Photosynthesis (Cambridge International IGCSE Biology)

Spec point — 6.1.1 · Describe photosynthesis as the process by which plants synthesise carbohydrates from raw materials using energy from light

Photosynthesis

• Green plants make the carbohydrate glucose from the raw materials carbon dioxide and water
• At the same time oxygen is made and released as a waste product
• The reaction requires energy which is obtained by the pigment chlorophyll trapping light from the Sun
• So photosynthesis can be defined as the process by which plants manufacture carbohydrates from raw materials using energy from light

Exam Hint If asked for the raw materials required for photosynthesis, the answer is carbon dioxide and water.

Although required for the reaction to take place, light energy is not a substance and therefore cannot be a raw material.

Photosynthesis word equation

Spec point — 6.1.1 · State the word equation for photosynthesis as: carbon dioxide + water → glucose + oxygen in the presence of light and chlorophyll

• The photosynthesis word equation can be summarised as:

$carbon dioxide+water\rightarrow glucose+oxygen_{}$

• The reaction between carbon dioxide and water to form glucose and oxygen occurs in the presence of light and chlorophyll

The inputs, outputs, and requirements of photosynthesis.