Karnataka SSLC Question Paper 2022 Answer Key Science Biology

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KARNATAKA SECONDARY EDUCATION EXAMINATION BOARD, MALLESHWARAM,
BANGALORE – 560 003
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S. S. L. C. EXAMINATION, MARCH/APRIL, 2022

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MODEL ANSWERS
¶´¤MO⁄ : 11. 04. 2022 ] —⁄MOÊfi}⁄ —⁄MSÊ¿ : 83-E (Bio)
Date : 11. 04. 2022 ] CODE NO. : 83-E (Bio)

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Subject : SCIENCE
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( ffi»⁄À¤—⁄° / Biology )

( BMW«ŒÈ »⁄·¤®⁄¥¿»⁄fl / English Medium )

[ V⁄¬Œ⁄r @MO⁄V⁄◊⁄fl : 80
[ Max. Marks : 80

Qn.
Value Points Total

PART - C
( BIOLOGY )

XII. Multiple choice : 2×1=2

27. Atmospheric layer that absorbs ultraviolet radiations coming from the
sunlight is made up of this molecule.
(A) N 2 (B) H2
(C) O3 (D) O2 .

(C) O3
1

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83-E (Bio) 2 CCE RF & RR
Qn.
Value Points Total

28. In humans, sexually transmitted viral infection is
(A) AIDS (B) Syphilis
(C) Tuberculosis (D) Gonorrhoea.

(A) AIDS 1

XIII. Answer the following questions : 2×1=2

29. What is the role of decomposers in an ecosystem ?

Decompose dead wastes ( organic ) of plants and animals thus keep
surroundings clean and maintain ecological balance.
( Any other suitable answer ) 1

30. In males, testes are located outside the abdominal cavity in scrotum. Why ?

Because to maintain lower temperature required for the formation of sperms
than the normal body temperature. 1

XIV. Answer the following questions : 3×2=6

31. Mention the function of the following plant hormones :
i) Auxin

ii) Cytokinin.

i) Auxin :
Helps the cells in the stems and the cells in the many parts of the plant
body to grow longer. ( Any suitable answer ) 1
ii) Cytokinin :
Promotes cell division in fruits and seeds
Helps in promoting overall growth of plants. ( any one ) 1 2

32. Draw the diagram showing the longitudinal section of a flower and label
‘ovary’.
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CCE RF & RR 3 83-E (Bio)

Qn.
Value Points Total

Ovary

Longitudinal section of flower
Diagram — 1 1
2

Labelling — 1
2 2

33. Give reason :
a) ‘Ventricles of the human heart have thick wall.’
b) ‘It is necessary to separate oxygenated and deoxygenated blood in
mammals and birds.’

a) Since ventricles have to pump blood into various organs. 1
b) Since they need more energy to maintain their body temperature
constant. 1 2

XV. Answer the following questions : 3×3=9

34. When a tall ( TT ) pea plant is crossed with a dwarf ( tt ) pea plant, represent
the result obtained in F 2 generation of monohybrid cross with the help of

checker board and mention the ratio of varieties of plants.

Gametes T t

T TT Tt

t Tt tt 2

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83-E (Bio) 4 CCE RF & RR
Qn.
Value Points Total

Ratio

TT : Tt : tt

1:2:1 1

OR

Tall : Dwarf

3:1 3

35. What is trophic level ? Flow of energy in an ecosystem is always
unidirectional. Why ? Explain.

1
Different levels / stages of food chain.
2

1
Because,
2

The energy that is captured by autotrophs does not revert back to the
1
solar input.
2

The energy which passes to the herbivores do not come back to
1
autotrophs.
2

As energy moves progressively through the various trophic levels it is no
1
longer available to the previous level.
2
1
At different levels energy is lost in the form of heat.
2 3

36. a) Mention any four main factors that lead to the rise of new species.

b) The experiences of an individual acquired during its lifetime cannot be
passed on to its progeny. Give reason.

OR

What are fossils ? Mention the methods of estimation of dating fossils
and explain briefly.

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CCE RF & RR 5 83-E (Bio)

Qn.
Value Points Total

a) Factors responsible for the rise of new species :
Geographical isolation
Natural selection
Inheritance of traits
Genetic drift / gene flow
Variation / mutuation / changes in DNA.
( Any four ) 4× 1 =2
2

b) Change in non-reproductive tissues cannot be passed on to the DNA of
germ cells. 1 3
OR
Preserved traces of living organisms in deep layers of the earth. 1
Methods :
i) Relative method : The fossils we find closer to the surface are more
recent than fossils we find in deeper layers. 1
ii) Determining the time period by using isotopes ( dating )
Detecting the ratios of different isotopes of same element in the fossil
material. 1 3
XVI. Answer the following questions : 2×4=8
37. Which molecule is formed during the first step of cellular respiration by the
breakdown of glucose molecule in cytoplasm ? Mention the types of
respiration and write any two differences between them.
OR
Which are the factors essential for photosynthesis ? Mention the events that
occur during this process and represent this process by balanced chemical
equation.

Pyruvate. 1

Two types :
1
i) Aerobic respiration
2
1
ii) Anaerobic respiration.
2

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83-E (Bio) 6 CCE RF & RR
Qn.
Value Points Total

Aerobic respiration Anaerobic respiration

Atmospheric oxygen is utilised Atmospheric oxygen is not
utilised

Liberates more energy with Liberates less energy with
carbon dioxide and water ethanol and carbon dioxide

Takes place in mitochondria Takes place in cytoplasm

Takes place in higher levels of Takes place in lower
organisms organisms like yeast.

( Any two ) 1+1 4

OR

Factors essential for photosynthesis :

Carbon dioxide, water, minerals, sunlight and chlorophyll. 1

Events that occur during photosynthesis :
1
i) Absorption of light energy by chlorophyll.
2
1
ii) Conversion of light energy into chemical energy.
2
1
iii) Splitting of water molecules into hydrogen and oxygen molecules.
2
1
iv) Reduction of carbon dioxide into carbohydrates.
2

Equation :

Sunlight
6CO 2 + 12H 2 O    → C 6 H 12 O 6 + 6O 2 + 6H 2 O 1

Chlorophyll Glucose 4

38. Draw the diagram showing the structure of the human brain and label the
following parts :

i) Cerebrum

ii) Cerebellum.

RF/RR (A)-(200)-9046 (MA)-BIO

CCE RF & RR 7 83-E (Bio)

Qn.
Value Points Total

Cerebrum

Cerebellum

Human Brain

For diagram — 3
1 1
For labelling — +
2 2 4

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