Photosynthesis "WHat makes the world go 'round"

All Organisms need energy to live, and because plants do not "eat" other organisms for energy they are called Photoautotrophs. Photoautotrophs convert light energy from the Sun into chemical energy for the cell to use. The process is call PHOTOSYNTHESIS.

Photosynthesis occurs in two phases. Light Dependent Reaction and The Calvin Cycle (Light In-Dependent reaction) The First phase is The Light Dependent Reaction. This process occurs in the Thylakoids of Chloroplast that is located inside of cells. The light-dependent reaction occurs on the thylakoid membrane and the Calvin Cycle occurs in the stroma.

Step #1 & #2

  1. When light hits photosystem 2, it causes multiple processes to happen. First an electron is excited from the light energy. In the meantime, a water molecule is split releasing another electron for the electron transport and releasing hydrogen for chemiosmosis and waste oxygen.
  2. Once the the electron is excited, it starts following the electron transport chain. Then it comes to a electron-acceptor molecule. Here, hydrogen molecules can come into the thylakoid space also building up for up for chemiosmosis.

Steps #3 & #4

3. During these processes, the electron looses energy, so it goes to Photosystem 1 and is re-energized with light.

4. From there the electron travels to a final protein called ferrodoxin. Ferrodoxin transfers the electrons to the electron carrier NADP+, forming NADPH and sending it to the calvin cycle.

Step #5

Chemiosmosisis is the movement of hydrogen ions across a membrane to the lesser gradient. More specifically, it is a process that takes built up hydrogen and sends it to the Calvin Cycle, and it takes ADP and breaks it into ATP (in the ATP synthase) and also sends it to the Calvin Cycle

Chemiosmosis Picture

The Calvin Cycle


  1. RUBP meets up with carbon that came through the pores of plants. (stomata)
  2. Then it forms PGA.
  3. After that ATP and NADPH is added for energy and electrons forming G3P.
  4. From there, some is formed into sugars, but only a small percentage.
  5. The remaining G3P hits an enzyme called rubisco forming it back into RUBP.

As one can see, photosynthesis is a complex process that all plants need to live.


Created with images by Michael Gwyther-Jones - "NORWAY" • Pexels - "field summer plant" • JamesWatkins - "Kansas Summer Wheat and Storm Panorama" • tpsdave - "corn cornfield field" • k_r_craft - "tree oak landscape" • Pexels - "creek fall hd wallpaper" • Clearwater1967 - "Rainbow" • 雷太 - "Red flower" • mjneuby - "Yellow Flower" • Hans - "field of rapeseeds oilseed rape blütenmeer" • EinarStorsul - "dandelion field flower"

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