Brittany Devendorf
March 26, 2013
Wooley
Botany
Photosynthesis
To a plant, sunbathing is a required action for life. In fact, plants have evolved in all sorts of ways to maximize their exposure to the sun while at the same time preventing loss of critically needed water. Plants, as well as some algae and bacteria, perform photosynthesis, a process that involves the capture and use of the Sun’s energy to create biological compounds. Photosynthetic organisms generate these compounds using carbon dioxide (CO2) and water (H2O), and the products they release are oxygen (O2) and carbohydrates as byproducts.
Plants provide us with the oxygen we breathe, so the lower the number of plants on the planet, the less O2 produced for important things like breathing. Photosynthesis is a fairly complex chemical system that can be divided into two processes. In the first phase of photosynthesis, cellular protein pigments called chloroplasts are excited by light that propels them into high-energy states. The chloroplasts then transfer this energy through electrons to other protein complexes. This group of proteins is called the electron transport chain. The proteins operate similarly to a group of dominoes: after the first one has been pushed, each protein transfers energy to each member along down the line.
Water is split in this process, releasing oxygen and hydrogen ions. The electrons from the electron transport chain combine with these hydrogen ions and nicotinamide adenine dinucleotide phosphate ions (NADP+) to form adenosine triphosphate (ATP) and a reduced unit of NADP+, called
NADPH (NADP plus an electron, or H). These energy storage forms, ATP and NADPH, are used to convert

carbon dioxide (CO2) to build carbohydrates during the second phase of photosynthesis. Plants can then break down these carbohydrates to fuel their existence.

Sources: http://library.thinkquest.org/3715/photo3.html http://science.howstuffworks.com/environmental/earth/geophysics/earth3.htm