NUTRITION IN PLANTS

1. What is nutrition?

Ans The mode of taking food by an organism and its utilisation by the body.

2. Differentiate between autotrophic nutrition and heterotrophic nutrition.

Ans 1.The mode of nutrition in which organisms make food themselves from simple substances is called autotrophic nutrition.
2. The mode of nutrition in which organisms depend on other organisms for their food is called heterotrophic nutrition.

3. What are nutrients?
Ans The components of food that are necessary for our body are called nutrients. Carbohydrates, proteins, fats, vitamins and minerals are components of food.

4. What are the raw materials needed for photosynthesis?
Ans Sunlight, Carbon dioxide,  water and chlorophyll.

5. What is photosynthesis?
Ans The process by which green plants make their own food in the presence of sunlight using carbon dioxide and water with the help of chlorophyll is called photosynthesis. Carbohydrate and oxygen is formed. This process can be represented as an equation-

6. Explain photosynthesis with the help of diagram.

Ans 1. Carbon dioxide- It is obtained from air through tiny pores present underneath the leaves called stomata. Stomata is surrounded by guard cells which help in closing and opening the stomata.

2. Water- Water and minerals are absorbed by the roots of the plant and are transported to the leaves by the tubes in the stem(XYLEM).

3.Chlorophyll- Chlorophyll is a green pigment present in the leaf(FOOD FACTORY) which helps to trap sunlight.

4. Sunlight- Solar energy is used for the chemical reaction between carbon dioxide and water. The solar energy is converted to chemical energy in the process of photosynthesis. leaves store their food in the form of starch.

7. Describe the structure of a cell with the help of a diagram.

Ans 1. The bodies of living organisms are made up of tiny units called cells. The cell is enclosed by a thin outer boundary called cell membrane.

2. Most cells have a distinct centrally located spherical structure called the nucleus.

3. The nucleus is surrounded by a jelly like substance called cytoplasm.

8. What are variegated leaves? Give examples.  

Ans  Plants which have got pigments other than chlorophyll in large quantities are called variegated leaf plants. The colour pigments mask the chlorophyll present, hence they don't appear green. Still they take part in photosynthesis. Eg Croton, Coleus, etc

COLEUS

CROTON

9. What are algae? Is it an autotroph?

Ans Algae are slimy green patches in ponds or in other stagnant water bodies. They contain chlorophyll which gives them green colour and they prepare their own food by photosynthesis, hence they are autotrophs.

10. How do plants obtain nitrogen?

Ans 1.Soil has certain bacteria that convert gaseous nitrogen into a usable form and release it into the soil. These soluble form are absorbed by the plants along with water.

2. Farmers add fertilizers rich in nitrogen to fulfill the requirements of plants.

11. Define the following-

1. Parasites-Organisms that live in/on other organisms and derive readymade food from the host are called parasites. eg Cuscuta/Amarbel

2. Saprotrophs- Organisms which take food from dead or decaying matter are called saprotrophs. eg mushroom, fungus 

3. Symbiosis- The mode of relation in which two organisms live together for mutual benefit is called symbiosis. eg In organisms called Lichens, chlorophyll containing partner, which is an alga and a fungus live together. The fungus provides shelter, water and minerals to the alga and in return the alga provides food which it prepares by photosynthesis.

12. Explain the mode of nutrition in pitcher plants.

Ans The pitcher-like structure is the modified part of the leaf. The apex of the leaf forms a lid which can open and close the mouth of the pitcher there are hair which are directed downwards. When an insect lands in the pitcher. The lid closes and the trapped insect gets entangle into the hair. The insect is digested by the digestive juices secreted in the pitcher.

13. How does a saprotroph digest its food?

Ans Saprotrophs secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it.

14. How is the symbiotic association between Rhizobium and Leguminous plants beneficial?

Ans Plants cannot take nitrogen in gaseous form. A bacteria called Rhizobium which is present in the root nodules of leguminous plants fixes it as it can convert gaseous nitrogen into a soluble form. This soluble nitrogen is taken by the leguminous plants and in return give food and shelter to the bacteria.