Biology:2007:CBSE: [ Delhi ]:Set-I
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Q1
What happens to the glycogen concentration in the liver cells when the level of adrenaline increases in the blood stream of humans? Marks:1View AnswerAnswer:
Out of syllabus -
Q2
What is the importance of the epiglottis in human body? Marks:1View AnswerAnswer:
Epiglottis is a cartilaginous flap which prevents the entry of food in the glottis - the opening of wind pipe (trachea) during swallowing of food.
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Q3
Mention the scientific term used for modified form of reproduction in which seeds are formed without fusion of gametes. Marks:1View AnswerAnswer:
Apomixis -
Q4
What does ecological niche of an organism represent? Marks:1View AnswerAnswer:
The functional and positional status of an organism within an ecosystem is termed as ecological niche. -
Q5
It was diagnosed by a specialist that the immune system of the body of a patient has been suppressed. Name the disease the patient has been suffering from and its causative agent. Marks:1View AnswerAnswer:
AIDS.
HIV- III. -
Q6
Explain the significance of auxin/cytokinin ratio in plant tissue culture. Marks:2View AnswerAnswer:
Out of syllabus -
Q7
What does S-shaped pattern of population growth represent? How is J-shaped pattern different from it and why? Marks:2View AnswerAnswer:
S-shaped growth is a pattern of growth in which, in a new environment, the population density of an organism increases slowly initially, in a positive acceleration phase; then increases rapidly approaching an exponential growth rate but then declines in a negative acceleration phase until at zero growth rate the population stabilizes. Then, the growth of the population fluctuates at the carrying capacity.
J- shaped growth curve show only lag and exponential phase. -
Q8
What does secondary productivity in an ecosystem indicate? List any two factors by which productivity is limited in aquatic ecosystems. Marks:2View AnswerAnswer:
Secondary productivity is the rate of production of biomass by heterotrophs (animals), which feed on plant products or other heterotrophs.
Two factors which limit the productivity in aquatic ecosystems are light and temperature. -
Q9
How do viruses enter plant body and spread to long distances within it? Mention any two ways by which viruses spread from one plant to another. Marks:2View AnswerAnswer:
Viruses can enter the plant through the diseased part or diseased plant (entire plant). The two ways are: - Virus can enter through secondary host and wild plants. - They can also enter through diseased seeds and through soil absorbed. -
Q10
Where are casparian strips located in a plant body and what are they made up of? Mention its function. Marks:2View AnswerAnswer:
Out of syllabus
