Photosynthesis is one of the most widely studied phenomena in science. Nobel prizes have been awarded and universities around the globe have teams studying how it works, and what its byproducts are.
Chlorophyll
Just like the old question of whether the chicken or the egg came first, the same could be said about chlorophyll. In the early days of this planet's existence, almost all of the land areas were covered with dense ferns, which of course contained chlorophyll. All of that greenery released tremendous amounts of oxygen, as well as creating massive layers of decaying plants, which would release the carbon stored in them.
How does photosynthesis work?
There are several types of photosynthesis that occurs in both terrestrial and aquatic plants, algae and some bacteria. The key to photosynthesis is sunlight. The chlorophyll in a plant's leafs, and to a very minor extent the stems, reacts to sunlight by producing a chemical energy to create carbohydrates which are stored in the plant's molecules.
What takes place is that carbon dioxide created by organic matter breaking down, plus water absorbed by the roots of the plant and sunlight in a suitable spectrum, from violet to infrared, or from 400 nanometers to about 1,000 nm, work together to bring about the growth of plants.
When photosynthesis occurs, a plant will start producing glucose and oxygen. Enzymes and chlorophyll are also produced during the process.
The water the plant takes in is held in cells, which, via osmosis, diffusion and other transport mechanisms through their semipermeable membranes, will allow good products to enter while blocking undesirable substances. Keep in mind that all this takes place on a microscopic level!
Elements of a plant cell
A single plant cell is a very complicated unit consisting of at least six different elements:
The same process is responsible for our produce and fruits, taking the glucose from the leaves to create edible foods for virtually all creatures.
This delicate balance is easily upset, if a plant is deprived of direct sunlight by other plants that shade it. Kudzu is a plant that will take over and starve anything in its way, as will pine and eucalyptus trees. Their rapid growth and height combine to deprive many hardwood species of the necessary light they need to grow, leaving them stunted and unable to reproduce.
What substances does photosynthesis produce?
The answer to the question of just what photosynthesis produces is the oxygen in the air you breathe and the glucose in the food you eat. Without photosynthesis, neither would exist.