Photosynthesis basics

Did you ever wish that you had taken Science class more seriously, especially the day they covered photosynthesis? Understanding this basic process helps make science fascinating! So, this post is about the basics of photosynthesis.

What does photosynthesis mean?

In the process of photosynthesis, plants capturing light energy and convert it to chemical energy by taking water and carbon dioxide from the air, harnessing sunlight, using chlorophyll and creating glucose (a basic sugar), water and oxygen.

Why photosynthesis is important to us

Basics of PhotosynthesisWithout photosynthesis happening in green plants, there would be no food; humans and animals rely upon this fundamental life process. What this means is, only plants can capture the energy of light and convert it to a product useful to other organisms. Aside from a small amount of energy from nuclear sources, all energy on earth is derived from the sun and plants convert that sunlight into a useful form.

The solar energy that was captured and stored as carbohydrates by plants thousands of years ago, has supplied all of the coal, oil and natural gas below earth’s surface that man uses today; and the process of photosynthesis has supplied all of the the atmospheric oxygen that earth’s residents require for life itself.

The Photosynthetic Equation

6CO2 + 12H2O —–> light and chlorophyll —–> C6H12O6 + 6H2O + 6O2

Translation: using six molecules of carbon dioxide and twelve molecules of water, while capturing light and using chlorophyll, plants produce one molecule of glucose, six molecules of water and six molecules of oxygen.

Technically, photosynthesis is the sequence of chemical reactions performed by green plants in which light energy is converted into chemical energy. In this energy-storing process, plants capture light, and using chlorophyll in the chloroplasts of the plant’s cell, convert it to food for itself (to use now or to store), while releasing carbon dioxide into the air

Four components required for photosynthesis (the inputs)

Light -For photosynthesis to happen, light must hit the chlorophyll molecules of the cell of a plant; light energy then fuses small low-energy molecules together to become larger high-energy molecules. Sunlight provides most of the light energy used in photosynthesis although plants can also use artificial light. Electric lighting can supplement or replace natural light for some horticultural and high-value greenhouse crops.

Chlorophyll – All green parts of the plant are able to photosynthesize though most occurs within the leaves. Chlorophyll molecules of healthy living plant cells will intercept sunlight to power the process of photosynthesis. Think of leaves as energy capturing solar panels turning sunlight to energy (sugar) and when they are facing full direct sunlight they’re working at full power; as soon as the plant is in the shade, production strength decreases.

Carbon dioxide (CO2) -The air we breathe is 0.03% carbon dioxide (CO2). CO2 reaches the chloroplasts (containing the chlorophyll) in leaves via tiny openings on the undersides of leaves called the stomata. CO2 supplies the carbon plus the oxygen atoms to make up glucose in the process; for every two water molecules that are split, one oxygen molecule is released into the air.

Water (H2O) – Water (H2O) provides the hydrogen (H) atoms needed in the construction of glucose. Water is also critical to other chemical reactions occurring in the process of photosynthesis but we’re just talking the basics at this point.

The products of photosynthesis (the outputs)

Glucose (C6H12O6) – Glucose is a simple sugar manufactured as a basic unit of energy in the process of photosynthesis. In sunlight, the plant is producing more glucose than it will use at that moment and the surplus is stored as either the sugar that we taste in sweet fruits and vegetables or the starch of potatoes and various starchy crops.

The glucose molecules produced in photosynthesis link together to become starch and when these chains of starch molecules are broken down they form a sugar. Most plants store their energy or their carbohydrates as starch which is less tasty to animals meaning the plant has a better chance of keeping its valuable food supply to itself.

So then why do some plants make their fruit sugary sweet? The plant’s way of ensuring that it will live on, lies within its seeds and in the nature of its fruit. What this means is that unlike people and animals, plants are immobile and depend upon outside influences to spread their seeds. In plants that have their seeds enclosed within the fruit, a colorfully sweet and delicious fruit will attract various animals that after eating the fruit, will eliminate the seeds complete with fertilizer, a distance from the parent plant, and the life of that plant continues.

Water (H2O) –Water is the source of both the hydrogen and the oxygen atoms used in the process of photosynthesis. The full biochemical role that water plays is more in depth but it’s important to know that water is both an input and an output of photosynthesis.

Basics of PhotosynthesisOxygen (O2) -The water (H2O) molecules split to provide hydrogen (H) to the glucose (C6H12O6) leaving oxygen (O2) as a product of photosynthesis. For every two molecules that split, one oxygen (O2) is released into the air via the stomata. This is the oxygen that we breathe and that makes life possible on the planet.

The bottom line? Our food, fibre, fuel and oxygen supply are all a result of it, and life as we know it could not exist without the process of photosynthesis constantly carrying on every day as the sun shines on the leaves of green plants around the world.


  1. […] The pressure from within the tiny seed will eventually break open the seed coat, the stem and cotyledons will grow upward and roots will push downward. Photosynthesis will begin as soon as the tiny new leaves and stem reach the light. More about photosynthesis […]

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