What Are The Reactants Of Photosynthesis?

Photosynthesis as we all know is simply the process by which green plants and certain other organisms transform light energy into chemical energy.

Then, what are the likely reactants of photosynthesis?

Photosynthesis requires sunlight, carbon dioxide, and water as main reactants. When photosynthesis is complete, oxygen is released and carbohydrate molecules, most commonly glucose, are formed.

The importance of photosynthesis in sustaining life on Earth cannot be overstated. If photosynthesis stops, soon there will be little food and other organic matter left on Earth.

Most organisms would disappear, and over time the Earth’s atmosphere would be virtually devoid of oxygen gas.

The only organisms capable of existing under such conditions would be chemosynthetic bacteria, capable of using chemical energy from certain inorganic compounds and thus independent of light energy conversion.

The energy derived from photosynthesis performed by plants millions of years ago is responsible for the fossil fuels (i.e., coal, oil and gas) that power industrial society.

In past centuries, green plants and small organisms that fed on plants grew faster than they were consumed, and their remains were deposited in the Earth’s crust by deposition and other geological processes.

There, protected from oxidation, these organic residues were slowly transformed into fossil fuels.

Not only do these fuels provide most of the energy used in factories, households, and transportation, but they also serve as raw materials for the production of plastics and other synthetic products.

Unfortunately, modern civilization has used up the excess photosynthetic production accumulated over millions of years over several centuries.

Consequently, carbon dioxide, which has been removed from the air to produce carbohydrates by photosynthesis for millions of years, is returning at an incredible rate.

The concentration of carbon dioxide in the Earth’s atmosphere is increasing at the fastest rate in the history of the Earth, and this phenomenon is expected to have serious consequences for the Earth’s climate.

Photosynthetic Products

As has been stated, carbohydrates are the most-important direct organic product of photosynthesis in the majority of green plants. The formation of a simple carbohydrate, glucose.

Little free glucose is produced in plants; instead, glucose units are linked to form starch or are joined with fructose, another sugar, to form sucrose.

Photosynthesis synthesizes not only carbohydrates, as once thought, but also amino acids, proteins, lipids (or fats), pigments, and other organic components of green tissues.

Minerals supply the elements (e.g., nitrogen, N; phosphorus, P; sulfur, S) needed to form these compounds.

Chemical bonds are broken between oxygen (O) and carbon (C), hydrogen (H), nitrogen, and sulfur, and new bonds are formed in products that include gaseous oxygen (O2) and organic compounds.

It takes more energy to break bonds between oxygen and other elements (e.g., in water, nitrates, and sulfates) than is released when new bonds are formed in the products.

This difference in bonding energy accounts for most of the light energy stored as chemical energy in the organic products produced during photosynthesis.

Additional energy is stored during the formation of complex molecules from simple ones.

Credit:

https://www.britannica.com/science/photosynthesis/Basic-products-of-photosynthesis