The function of leaves is to help the plant produce food by converting the energy in sunlight into chemical energy that the plant can eat. The structures within the leaf convert the energy and make it possible for the plant to get food.
Chlorophyll is the molecule in the structure of the leaves that takes the energy in sunlight to turn water and carbon dioxide gas into sugar and oxygen gas. This conversion process is known as photosynthesis.
Leaves are made out of several layers that are in between two layers of super tough skin cells called epidermis. The epidermis is also known to secrete cuticle, which is a waxy substance. All of these layers protect the leaf from pests such as insects and bacteria. There are also stomata cells that are pores where gases can enter and exit through the leaf.
Most of the food production in the leaf actually takes place in the elongated cells that are known as palisade mesophyll inside the leaf. The leaf also has veins that can help to support the leaf by transporting food, water and minerals to the leaf and to the plant.
Leaves are also important for humans as they are one of the best ways to identify various plants. Leaves come in many shapes and sizes, such as flat, wide, spiky, thin, rectangular and oval.