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Photosynthesis Web Resources

Bioflix Photosynthesis Animation

Simply paraphrased, photosynthesis therefore means: Plants (and certain bacteria) use light, water and carbon dioxide to put together something new: namely glucose and oxygen. So: With the help of solar energy, energy-rich organic substances are created from inorganic substances that are low in energy.

Chemically speaking, the following molecular formula describes photosynthesis:
6 CO 2 + 6 H 2 O + light energy → C 6 H 12 O 6 + 6 O 2

Here it can be seen that water (H 2 O) and carbon dioxide (CO 2 ) are required so that sugar or carbohydrates (C 6 H 12 O 6 ) and oxygen (O 2 ) can be produced through the chemical process of reduction. In detail, the process of photosynthesis is very complex and consists of several interdependent processes. Important: Photosynthesis is referred to as a redox reaction, i.e. a reduction-oxidation reaction. Both a reduction – i.e. a reaction with oxygen – and an oxidation – i.e. the withdrawal of oxygen – take place.

But where exactly does photosynthesis take place? The green plants get their color from the green leaf pigment, the chlorophyll (“chloro” comes from the Greek and means “green”). Chlorophyll is found in the membranes of chloroplasts, the organelles in plant cells. Very important: The chlorophyll can absorb sunlight, which is needed for the process. All of the photosynthesis then takes place in the chloroplast itself, which is only a few micrometers in size. There are sometimes many hundreds of chloroplasts in a single cell.

For the chemistry experts:
In general, photosynthesis can be divided into two processes that are inseparable for its success: The light reaction (primary or photo reaction) – chemical energy is provided here – and the dark reaction (secondary or synthetic reaction) that uses chemical energy from the light reaction to synthesize the high-energy substances.

What is particularly important for us as humans in photosynthesis: it produces a “waste product”, the oxygen that is essential for us and other living beings. At the same time, the CO2, which is toxic to us, is reduced because it is consumed. A perfect balance.