Gas Exchange

Gas exchange in plants takes place in the leaves. Gas exchange in plants is required for two critical processes.

1. Respiration
2. Photosynthesis

 

Respiration

Respiration is the release of energy from the breakdown of glucose in living cells. Respiration takes place in every living cell and all cells need to respire to produce the energy they need. Respiration involves the intake of oxygen and giving out of carbon dioxide. Respiration takes place all the time.

The equation for respiration is:

 

 

Photosynthesis

Photosynthesis is the process in which green plants produce glucose. It involves the conversion of carbon dioxide gas, water and minerals the plants take in from their surroundings into sugar and gaseous oxygen.

The equation for photosynthesis is given as:

 

Photosynthesis involves the intake of carbon dioxide and the release of oxygen. As it requires radiant energy it only takes place in the light.

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The table below summaries the two process involving gas exchange in green plants.

Process	Respiration	Photosynthesis
Gas In	Oxygen	Carbon Dioxide
Gas Out	Carbon dioxide, water vapour	Oxygen
Time	At all times – day and night	Requires sunlight – daytime only
Equation	glucose + oxygen carbon dioxide + water + energy	carbon dioxide + water glucose + oxygen

 

 

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