Photosynthesis in Chemistry
Photosynthesis can basically be described as the process by which plants use the energy from the sun to produce food for themselves. We’re going to take a look at a more complex definition of photosynthesis, and we’re take a look at what the reaction actually looks like that makes that happen.
Photosynthesis is chlorophyll containing autotrophs using the energy and sunlight to convert carbon dioxide and water into carbohydrates. Another way of saying autotrophs is by saying “primary producer.” This is basically a plant that’s not consuming anything to make its energy, it’s making its own food and energy.
Primary and secondary consumers are what consume the autotrophs. They’re not converting sunlight into carbohydrates, they’re using sunlight to power, basically, the conversion from carbon dioxide and water into carbohydrates, because light is a form of energy.
This is what the reaction actually looks like: we have light, plus six moles of carbon dioxide, and 12 moles of water to make our carbohydrate. That’s what we’re going for, but it also produces oxygen and water. Oxygen is considered a waste product, because the goal of this reaction is not to create oxygen, it’s to create this carbohydrate.
The process of photosynthesis involves two stages, the light reaction and the dark reaction. In the light reaction photons from light provide the energy to split a water molecule.
The electrons released are boosted into higher energy states, and generate reducing equivalence, and the energy carrying molecule ATP, which is an abbreviation for adenosine triphosphate. We’re going to get to that in a minute. Then we have the dark reaction, which we can also describe as the Calvin-Benson cycle.
Here atmospheric carbon dioxide is captured and converted by the reducing equivalence, and ATP into first three carbon sugars, and then later convert into six carbon sugar phosphates, and then into sucrose starch and cellulose. Notice here that ATP is used, it’s produced in the light reaction, but it’s used in the dark reaction. These two reactions are not mutually exclusive, they are dependent on each other.