of the gene for synthesis of this enzyme, which is referred to as insertional inactivation.
Agrobacterium tumefaciens, a pathogen of several dicot plants, is able to deliver a piece of DNA known as:

Match List - I with List - II.

List - I	List - II
(A) Plasmid of Salmonella	(I) Join foreign DNA to plasmid
(B) Restriction enzymes	(II) Insertional inactivation
(C) Ligases	(III) Construction of \(1^{s t}\) recombinant DNA
(D) \(\beta\)-galactosidase	(IV) Molecular scissors

Choose the correct answer from the options given below:

The first form of life could have come from pre-existing non-living chemicals by.

Which one of the following, is NOT an example of intra uterine contraceptive device?

A current I flows through an infinitely long, straight copper walled pipe. Then:

In the extraction of metallic Zn from calamine ore \(\left( ZnCO _3\right)\) following steps are involved :
(A) Distillation of impure Zn
(B) Calcination of the ore
(C) Hydraulic washing of ore
(D) Reduction of ZnO using coke
Choose the correct order of steps from the options given below :

The fluid filled cavity present in the secondary follicle is known as:

The gas which is used to produce and sustain powerful superconducting magnets, which form an essential part of Magnetic Resonance Imaging (MRI) system is :

Nitrogen containing compounds are basic in nature & their basic strength depends on ease of availability of lone pair of electrons on nitrogen atoms. For the following nitrogen containing compounds what will be correct order of basicity?

Choose the correct answer from the options given below :

A concave mirror of focal length 6 cm is placed at a distance 'd' from the convex lens of focal length 8 cm. A beam of light coming from infinity and falling on this convex lens-concave mirror combination returns to infinity. The distance 'd' must be equal to: