Photosynthesis and Van Helmont Experiment

Follow us: All energy on Earth comes from a star, the Sun. Light must travel 160 million kilometers to reach Earth where plants capture this light energy and convert it to chemical energy in the form of sugars. This biochemical process is called PHOTOSYNTHESIS. The summary equation for photosynthesis is shown here. Carbon dioxide from the atmosphere, plus water, in the presence of light and chlorophyll found in plants, produces sugars and releases oxygen into the atmosphere as a byproduct of these reactions. Plants and other photosynthetic organisms like algae are termed autotrophs, because they can make their own food, while animals, termed heterotrophs, must obtain their food from other sources. During the metabolism of food molecules, animals and plants give off carbon dioxide and water. This is the aquatic plant, Elodea, which is undergoing PHOTOSYNTHESIS. Mouse over the bubbles on the leaves to identify their chemical nature. These bubbles are the oxygen gas that is being released during photosynthesis. When the Earth was formed several billion years ago, its atmosphere did not contain oxygen. The development of an oxygen-containing atmosphere only occurred after PHOTOSYNTHESIS had evolved in the earliest prokaryotic organisms. Eukaryotic plants eventually evolved from aquatic ancestors (green algae) and formed the oxygen-rich atmosphere that the Earth currently possesses. The concept that some organisms can manufacture their own food was not an intuitive idea to...