Figure 1
Introduction Photosynthesis, the process by which most plants and trees produce carbohydrates, has both light reactions, which need light in order to occur and dark reactions which are independent of light. During these dark reactions CO2 is broken down, or fixed and used to create carbohydrates. The main source for the CO2 consumed in photosynthesis is the atmosphere, consisting of about 0.03% CO 2. Dissolution of CO2 in water leads to the following reaction: (1)
H2 O + CO2 ⇌ H2 CO3 ⇌ HCO3− + H +
The bicarbonate ions produced in this reaction serve as a source of CO2 for the dark reactions of photosynthesis.