Photosynthesis is the process whereby a plant manufactures food from sunlight, carbon dioxide and water. The word means ‘light making’ or’ making from light ‘ and it is important because plants are the first organisms in a long food chain to capture the energy from the sunlight striking our planet and it is this energy which is transferred all the way up the food chain until it reaches higher organisms like animals and us. Without the initial process of plants trapping the energy of the sun, we would not get energy from food.
The process is in theory a simple one. A plant uses water (obtained from the soil or sometimes from around itself if it is aquatic), carbon dioxide (obtained from the atmosphere) and , with the energy provided by light, splits and re-arranges the molecules to form glucose, a sugar which the plant can store to respire for energy release or convert into other chemicals which it uses for all of its processes.
Learn more the photosynthesis process steps
In actual fact, the process is far more complex than it looks and involves many chemical cycles, several organelles within plants’ cells and using different wavelengths of light according to where a plant lives (aquatic plants may use different parts of the light spectrum in order to photosynthesise because the parts of the spectrum which are normally used cannot penetrate water). and a range of chemical interactions. Photosynthesis relies on a dark reaction as well as one which occurs during light hours and without darkness the process could not be completed.
The formula for photosynthesis is six molecules of water (H2O) plus six molecules of carbon dioxide (CO2) combine, in the presence of sunlight and with the presence of chlorophyll and the catalyst of chemicals including iron, into 6 molecules of glucose (C6H12O6) plus 6 molecules of oxygen (O2).
The significance of photosynthesis is not only the fact that plants trap energy from the sun and start it transferring up the food chain to all other life on the planet but the production of oxygen. Without photosynthesis, carbon dioxide levels would increase until the earth warmed too much and suffocation of all higher life forms would be inevitable.
Photosynthesis removes a lot of carbon dioxide form the air and gives back oxygen, that life giving gas we need to exist.
We need to ensure that as many plants survive as possible because they remove and lock away much of the carbon dioxide in our atmosphere and so help control global warming and the build up of harmful carbon dioxide. Plants are as much part of our survival as the air we breathe and ultimately, all life on earth relies on the chemical process of photosynthesis.