Photosynthesis

Photosynthesis is the process plants use to convert the sun’s energy into glucose (sugar). When the sun’s electromagnetic energy hits living plant leaves, some crazy chemistry starts to happen!


​Did you know that plants only absorb red and blue wavelengths of sunlight? That is why they appear green when we look at them. They are actually reflecting/rejecting green light!

Photosynthesis (At09kg, et al) CC BY-SA 4.0

Photosynthesis occurs in an organelle called a chloroplast. Organelles are organs found within a cell. The chloroplast holds chlorophyll, water (H20), oxygen (O2), carbon dioxide (CO2) and glucose (C6H12O6).

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How photosynthesis happens
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Photosynthesis is a two step process. The first step is the light dependent reaction. This is when the sunlight is absorbed and transformed into a chemical called ATP. To do this, electrons are torn from water molecules, creating oxygen as a waste product. When this happens, hydrogen (H) is released and used to create two compounds: NADPH (nicotinamide adenine dinucleotide phosphate) and more ATP (adenosine triphosphate).


The second stage of photosynthesis is the light independent reaction, or the Calvin Cycle. This is when the ATP is converted into glucose using carbon dioxide. 


Once the glucose is formed, it is used by garden plants to grow and thrive. These sugar molecules are also used as currency with the soil microorganisms that provide plants with mineral elements found in the soil.


Any interruption in photosynthesis leads to chlorosis. Chlorosis can be the result of disease, a lack of mycorrhizae, or sunburn. If you see chlorosis occurring anywhere in your garden, your plants are starving. Of course, if you want tall, light-colored stalks of celery, you must block photosynthesis from happening by wrapping the stalks with newspaper or some other material.