How does photosynthesis work?

Learn how the process of photosynthesis works and understand its importance to our green environment.

Photosynthesis:

Imagine a planet with thin amounts of oxygen – in other words there would be no planet at all! All thanks to the process of photosynthesis which allows plants to convert light energy into usable food and remove carbon dioxide from the atmosphere and release oxygen into our environment. Without plants that perform photosynthesis, the oxygen on our planet would run out and all humans would choke in a carbon-dioxide rich atmosphere.


The Photosynthesis Reaction:

Light + 6CO2 + 12H20 --> C6H12O6 + 6O2 + 6H20


The Photosynthesis Process:
Photosynthesis in plants primarily occurs through its leaves, which are the solar collectors that begin the photosynthetic process. Leaves are covered with a waxy substance called a cuticle that allows them to retain water. Holes called stoma allow carbon dioxide to enter and oxygen to escape. Xylem cells inside the vein transport water from the roots to the leaves so photosynthesis can take place. Photosynthesis fundamentally requires carbon dioxide, which is obtained through tiny pores in plant leaves called stomata. Just like humans breathe through their lungs, plants breathe through their stomata. Oxygen is also released through the stomata and water is obtained by the plant through the roots and delivered to the leaves through vascular plant tissue systems. Sunlight is absorbed by chlorophyll, a green pigment located in plant cell structures called chloroplasts. Chloroplasts are the sites of photosynthesis.


Within the leaves are mesophyll cells which contain chloroplasts. Photosynthesis occurs within these structures, which contain a substance called chlorophyll. Chlorophyll, along with other pigments present in the chloroplast, absorbs the light energy of all colors but green for use in the photosynthesis process. The remaining green light is reflected back off of the plant, resulting in green color characteristic of a plant using photosynthesis for energy. Then hydrogen and oxygen are produced as by products of the process, by converting water using the energy derived from the sun. The hydrogen is combined with carbon dioxide in order to make food for the plant, whilst oxygen is let out by the plant through its stomates. Some of the light energy gathered by chlorophylls is stored in the form of ATP, or adenosine triphosphate, in order to be used in the next phase of photosynthesis.


During the final stage of photosynthesis, which is considered to be light-independent, carbon dioxide is converted into glucose. This chemical change requires the ATP that was stored in the first part of the photosynthesis cycle. This combination creates a compound called glyceraldehyde 3-phosphate, which combines with another glyceraldehyde 3-phosphate compound as it is produced, to produce one glucose molecule.


This wonderful process continuously happens during the day whilst we go about our everyday activities. If it weren’t for the process of photosynthesis, of what use would be all the precious solar energy that the sun provides us with?