Exercise
1. Why do organisms take food?
2. Distinguish between a parasite and a saprotroph.
3. How would you test the presence of starch in leaves?
4. Give a brief description of the process of synthesis of food in green plants.
5. Show with the help of a sketch that plants are the ultimate source of
food.
Answers
Question 1:
Why do organisms need to take food?
Answer:
All organisms need to take food to get energy for the growth, development, locomotion and maintenance of their bodies.
Question 2: Distinguish between a parasite and a saprotroph.
Answer:
Difference between a parasite and a saprotroph
s.No
Parasite
Saprotroph
1.
Organisms derive nutrition from the body of other living organisms (host) are parasites.
Plants which derive nutrition from dead and decaying organisms are called saprotrophs.
2.
Example: Cuscata
Example: Mushrooms
Question 3: How would you test the presence of starch in leaves?
Answer:
Take a potted plant with variegated leaves – for example, money plant or crotons.
Keep the plant in a dark room for three days so that all the starch gets used up.
Now select a leaf cover its portion with a black strip paper and keep the plant in sunlight for about six hours.
Pluck the leaf from the plant. Mark the uncovered area in it and trace them on a sheet of paper.
Dip the leaf in boiling water for a few minutes.
After this, immerse it in a beaker containing alcohol.
Carefully place the above beaker in a water-bath and heat till the alcohol begins to boil.
Now dip the leaf in a dilute solution of iodine for a few minutes.
Take out the leaf and rinse off the iodine solution.
You observe that the presence of starch in various areas of the leaf which was uncovered.
Question 4:
Give a brief description of the process of synthesis of food in green plants.
Answer:
Leaves are the food factories of plants. The synthesis of food in plants occurs in leaves.
Therefore, all the raw materials (Water, Carbon dioxide and sunlight) must reach there.
Water and minerals are transported to the leaves by the vessels which run like 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 the sunlight.
This energy is used to synthesise (prepare) food from carbon dioxide and water. This process is termed as ‘Photosynthesis’.
Question 5:
Show with the help of a sketch that the plants are the ultimate source of food.
Answer:
All the living being depends on plants whether directly or indirectly.
For example, the plant eater animals depend directly on plants but carnivore depends indirectly on plants.
The following sketch shows some examples of plant dependency.
Mark me as brainliest!!!
Answer:
ans.1.- Organisms eat food because they need energy to all the works that they do in their daily life and also they take food because they need immunity to be healthy.
Ans.2.- I don't know sorry
Ans.3.- To test the presence of starch in leaf you will need a dropper, iodine solution in liquid form and a leaf.
First take a leaf and put a drop of iodine solution on it if the leaf turns blue-black in colour it means that it contains starch.
Ans.3.- Sorry i don't know.
Ans.4- Sorry i don't know