CHAPTER 4

PHOTOSYNTHESIS

B. Define the following:

1. Nutrition: The process of obtaining food and utilizing it for

various activities.

2. Photosynthesis: Plants make their own food with the help of

carbon dioxide taken in from the air and water from the soil, in

the presence of sunlight and a green pigment called chlorophyll

present in their leaves. This process is called photosynthesis.

3. Producer (Photosynthesizing organisms): Producers are any

kind of green plant. Most plants prepare their own food by the

process of photosynthesis and utilize the prepared food for various

activities.

4. Consumer: Any organism that can’t make its own food.

Consumers have to feed on producers or other consumers to

survive. E.g. Animals

C. Answer the following questions briefly.

1. Why is food needed by living organisms?

Ans: Every organism needs to take food to get energy and to perform

life processes. The living organism undergoes many life processes

like nutrition, respiration, digestion, transportation, excretion,

the circulation of blood, and also the reproduction. The energy to

the organism is mostly supplied through the food.

2. List the raw materials needed for photosynthesis

Ans: Carbon dioxide, water, sunlight and chlorophyll

3. What does stomata help in?

Ans: Stomata regulate the loss of water and exchange of gases (such

as CO2 and O2) by opening and closing.

4. Write down the word equation for the process of photosynthesis.

Ans: Sunlight

Carbon dioxide + Water Glucose+ Water + Oxygen

Chlorophyll

III. Long answer questions

A. Differentiate between the following:

2. Producer and consumer

Producer (Photosynthesizing organisms): Producers are any kind of green

plant. Most plants prepare their own food by the process of photosynthesis

and utilize the prepared food for various activities.

Consumer: Any organism that can’t make its own food. Consumers have to

feed on producers or other consumers to survive. E.g. Animals

1. Autotrophic and heterotrophic nutrition

B. Answer the following questions in detail.

1.

2.

3. Discuss the factors that affect the rate of photosynthesis.

4. With the help of a neat diagram explain the structure of chloroplast

5. With the help of a neat and labelled diagram explain the mechanism of opening and closing of stomata.