Download SCIENCE NOTES – STD 6 II TERM

SCIENCE NOTES – STD 6
II TERM - 2014
The Plant World
QI. Answer the following questions in brief:
1. What are the functions of roots in plants?
A. The root has the following functions:
a) It supports and holds the plant firmly to the ground.
b) It absorbs nutrients from the soil.
c) Some roots store food material. Such roots are known as storage roots. Eg: carrot, beetroot,
turnip and sweet potato.
d) Specialised roots as seen in some plants provide support to the plant. Eg: In banyan tree roots do
not arise from the radical, instead from the other parts of the plant. They are known as prop
roots.
2. Name the plant organ that stores food in the following cases:
a.
Turnip
Root
b. Ginger
c. Groundnut
Stem tuber
Stem tuber
3. Why are leaves modified into spines in the cactus plant?
A. Cactus plants grow in the desert region where there is scarcity of water. The leaves in this case turn
into spines to reduce loss of water during transpiration. The spines also protect such plants from
grazing animals.
4. What is transpiration?
A. Transpiration is the loss of water from the aerial parts of the plant in the form of water vapour.
5. Which is the reproductive unit of the plant? What are the specialised reproductive parts in it?
A. Flowers are the reproductive parts of the plant.
 Stamen is the male part of the flower and consists of the anther and the filament.
 Pistil/ Carpel is the female part of the flower and has the ovary, style and stigma.
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6. What is venation? Discuss the two types of venation in leaves.
Parallel venation
Reticulate venation
1.Veins run parallel to each other from the
petiole.
1.The leaf has a main vein running through
the centre that give rise to several small
veinlets.
2. Examples: grasses, cereals, banana
2. Examples: peepal, mango, hibiscus
7. Differentiate between Tap root System and Fibrous root system
Tap root system
Fibrous root system
1. A thick primary root grows vertically
downwards and gives off small lateral roots
1. Many roots arise as a tuft from the base
of the stem.
2. Eg: Rose, pea, dahlia, gram
2. Eg: Grass, maize, wheat, rice
QII. Answer the following questions in detail:
1. Draw a neat diagram of a flower and label the parts that: (You may use diagram A for reference and
label the parts in diagram B)
a. Attach the flower to the branch or stem
b. protect flower when young
c. are generally coloured
d. have anthers
e. possess style and stigma
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A.
B
2. What is photosynthesis?
A. Photosynthesis is the process by which green plants use carbon dioxide present in the air and water
and minerals from the soil to produce their own food in the presence of sunlight and chlorophyll.
3. Roots may not always perform the function of anchorage and absorption. Give examples to justify.
 In some plants such as carrot, beetroot, radish, turnip and sweet potato, the roots store food
material. Such roots are known as storage roots.
 Eg: In banyan tree, the roots are seen hanging from the branches. These specialised roots
provide support to the plant. They are known as prop roots.
4. Give reasons for the following:
a. Pitcher plant can make their own food, yet has an insectivorous habit.
Insectivorous plants like pitcher plant grow in regions where the soil is deficient in nitrogen. To make
up for this deficiency, they feed on insects.
b. Stems prepare food in most desert plants.
In desert plants like cactus, the leaves turn into spines to reduce water loss due to transpiration. The
stem in this case takes over the function of the leaf and performs photosynthesis.
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