(a) Name the technology that has helped the scientists to propagate on large scale the desired crops in short duration. List the steps carried out to propagate the crops by the said technique.

(b) How are somatic hybrids obtained ?

OR

(a) Cancer is one of the most dreaded diseases of humans. Explain 'Contact inhibition' and 'Metastasis' with respect to the disease.

(b) Name the group of genes which have been identified in normal cells that could lead to cancer and how they do so ?

(c) Name any two techniques which are useful to detect cancers of internal organs.

(d) Why are cancer patients often given α-interferon as part of the treatment ?

a) With the help of tissue culture we propagate desired crop in short duration with the help of following steps:

• Preparation of suitable nutrient medium- this step is performed in lab under sterile condition which contain required nutrients.

• Selection of explant- explants are any excised part of the plant to be used in tissue culture like buts, root tip, shoot tip anther, ovary etc.

• Sterilization of explant- explants are sterilized by using different types of disinfectants like sodium hypochlorite etc.

• Inoculation of explant- the sterile explants is inoculoated on the surface of the solidified nutrient medium under aseptic condition.

• Incubation- incubation is done under required temp, humidity, light etc.

• Transfer of callus and regeneration- the callus obtained from incubation of explants is transferred into another medium and reincubated.

• Transfer of plantlets to the field- plantlets are transferred to either the green house or the field condition outside. Transfer of callus and regeneration- the callus obtained from incubation of explants is transferred into another medium and reincubated.

• Transfer of plantlets to the field- plantlets are transferred to either the green house or the field condition outside.

b). Somatic hybrids are produced with the help of somatic hybridization in which two somatic cells of two different plants are fused.

Protoplasts of two plants are isolated and form a hybrid plant.

For eg. With the help of this technique we produce potamato which is a fusion of potato and tomato.

OR

a). Uncontrolled cell division is called cancer.

Cancer cell lose the property of contact inhibition that is stoppage of growth on coming in contact with other cells, as a result they give rise a mass of cells.

Metastasis is found in malignant tumours. It is a pathological process of spreading cancer cells to other parts of body through the blood stream they reach distant parts of the body and initiate new tumour.

b). Cellular oncogenes and proto oncogenes are the group of genes that have been identified in normal cells. These genes when activated under certain conditions, could lead to oncogenic transformation of the cells.

c). Doctors use some techniques to detect cancer cells are- MRI( Magnitic Resonance Imaging), CT( Computed Tomography) and Radiography are useful to detect cancers of internal organs.

d). α-interferons are biological response modifier which is given to cancer patients for their treatment because it help in immune system activation and destroying the tumour cells.