La photosynthèse

Historically, plants have transformed sunlight into chemical energy for their energy needs. This phenomenon, photosynthesis, can only be studied thanks to the findings of scientists Joseph Priestley and Jan Ingen-Housz.

The process of absorbing light mainly occurs thanks to the chlorophyll which is located directly under the surface of the leaf. The pigments gather in reaction centers called photosystems.

Computer animation tracks the passage of electrons and protons through the P680 and P700 photosystems and into the stroma. Photosystems convert solar energy into chemical energy, thereby producing ATP.

The dark reaction takes place in the stroma and generates the end products of photosynthesis: glucose, cellulose, protein and starch. The energy used comes from the products of clear reactions.

Explanation of how plants use carbon dioxide from the atmosphere. A study at the molecular level makes it possible to distinguish between the plants which carry out their photosynthesis in C-3 and those which carry out it in C-4.

The California redwood tree serves as an example to illustrate the double vascular system of plants. The xylem and phloem are used to transport water and carbohydrates, which allows the plant to grow and reach its place in the sun.