B8 Photosynthesis

B8 Photosynthesis

B8.1

Energy is transferred from the environment to chloroplasts by light, which is then transferred to convert the air's carbon dioxide and water from the soil to make glucose. Oxygen is produced as a product. It is an endothermic reaction - it needs energy from the environment and more energy is released when bonds are broken than when formed.

carbon dioxide + water -> glucose + oxygen

6CO2 + H2O -> C6H12O6 + 6O2

Glucose is used for respiration and starch conversion.

Leaves are adapted for photosynthesis:

• have a large surface area to catch light to fall on
• short diffusion distances for gases
• chlorophyll absorbs light
• veins bring water and remove products of photosynthesis
• have air spaces allowing carbon dioxide in and oxygen out
• guard cells regulate gas exchange.

B8.2

Light, warmth, and carbon dioxide are limiting factors because if any one of them are in short supply, they limit photosynthesis. If there is a lot of light or bright light, there is more or faster photosynthesis. Carbon dioxide is a limiting factor on sunny days since there is less concentration of it. Once temperature rises to 40-50 degrees C, enzymes become denatured and photosynthesis falls. Also, the amount of chlorophyll and minerals limit the plant too.

Light intensity and light distance are inversely proportional.

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