What is Photosynthesis?
- Plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates.
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Autotrophs vs. Heterotrophs

Heterotrophs: Organisms that obtain food by consuming other living things. Some obtain food from plants indirectly by feeding on plant- eating animals.

Autotrophs: Organisms that make their own food. All lfe on Earth, including humans, depend on the ability of autotrophs to capture the energy of sunlight and store it in the molecules that make up food.

The ATP Molecule

The most important compounds that cells use to store and release energy is adenosine triphosphate, ATP. ATP consists of adenine, a 5- carbon sugar called ribose, and three phosphate groups. Phosphate groups are the key to ATP's ability to store and release energy.

ADP is a compound that look almost like ATP, except that it has two phosphate groups instead of three. A cell that has available energy, can store small amounts of it by adding phosphate groups to ADP molecules, producing ATP.
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Why is ATP useful to cells?
ATP can easily release and store energy by breaking and re-forming the bonds between is phosphate groups. This characteristic of ATP makes it exceptionally useful as a basic energy source for all cells.

The Equation of Photosynthesis
external image photosynthesis-equation.gif

Limiting Factors to Photosynthesis

The three limiting factors to photosynthesis is temperature, sunlight, and water. If the temperature is not between 0 and 30 degrees celsius then the process may not work as well as it could. Sunlight and water are also very important because if you have too little or too much of each of them, then the cycle could be affected and malfunction.

Light Reaction VS. Dark Reaction

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Light-Dependent Reactions
  • Light
  • Water
  • ADP
  • NADP+

  • Oxygen
  • ATP

Light-Independent Reactions
  • Carbon Dioxide
  • ATP

  • Sugars