Photosynthesis

What do we call the process plants and algae use to produce sugar?

Bacterium

A single-celled organism that can be found everywhere in our surroundings. Some of them can cause diseases while others are essential to life.

Cyanobacteria

Bacteria that live in water and can perform photosynthesis and fix nitrogen from the air.

Photosynthesis

The process whereby special cells in an organism, usually a plant, use sunlight, water and carbon dioxide to create energy in the form of glucose. Takes place in cells that contain a green pigment called chlorophyll.

Cellulose

A material that makes up plant cell walls and consists of several thousand glucose molecules.

Glucose

A simple sugar that can be quickly broken down into energy in an organism. It is found naturally in plants.

Starch

A tasteless substance made up of a long chain of glucose molecules that is found in foods like rice and potatoes. They are called slow carbohydrates because the body needs a long time to digest them. Starch is also the main form in which plants store carbohydrates.

Alga

A simple organism that lives in water and can perform photosynthesis.

Chloroplast

The part in a plant cell where photosynthesis occurs and contains a substance called chlorophyll.

Chlorophyll

A green substance in plants and certain other living things that makes it possible for them to capture sunlight to perform photosynthesis.

Stoma

One of many tiny openings in a plant leaf through which carbon dioxide is absorbed from the air, and oxygen and water are released into the air.

Tuber

A short, thick, round stem, usually found underground, which has buds that can produce new plants.

- Ah, isn't this a lovely day! - ... For WHAT? An invigorating walk in the forest, perhaps? I feel full of energy! ... I have no energy at all.

But you've eaten food today? - Yeeeees... - You do remember, right? Both humans and animals need food to get energy! Yeah... but how about TREES! It's not like they eat hamburgers.

No, plants and algae don't need to eat, they get their energy from something called... photosynthesis! Photo-what? To us, the leaves look green because they are full of a substance called chlorophyll. The chlorophyll takes up energy from the sun and uses it to make energy for the plant.

Looking at a cross section of a leaf, we find all the components necessary for photosynthesis. Here is water that has been absorbed via the roots, and carbon dioxide that has been absorbed through small openings underneath the leaves - stomata. Energy from sunlight is caught by small green sections of the cell full of chlorophyll - chloroplasts. Here in the chloroplasts water and carbon dioxide are combined using sun energy and transformed into glucose. At the same time, oxygen is created that animals and plants breathe.

The glucose is stored as starch. Starch consists of 3-400 glucose molecules in a row. Some plants, for example potatoes, store starch in tubers. Other plants, for example wheat, have big stores of starch in their seeds. Plants can also build cellulose out of glucose, which for example makes up tree trunks.

Cellulose consists of more than a thousand glucose molecules. But if there were no plants, wouldn't there be any oxygen to breathe then? No, that's right! Almost all life on earth is dependent on photosynthesis. Without photosynthesis, almost no life!

Some of the oxygen in the atmosphere comes from photosynthesis in land plants, but most comes from algae and from a group of bacteria in the ocean called cyanobacteria. But I still don't get it: how exactly does photosynthesis work then? Green plants take up water through their roots. In the air there is carbon in the form of carbon dioxide, that is taken up by the stomata on the underside of the leaf. In the leaves there are chloroplasts with chlorophyll that transforms the carbon dioxide and water, with the help of sun energy, into oxygen and glucose.

Land plants, algae and cyanobacteria in the ocean can all perform photosynthesis. If photosynthesis is described with a chemical formula it looks like this: Six carbon dioxide molecules, plus six water molecules, plus energy from the sun, turns into six oxygen molecules and a glucose molecule. Cool! So we're really walking around amongst a bunch of factories that manufactures sugar and oxygen! Yeah, that's right!

Very important little factories that are necessary for almost all life on earth. Factories that make the oxygen we breathe and the food we eat!