Important Questions for Class 7 Chapter 10 - Respiration in Organisms

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Important questions based on NCERT syllabus for Chapter 10 - Respiration in Organisms:

Question-1: Anil was a participant of Marathon-14. After the race he got muscle cramps. Why do you think he got muscle Cramps and how can he recover from that?

Solution: Muscle cramps occur when muscle cells respire anaerobically. Glucose in muscle cells produce lactic acid during anaerobic respiration and accumulation of lactic acid causes muscle cramps. By massage or using hot water he can recover from muscle cramps as these improve blood circulation. Thus supply of oxygen to muscle
cells increases and complete the breakdown of lactic acid into carbon dioxide and water occurs.

Question-2: How do plants respire?

Solution: In a plant the roots take air present in the soil. Leaves have tiny pores called stomata through which they exchange gases.Respiration uses oxygen and produces carbon dioxide. In plant cells the breakdown of glucose in presence of oxygen gives water and carbon dioxide like other organisms.

Question-3: Explain how do we breathe?

Solution: We take in air through our nostrils. When we inhale, air passes through nostrils into nasal cavity which reaches the lungs through windpipes. The chest cavity where the lungs are present is surrounded by ribs on the sides and diaphragm forms the base .Breathing involves the movement of the diaphragm and the rib cage.
During inhalation, ribs move up and diaphragm moves down to increase the chest cavity space. Lungs get filled with air.During exhalation, ribs move down and diaphragm moves up to its former position. Thus reduces chest cavity space and air is pushed out.