THE BASIC NEEDS FOR PHOTOSYNTHESIS

Authors Avatar
THE BASIC NEEDS FOR PHOTOSYNTHESIS

Plants, as well as some Protists and Monerans, can take small molecules from the environment and bind them together using the energy of light. The incoming light energy is transformed into the energy holding the new molecules together, and the organisms use those molecules as an energy "fuel." The basic process can be represented this way:

CO2 + H2O light > C6H12O6 + O2

Carbon Dioxide Water (sugar) Oxygen

In the case of water organisms, the carbon dioxide and water are from their immediate surroundings; for most land plants, the water is absorbed from the soil and the carbon dioxide from the atmosphere.

The glucose is used for two major purposes: 1) it serves as an energy reserve for periods of darkness (don't forget that photosynthesizers, like any living things, require energy and get it through respiration processes, commonly aerobic respiration, and 2) it is used as a major component of structure: the cell walls that surround almost all photosynthetic cells are made of starches, huge molecules made up of hundreds, commonly thousands, of sugar molecules bound together. This is why plant fibers are great sources of nutrition if you can break them down, which is difficult - we humans can't, being limited to the simpler starches put into seeds and fruits and tubers as accessible energy stores.
Join now!


Keep in mind that photosynthetic organisms are still living things, with protein-based chemistry, which means that they have nutritional requirements beyond carbon dioxide and water. Proteins, unlike sugars and starches, contain a significant amount of nitrogen, which usually needs to be absorbed as nitrates (a nitrogen-oxygen molecule) to be usable. The production and use of glucose for energy also requires ATP as an energy carrier; ATP contains phosphorus, usually absorbed as phosphates (a phosphorus-oxygen molecule). Anyone who takes care of plants knows that nitrates and phosphates are important ingredients in fertilizers. Most photosynthesizers have a few critical molecules ...

This is a preview of the whole essay