Biology Sample Question Paper Sheet - Class Xii, Central Board Of Secondary Education, 2010 Page 31
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3915.
(i)
In which disease is there an uncontrolled division of cells resulting in formation of tumours?
How is this disease detected?
(ii)
How do interferons help in controlling the disease?
16.
State the principle underlying ‘gel electrophoresis’ and menttion two applications of this technique
in biotech-nology.
2
17.
You have developed a GM organism. Which government organisation will you approach to obtain
clearance for its mass production? Why is such a body necessary? Give two reasons.
2
18.
A person shows a strong immunogenic reactions while exposed
to certain substances. Name this
condition and common term for such substances. Mention the cell and its chemical which causes
this condition.
SECTION C
19.
Amazonian rain forest has the greatest biodiversity on earth. List any two hypotheses that are
proposed by the biologists to account for the greater biological diversity.
3
20.
(a)
In which part of the human female reproductive system do the following events take place?
st
I - Release of 1
polar body.
nd
II - Release of 2
polar body.
III - Fertilisation
IV - Implantation
(b)
From where do signals for parturition originate and what does maternal pituitary release for
stimulating uterine contractions for child birth?
3
21.
A true breeding tall plant is crossed with a true breeding dwarf plant. F
progeny is 100% tall and
1
F
has tall : dwarf in the ratio 3:1 (i) Explain why F
shows only one tpye of parental phenotype; (ii)
2
1
Name the patterns of inheritance in which the ratio deviates from above. Also mention the deviated
phenotypic ratio.
3
22.
In the following diagram the two DNA strands represented are ready for transcription
(4)
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