Photosynthesis: Part 5: Light Reactions | HHMI BioInteractive Video

This animation provides a detailed look at the chemical processes in the light reactions of photosynthesis. It is appropriate for advanced high school biology through college-level students.

The light reactions of photosynthesis transform light energy into chemical energy stored in molecules of ATP and NADPH. Chlorophyll molecules absorb photons of light in two photosystems, which are embedded in the thylakoid membrane of the chloroplast. The photons energize electrons in the chlorophyll molecules, which drives the electrons through a series of oxidation and reduction reactions in photosystem II. Meanwhile, more electrons are released by the splitting of water molecules, which produces oxygen as a byproduct.

The energy from the light-energized electrons generates a proton (hydrogen ion) gradient. As protons flow through ATP synthase, ATP is formed. Photons energize electrons again at photosystem I, eventually forming the NADPH molecule. Both ATP and NADPH provide energy for making sugars in the Calvin cycle.

To view the rest of this series on photosynthesis, go to the full playlist at    • Photosynthesis: Part 1: Overview | HH...  

To view a specific part of the series, use the following links:

Part 1: Overview
   • Photosynthesis: Part 1: Overview | HH...  
Part 2: Chemical Process
   • Photosynthesis: Part 2: Chemical Proc...  
Part 3: Leaf Structure
   • Photosynthesis: Part 3: Leaf Structur...  
Part 4: Chloroplasts
   • Photosynthesis: Part 4: Chloroplasts ...  
Part 5: Light Reactions
   • Photosynthesis: Part 5: Light Reactio...  
Part 6: Calvin Cycle
   • Photosynthesis: Part 6: Calvin Cycle ...  
Part 7: Biosynthesis
   • Photosynthesis: Part 7: Biosynthesis ...  

To view the entire series as a full-length animation, use the following link:    • Photosynthesis | HHMI BioInteractive ...  

To download these animations and discover related material, go to https://www.biointeractive.org/photos...