Chloroplasts in Green Plant Cells. The most important part of photosynthesis occurs in the chloroplasts
Leaf mesophyll composed of parenchyma tissue.
The elongated palisade parenchyma contains the largest number of chloroplasts per cell and is the primary site of photosynthesis in many plants.
There are two main types of cells in a leaf:
the Palisade Mesophyll Cells then the spongy mesophyll cells.
The palisade mesophyll cells are packed tightly together towards the outer layer of the top and bottom of the leaf, and surround the spongy mesophyll cells which are less tightly packed together in order to allow for the buildup of water, oxygen, and carbon dioxide molecules between cells to create concentration gradients for different reasons (transpiration being the main reason in which the buildup of water molecules allows for the opening of the leaf’s stomata on the bottom layer of the leaf, or photosynthesis)
Most of the photosynthesis occurs in the palisade mesophyll cells, which contain more chloroplast. This would make sense since they are towards the outer layers of the leaf and therefore come into direct contact with sunlight, allowing for optimum levels of photosynthesis to occur assuming other factors allow for the optimum as well.