ow would you test the presence of starch in leaves?
ve a brief description of the process of synthesis of food in green plants.
ow with the help of a sketch that plants are the ultimate source of
in the blanks:
since they synthesise
Green plants are called
their own food.
The food synthesised by plants is stored as
In photosynthesis solar energy is absorbed by the pigment called
and
During photosynthesis plants take in
elease
gas.
he following:
parasitic plant with yellow, slender and branched stem.
alant that is
rti
Answers
Answer:
Q1. The presence of starch in leaves can be tested using iodine Test. Procedure to test for the presence of starch in leaves:
Explanation:
1. Take a potted plant with variegated leaves-for example,money plant or crotons.
2. Keep the plant in a dark room for three days so that all the starch gets used up.
3. Now select a leaf cover its portion with a black strip paper and keep the plant in sunlight for about six hours.
4. Pluck the leaf from the plant. Mark the uncovered area in it and trace them on a sheet of paper.
5. Dip the leaf in boiling water for a few minutes. After this, immerse it in beaker containing alcohol.
6. Carefully place the above beaker in a water-bath and heat till the alcohol begins to boil.
7. Now dip the leaf in a dilute solution of iodine for a few minutes.
8. Take out the leaf and rinse off the iodine solution.
9. You observe that the presence of starch in various areas of the leaf which was uncovered.
Q2. Plants prepare Food themselves through the process of photosynthesis. Hence,they are called autotrophs. Leaves are the Food factories of plants. The synthesis of food occurs in their leaves. Therefore, all the raw materials such as water, carbon Dioxide and sunlight must reach there. Water and Minerals are transported to the leaves by the vessels which run like a pipes throughout the root,the stem,the branches and the leaves. The leaves have a green pigment called chlorophyll which helps leaves to capture the energy of sunlight. This energy is used to prepare food from carbon dioxide and water. This process of synthesizing food by the green plants is known as photosynthesis.
Q3. Fill in the blanks.
(i) Autotrophs
(ii) Starch
(iii) Chlorophyll
(iv) Carbon dioxide, Oxygen
Q4. Name the following.
(i) Cuscuta.
Answer:
(a) Green plants are called autotrophs since they synthesise their food.
(b) The food synthesised by plants is stored as starch.
(c) In photosynthesis, solar energy is absorbed by the pigment called chlorophyll.
(d) During photosynthesis, plants take in carbon dioxide and release oxygen gas.
Explanation: