Plant Processes: Gas Exchange and Photosynthesis
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Transcript of Plant Processes: Gas Exchange and Photosynthesis
Plant Processes: Gas Exchange and Photosynthesis
What is gas exchange in plants?• When we inhale, we breathe in a mixture of gases we
need for survival• When we exhale, we breathe out the waste products• In plants, CO₂ and H₂O are two substances needed for
survival– CO₂ enters through the stomata – H₂O is absorbed through roots of
the plant and released as water vapor through the stomata
Gas Exchange• Light, H₂O and CO₂ all
affect the opening and closing of stomata
• Stomata are usually open during the day and close at night – When stomata closes, less
CO₂ can enter and less H₂O can escape
• When plants lose water vapor through stomata, this is called transpiration
Photosynthesis
• Photosynthesis is the process inwhich plants use light energy to make food– Chlorophyll is a chemical in plants that helps to
capture this light energy• Other than light, plants also need H₂O and CO₂• These molecules combine to form an organic
compound, a carbohydrate (sugar) called glucose
Process of Photosynthesis
6CO₂ + 6H₂O + light energy C₆H₁₂O₆ + 6O₂ Carbon dioxide + water + light (and chlorophyll) produces glucose and oxygen
• A plant needs 6 molecules of carbon dioxide (CO₂) and 6 molecules of water (H₂O) to make one molecule of glucose (C₆H₁₂O₆)
• The chemical bonds in glucose contain the energy the plant needs for growth and survival and is the main source of food for plants
• Oxygen is produced as a waste product during photosynthesis and released through plant stomata