DAV Class– 7 Science Book Solutions Chapter-1 Nutrition in Living Organisms-Plants

DAV class 7 Science chapter 1 Question Answer: Are you looking for DAV Books Solutions then you are in right place, we have discussed the complete solution of Science class 7 Chapter 1 Nutrition in Living Organisms. DAV class 7 Science chapter 1 question answer is given below.

DAV Class- 7 Nutrition in Living Organisms Question and Answer

Something To Know

A. Fill in the blanks.

1. Animals are ___________ as they cannot synthesis their own food.

2. The ___________, of a plant, absorb water and minerals from the soil.

3. During photosynthesis plants take in ___________ and release ___________.

4. ___________ are the tiny pores through which leaves exchange gases.

5. Insect eating plants are called ___________ plants.

6. An essential raw material needed for the process of photosynthesis, and

(a) available in the soil is ___________.

(b) available in the air is ___________.

Answer: (1) Heterotrophs (2) roots (3) Carbon dioxide, Oxygen (4) Stomata (5) insectivorous (6) (a) water (b) Carbon dioxide

B. Match the following:

C. Tick the correct option.

1. Green plants, that can synthesise their own food, are known as—

Ans 1: Autotrophs

2. The food factory, of the plant, is its—

Ans 2: Leaf

3. Which of the following is an insectivorous plant?

Ans 3: Pitcher plant

4. Mushroom is an example of a/an—

Ans 4: Saprotroph

5. An organism, that fixes nitrogen in the soil, is—

Ans 5: Rhizobium

D. Answer the following questions in brief.

1. Why is nutrition important for a living organism?

Ans 1: Nutrition is important for a living organism because we need nutrition for growth, repairing damaged parts of our body, resistance to fight against diseases, and providing energy to carry out day-to-day activities.

2. How do green plants synthesise their food?

Ans 2: Green plants synthesize their own food by the process of photosynthesis. 

3. State the role of ‘vessels’ present in a plant.

Ans 3: Vessels help in the transportation of water and minerals to other parts of the plant.

4. Define the following terms:

(a) Symbiotic relationship

Ans 4(a): Sometimes two organisms live in close association and develop a relationship that is beneficial to both. This is called a symbiotic relationship.

(b) Nutrients

Ans 4(b): Nutrients are nutritional components such as carbohydrates, proteins, lipids, vitamins, and minerals that promote growth, provide energy and maintain life

(c) Saprotrophic mode of nutrition

Ans 4(c): Saprotrophic nutrition is the process in which the organisms feed on dead and decaying matter.

(d) Photosynthesis

Ans 4(d): The process through which green plants prepare their own food is called photosynthesis.

5. When some wheat dough was left in the open for a few days, it started emitting a foul smell. State, why?

Ans 5: When the wheat dough is left open for a few days it starts emitting a foul smell due to the action of fungi and bacteria that grow on it. These organisms are called Saprotrophs which obtain food from dead and decaying organic matter.

E. Answer the following questions.

1. Why would life not be possible on the earth in the absence of photosynthesis?

Ans 1: Photosynthesis is the process through which plants produce their food. In absence of photosynthesis, there would be no plants, and oxygen gas, which is required for respiration. All animals are dependent on plants for food directly or indirectly therefore in absence of photosynthesis life would not be possible on the earth.

2. Give reasons for the following:

(a) Mushroom is a saprotroph.

Ans 2(a): Mushroom does not contain chlorophyll therefore it does not make its own food by photosynthesis. Mushrooms are considered to be saprotrophs as they grow on dead and decaying matter and obtain nourishment from it by secreting digestive juices. The organisms which exhibit a saprotrophic mode of nutrition are called as saprotrophs.

(b) Sun is the ultimate source of energy for all living organisms.

Ans 2(b): The sun is called the ultimate source of energy because plants convert light energy from the sun into chemical energy (food) by the process of photosynthesis. Animals eat plants and use that same chemical energy for all their activities.

(c) The leaf of a plant ‘dies out’ if its stomata are blocked.

Ans 2(c): Stomata help in photosynthesis by exchanging the gases like oxygen and Carbon dioxide. If the stomata of a leaf are blocked, it does not make their food and the leaf dies out.

(d) Leaf is known as the food factory of the plant.

Ans 2(d): The leaf of a plant synthesizes its food by the process of photosynthesis. Hence, it is known as the food factory of the plant.

(e) Lichen is a ‘living partnership’ between a fungus and an alga and this partnership is beneficial to both.

Ans 2(e):  Lichen is a living partnership between a fungus and alga because the alga present in the relationship produces food whereas the fungus present in the relationship provides shelter to the entire group.

3. Why do some plants feed on insects? How does a pitcher plant catch insects?

Ans 3: Insectivorous plants trap insects because they grow in soil that is usually thin and is also poor in nutrients, so they eat insects to fulfil their nutrient requirement. The pitcher plant is an example of this type of plant. The leaf of this plant gets modified to form a pitcher with a lid. The lid is able to open and close the mouth of the pitcher. The pitcher is lined with downward-pointing hairs. When an insect enters, it cannot climb back out against the hairs and ultimately falls to the bottom of the leaf, and gets digested by the juices present there.

4. How do rhizobium bacteria and leguminous plants help each other in their survival?

Ans 4: Rhizobium is a bacterium that lives in the roots of leguminous plants. It converts nitrogen, from the atmosphere, into a usable form that can be utilized by the plants. The plants, in turn, provide food and shelter to the bacterium.

5. Complete the web chart.

Ans 5: