NCERT Class 7 Science – Chapter 1: Nutrition in Plants and Animals QA

By dk - April 03, 2025

NCERT Class 7 Science – Chapter 1: Nutrition in Plants and Animals

Chapter Summary:

This chapter explains different types of nutrition. Plants prepare their own food through photosynthesis, making them autotrophic. They use sunlight, water, and carbon dioxide to produce glucose and oxygen.

Some organisms, like fungi, Cuscuta (Amarbel), and certain bacteria, depend on others for food and are called heterotrophic. The chapter discusses different types of heterotrophic nutrition:

Parasitic nutrition: Organisms depend on a host for food (e.g., Cuscuta).
Saprotrophic nutrition: Organisms obtain food from dead and decaying matter (e.g., fungi).
Symbiotic nutrition: Two organisms benefit from each other (e.g., Lichen – a combination of algae and fungi).

The chapter also explains how Amoeba captures and digests food using pseudopodia (false feet). It highlights the importance of nutrition in all living beings.

Question-Answers:

1. Fill in the Blanks:

(a) During photosynthesis, plants take in ________ gas and release ________ gas.
Answer: Carbon dioxide, Oxygen

(b) Amoeba uses ________ to capture food.
Answer: Pseudopodia

(d) Fungi obtain food through ________ mode of nutrition.
Answer: Saprotrophic

(e) The green pigment essential for photosynthesis is called ________.
Answer: Chlorophyll

2. Match the Following:

Answer:
(a) → (i), (b) → (ii), (c) → (iii), (d) → (iv), (e) → (v)

3. True/False Statements:

(a) The process by which plants prepare food is called photosynthesis.
Answer: True

(b) Fungi prepare their own food.
Answer: False

(d) Lichen is an example of a symbiotic relationship.
Answer: True

(e) Chlorophyll gives green color to leaves.
Answer: True

4. Short Answer Questions:

(a) What is photosynthesis?
Answer: Photosynthesis is the process by which green plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. It occurs in the leaves with the help of chlorophyll.

(b) What is saprotrophic nutrition?
Answer: Saprotrophic nutrition is a mode of nutrition in which organisms obtain food from dead and decaying organic matter. Example: Fungi and bacteria.

(c) What is the difference between parasitic and symbiotic nutrition?
Answer: Parasitic nutrition involves one organism depending on another for food, harming the host (e.g., Cuscuta). In symbiotic nutrition, two organisms help each other (e.g., Lichen).

(d) How does Amoeba obtain food?
Answer: Amoeba captures food using its pseudopodia (false feet), surrounds it, and digests it inside a food vacuole.

(e) What is Lichen?
Answer: Lichen is a symbiotic association between algae and fungi, where algae provide food through photosynthesis, and fungi offer protection and water.

5. Long Answer Questions:

(a) Explain the process of photosynthesis in plants.
Answer:
Photosynthesis is a biological process where green plants use sunlight to convert carbon dioxide and water into glucose and oxygen. It occurs in the chlorophyll-containing leaves. The chemical equation is:


6CO_2 + 6H_2O + \text{Sunlight} \rightarrow C_6H_{12}O_6 + 6O_2

(b) Differentiate between parasitic and saprotrophic nutrition.

(c) How does Amoeba capture and digest food?
Answer:
Amoeba is a unicellular organism that uses pseudopodia (false feet) to capture food. When it detects food, it extends its pseudopodia around the food particle and engulfs it, forming a food vacuole. Inside the vacuole, digestive enzymes break down the food, and the nutrients are absorbed. The undigested waste is expelled out of the body. This process is known as phagocytosis.

Conclusion:

This chapter teaches us that plants prepare their own food through photosynthesis, while animals and fungi depend on other sources. Different types of nutrition exist in nature, such as autotrophic, parasitic, saprotrophic, and symbiotic nutrition. Understanding these concepts helps us appreciate the importance of nutrition in all living beings.

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