Biology:2007:CBSE:[ Delhi ]:Set-III
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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
What is the importance of mucous cells in the human digestive tract? Marks:1View AnswerAnswer:
Mucous cells in the human digestive tract forms a protective layer to prevent the possible damage caused to stomach cells by the acid and they also secrete mucus rich secretion that helps in lubrication. -
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 is the action potential in an axon of a neuron? Do all neurons possess the same action potential? Give a reason Marks:2View AnswerAnswer:
Out of syllabus -
Q9
What is gynaecomastia? What is its cause during neonatal period and during puberty? Marks:2View AnswerAnswer:
Out of syllabus -
Q10
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.
