Onion epidermal cell Onion epidermal cell The epidermal cells of onions provide a protective layer against viruses and fungi that may harm the sensitive tissues. Because of their simple structure and transparency they are often used to introduce students to plant anatomy or to demonstrate plasmolysis. The clear epidermal cells exist in a single layer and do not contain chloroplasts, because the onion fruiting body (bulb) is used for storing energy, not photosynthesis. Each plant cell has a cell wall, cell membrane, cytoplasm, nucleus, and a large vacuole. The nucleus is present at the periphery of the cytoplasm. The vacuole is prominent and
Photoelectrochemical cell Photoelectrochemical cell Photoelectrochemical cells or PECs are solar cells that produce electrical energy or hydrogen in a process similar to the electrolysis of water. This type of cell electrolizes water to hydrogen and oxygen gas by irradiating the anode with electromagnetic radiation. This has been referred to as artificial photosynthesis and has been suggested as a way of storing solar energy in hydrogen for use as fuel. Incoming sunlight excites free electrons near the surface of the silicon electrode. These electrons flow through wires to the stainless steel electrode, where four of them react with four water molecules to form