Long Answer Type(a) Name the technology that has helped scientists to propagate on a large scale the desired crops in a short duration. List the steps carried out to propagate the crops by the said technique.
(b) How are somatic hybrids obtained?
(a) Cancer is one of the most dreaded diseases. Explain 'Contact inhibition' and 'Metastasis' with respect to the disease.
(b) Name the group of genes that have been identified in normal cells that could lead to cancer. How do these genes cause cancer?
(c) Name any two techniques that are useful in detecting cancers of internal organs.
(d) Why are cancer patients often given I interferon as part of the treatment?
(a) Normal cells have the property of contact inhibition (stoppage of growth on coming in contact with other cells) but cancer cells lose this property. As a result, cancer cells divide continuously to give rise to a mass of cells (tumours). Metastasis- This property is exhibited by malignant tumours. It is the pathological process of spreading cancerous cells to the different parts of the body. These cells divide uncontrollably, forming a mass of cells called tumour. From the tumour, some cells get sloughed off and enter the blood stream. From the blood stream, these cells reach distant parts of the body and therefore, initiate the formation of new tumours by dividing actively.
(b) Cellular oncogenes (c-onc) or 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) Techniques such as radiography, CT (Computed Tomography) and MRI (Magnetic Resonance Imaging) are useful to detect cancers of internal organs.
(d) The biological response modifiers such as I interferon are given to cancer patients as part of their treatment because it activates a patient's immune system and helps in destroying the tumour.
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