Photosynthesis and Plants Photosynthesis Process by which plants

Photosynthesis and Plants

Photosynthesis Process by which plants and other photosynthetic organisms produce food in the form of glucose. Light energy Carbon dioxide + water Chlorophyll Glucose + Oxygen

Chlorophyll ● Makes plants green! ● Found in the chloroplasts. ● Absorbs light energy from the Sun for photosynthesis.

Photosynthesis - need to know! ● Most photosynthesis takes place in the leaves of a plant. ● Photosynthesis can only take place during the day - when there is Sunlight. ● Enzymes control photosynthesis - so changes in temperature affect the rate of photosynthesis.

Three factors which affect the rate of photosynthesis ● Temperature ● Concentration of Carbon dioxide in the air. ● Light intensity

Temperature ● Increasing temperature will increase the rate of reaction up to the optimum temperature. ● The rate of photosynthesis will slowly go down when the temperature goes above the optimum temperature. ● This is because enzymes control photosynthesis!

Carbon dioxide concentration ● Increasing the concentration of carbon dioxide will initially increase the rate of photosynthesis. ● This is because there is more carbon dioxide available to react with water during photosynthesis. ● The rate of photosynthesis will level off eventually though.

Carbon dioxide concentration

Light intensity

Light intensity ● Increasing the light intensity will initially increase the rate of photosynthesis. ● This is because there is more light energy available for photosynthesis to take place. ● The rate of photosynthesis will eventually level off.

Uses of glucose produced during photosynthesis ● Used in respiration to release energy for chemical reactions. ● Used to make proteins, oils and cellulose. ● Forms starch (a long chain of glucose molecules) for storage. ● Starch is a store of chemical energy for when the plant cannot photosynthesise e. g. night time, winter.

Storage of starch ● Starch is stored in various places in the plant: - Starch granules found in plant cells. - In tubers e. g. potatoes - In fruits. - In seeds or grains.