Q26 of 27 Page 1

(a) What is mutation breeding? Give an example of a crop and disease to which resistance was induced by mutation.

(b) Differentiate between pisciculture and aquaculture.


OR


a) If a patient is advised anti-retroviral drug, which infection is he suffering from? Name the causative organism.


b) How do vaccines prevent subsequent microbial infections?


c) How a cancerous cell differs from the normal cell?


d) Many microbial pathogens enter the gut of humans along with food. Name the physiological barrier that protects the body from such pathogens.


(a) Mutation breeding is the process by which mutations are induced artificially in plants by changing their base sequences or by using chemicals and radiations and selecting plants with desirable characters. Because of this, new characters are introduced in the plant which were absent in the parent plants.

Mung bean is resistant to yellow Mosaic Virus and Powdery Mildew.


(b)



OR


(a) If a patient is advised anti-retroviral drug, he is suffering from AIDS, which is Acquired Immuno Deficiency Syndrome. It is caused by HIV, which is Human Immuno Deficiency Virus.


(b) • The principle of vaccination is based on the ‘memory’ of the immune system.


• In vaccination, weakened or inactivated pathogens are introduced into the body.


• Because of this introduction, antibodies are produced in the body against these antigens which would neutralise the pathogenic agents that attack the person at the time of actual infection later.


• The vaccines also generate memory B and T cells which would recognise the pathogens upon subsequent infection by the pathogens by producing antibodies.


(c)


• Normal cells show a property called as Contact Inhibition due to which the normal cells remain in contact with the other cells thereby inhibiting their uncontrolled growth.


• But, this property is lost in cancerous cells.


• Because of the absence of this property, cancerous cells grow rapidly and divide uncontrollably, damaging the surrounding healthy cells as well.


• Cells which are damaged by tumours are carried by blood to different parts of the body and get lodged there starting a new tumour. This property as metastasis.


(d) The physiological barriers that protect the body from such pathogens are acid in the stomach and saliva in the mouth.


More from this chapter

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23

Large quantities of sewage is generated every day in cities and towns, which is treated in Sewage Treatment Plants (STPs) to make it less polluting. Given below is the flow diagram of one of the stages of STP. Observe the given flow diagram and answer the questions accordingly.


(a) Why primary effluent is passed into large aeration tanks?


(b) What is the scientific term used for the sediment formed? Mention its significance.


(c) Explain the final step resulting in the formation of biogas in the large tank before the treated effluent is released into water bodies.


 24


Observe the diagram of the catalytic converter and answer the questions which follow.


(a) Name any two metals used as catalyst in the catalytic converter.


(b) Name the gases released after passing the exhaust hydrocarbons through the catalytic converter.


(c) Which other poisonous gas is missing in the exhaust pollutant of an automobile in the above diagram?


 25

Certain phenotypes in human population are spread over a gradient and reflect the contribution of more than two genes. What is the term used for the types of inheritance? Describe it with the help of an example in human population.

OR


Summarize the process by which the sequence of DNA bases in Human Genome Project was determined using the method developed by Frederick Sanger. Name a free living non-pathogenic nematode who’s DNA has been sequenced.


 27

“Indiscriminate human activities have strengthened the greenhouse effect resulting in Global Warming.” Give the relative contribution of various Green House Gases in the form of a pie chart and explain the fate of the energy of sunlight reaching the earth’s surface contributing towards Global Warming.

OR


Given below is a table depicting population interactions between species A and species B.



Name the two types of population interactions (a) and (b) depicted in the above table. Justify giving three reason, how the type of interaction (b) is important in an ecological context.