Page 72 - Science Class 07

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i Plants and different animals have different types of respiratory organs.
i Respiration takes place inside the cells of the body.
i During respiration, oxygen reaches the cells and combines with glucose (sugar) into which
food has been converted and energy is released.
i Man and most of the multicellular organisms carry out aerobic respiration.

i Micro-oganisms like yeast and a few bacteria carry out anaerobic respiration.
i Sugars are broken down by yeast, through anaerobic respiration, into alcohol in brewing
industries.
i Important organs involved in respiration in human beings are nostrils, trachea, pharynx,
larynx, bronchi, bronchioles, alveoli and lungs.

i Breathing is a mechanical process of taking in atmospheric air called inhalation and giving
out air which is called exhalation.

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A. Tick (3) the correct op on.
1. Which of the following is not a part of respira on in human beings?
(a) Glucose (b) Oxygen

(c) Water (d) Ammonia
2. Which of the following organisms does not need air for respira on?
(a) Earthworm (b) Fish

(c) Yeast (d) Frog
3. Which of the following is not a respiratory organ?
(a) Trachea (b) Bronchi
(c) Alveoli (d) Pancreas

4. Respiratory exchanges occur in:
(a) trachea (b) alveoli
(c) bronchi (d) lungs

5. The amount of _______________ is reduced from inhala on to exhala on.
(a) oxygen (b) carbon dioxide
(c) nitrogen (d) none of these
B. Fill in the blanks.
1. Respira on is a _______________ process in which food breaks down into simpler
substances and energy is released.

2. In _______________ respira on high amount of energy is released.
3. Larynx is connected with a muscular pipe, at its lower end, called _______________ .
4. _______________ is a flat muscle that provides as base for the lungs.

72 Science-7