Reactants used in light- dependent reactions : Carbon dioxide, sunlight and water.
- Through tiny holes in their leaves known as stomata, plants absorb carbon dioxide from the atmosphere. Most monocot plants have stomata on both surfaces of their leaves, while dicot plants and a few monocots only have stomata on the bottom epidermis of their leaves.
- Plants obtain water from the soil around their roots, and water travels via the xylem, a component of the plant's vascular system, to reach the leaves. The vascular bundle in leaves houses the xylem and phloem.
- The carbon dioxide and water molecules enter the leaf and then migrate into the cells of the mesophyll, the ground tissue layer that lies between the top and lower epidermis. These cells perform photosynthesis using water and carbon dioxide in organelles known as chloroplasts.
Reactants used in light- independent reactions : ATP, carbon dioxide, NADPH.
- The assembly of a glucose molecule is the final step in the light-independent processes, also known as the Calvin cycle. This stage of photosynthesis necessitates the CO2 that the plant absorbs from the atmosphere.
- In essence, the plant requires the carbon in the CO2 to make the components of glucose. RubP (ribulose biphosphate), a molecule with five carbons, and a molecule of carbon dioxide are combined by an enzyme called ruBisCo in the stroma. As a result, a six-carbon molecule is produced, which is then split into two three-carbon molecules (3-phosphoglycerate). The term "carbon fixation" refers to this phase of the light-independent processes.
- Then the light-dependent processes' energy carriers start to contribute. By adding a hydrogen atom to each 3-phosphoglycerate, ATP and NADPH produce two molecules of the simple sugar G3P. (glyceraldehyde-3-phosphate). In the end, one molecule of glucose is created from these two G3P molecules. Due to the addition of electrons, this phase of the light-independent processes is commonly referred to as reduction (or decreasing the sugar).