Q22 of 44 Page 1

Expand ‘ELISA’ְ. Why is this method preferred over conventional methods of diagnosis of diseases ?

ELISA stands for Enzyme Linked Immuno-sorbent Assay.

ELISA is based on the principle of antigen-antibody interaction. Infection by a particular pathogen can be detected by the presence of antigens in the body or by detecting the antibodies synthesised against the antigen. This method is preferred over conventional methods of diagnosis of diseases because these tests are more accurate and are highly sensitive, specific as compared to other methods used for detection of antigens or antibodies.


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20

Draw a diagram of a typical agarose gel electrophoresis showing migration of undigested and digested sets of DNA fragments. Label (a) the digested and undigested DNA fragments, (b) Anode and cathode ends of the plate. Mention therole of electrophoresis in biotechnology.

 21

(a) Name a terminal method to prevent pregnancy in humans.

(b) Describe the procedure of the terminal method carried in human male and female.


OR


(a) Do all pollen grains remain viable for the same length of time? Support your answer with two suitable examples.


(b) How are pollen grains stored in pollen banks ? State the purpose of storing pollen grains in these banks.


 23

Waste Disposal and Waste Management poses a major problem in present times. Generation of garbage and its disposal is a major threat and consequently leads to severe environmental issues. The problem is not with biodegradable and recycled wastes. We realise that the need is to reduce non-biodegradable wastes.

(a) Why is there a great concern of managing non-biodegradable waste in comparison to biodegradable waste ? Explain.


(b) As a member of eco club of your school, suggest any two ways that you will discuss with your fellow members to organise for a “Zero garbage day” once in a month in the school.


 24

(a) Identify the parts labelled 1, 2 and 3 in the diagram given.


(b) Draw a labelled diagram of a human blastocyst.


(c) What is parturition and how is it induced at the end of pregnancy in a human female ?


OR


(a) With labelled diagrams, depict stages in embryo development in a dicotyledenous plant.



(b) Endosperm development precedes embryo development. Why ?