Respiration in Organisms Class 7 Science Notes - Chapter 10

According to the CBSE Syllabus 2023-24, this chapter has been renumbered as Chapter 6.

Breathing vs. Respiration

Respiration

• Respiration is the process of gaseous exchange in an organism.
• Respiration at a cellular level, however, refers to the burning of food to obtain energy.

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Breathing

• Breathing is the process of taking in oxygen and giving out carbon dioxide by the organism.
• Every organism has its own methods of breathing.
• Every human breathes through the lungs.
• Organisms like,  fish breathes through the gills.

For more information on the Mechanism of Breathing, watch the below video

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Process of respiration

• The oxygen in the lungs is taken up by the blood.
• This oxygen is then transported to all parts of the body.
• Blood gives up oxygen to the cells and takes up carbon dioxide, which is sent back to the lungs.

Diffusion

• Diffusion is the process of movement of molecules from the area of their lower concentration to the area of their higher concentration without any application of energy.
• Diffusion is what happens when you put a drop of ink in water, and it slowly mixes with the water uniformly.
• The same principle is used for the exchange of gases (breathing) in animals.

Cellular respiration

• When the cells obtain oxygen from the blood, they use up this oxygen to burn the food.
• Burning of food releases energy which is stored in the form of ATP.
• Thus respiration at the cellular level is the burning of food using oxygen to get energy.

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Aerobic vs. Anaerobic

Aerobic respiration

The type of respiration in which organisms use oxygen for burning food inside the cell is called aerobic respiration.

Anaerobic respiration

Respiration in a cell in the absence of oxygen is called anaerobic respiration.

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How Do We Breathe?

Components of the respiratory system in Humans

The respiratory system of the humans have several parts; the Nasal chamber, pharynx, larynx, trachea, bronchi, lungs, and diaphragm.

The process of respiration in humans

• Respiration in humans starts with the breathing of air through the nose leading to the oxygen being transferred into the bloodstream by the lungs.
• This oxygen is delivered to all the cells, which uses them to burn glucose and generate energy.

Respiration in other organisms

• Respiration in other organisms is carried out by special organs.
• Frogs and earthworm use their moist skin, fishes use gills, and insects have spiracles.

Gaseous exchange in plants

• Gaseous exchange in plants occurs through stomata in leaves and through root hair in roots.
• The woody stems of plants have lenticels, too for the exchange of respiratory gases.