Leaves typically have a large surface area that contains chloroplasts to absorb sunlight for the process of photosynthesis. The chloroplasts contain a substance called chlorophyll. Chlorophyll is the substance that makes leaves appear green and allows them to absorb sunlight easily.
The structure of leaves allows them to aid in the process of photosynthesis because they are thin. This short distance between the front and back of a leaf allows carbon dioxide to disperse throughout it easily. The stomata are the part of the leaf that allows carbon dioxide to diffuse throughout it. They also contain guard cells that open and close the stomata under various conditions.
Leaves contain other pigments in addition to chlorophyll that allow them to absorb light from the sun's full spectrum. The veins in leaves, also called vascular bundles, provide support and transport water and carbohydrates to the plant. The outsides of leaves are covered by a thin epidermis that helps more light reach the palisade cells. Palisade cells are found in the top layer of leaves, and they house the chloroplasts. Their function is to allow as much sunlight as possible to absorb into the leaves.
A spongy layer that is filled with air pockets rests underneath the palisade cells. The spongy layer helps carbon dioxide diffuse from the stomata of the leaves and move into the cells that are responsible for photosynthesis.