Photosynthesis: The Light Reactions and The Calvin Cycle

Summary Of Photosynthesis: This video covers all the steps of photosynthesis from start to finish! Plants perform photosynthesis to create sugars. The reagents of photosynthesis are photons of light, water and carbon dioxide. The products are Oxygen, Glucose (a sugar) and a bit of water vapor.

0:00-1:05 Introduction to Photosynthesis
1:05-1:25 Reagents and Products of Photosynthesis
1:26-2:43 Location of Photosynthesis
2:43-3:25 Proteins of the Light Dependent Reactions
3:25-4:32 Photolysis
4:33-7:50 The Electron Transport Chain (aka the Light Dependent Reactions)
7:51-12:50 The Calvin Cycle (aka the Light Independent Reactions)
12:51-13:32 Summary

The Light Dependent Reactions take place across the Thylakoid membrane in the inner compartment of the chloroplasts. These reactions take in sunlight and water and generate ATP, NADPH and Oxygen. Oxygen is released through the plants’ stomata, and the ATP and NADPH are used later in the Calvin Cycle.

In the Light Dependent Reactions, photons of light strike two photosystems, as well as molecules of water. The water molecule splits into oxygen, protons and electrons in a process called “photolysis”. The oxygen diffuses out, the protons are used to establish an electrochemical gradient, and the electrons enter the electron transport chain. In the ETC, an electron is transferred from protein to protein, causing more and more protons to be pumped into the thylakoids. The electrons are ultimately transferred to NADP+ and then moved to the Calvin Cycle. The proton gradient is exploited to generate ATP using ATP synthase. The ATP will also be used later in the Calvin Cycle.

The Calvin Cycle (aka the Light Independent Reactions) takes place in the stroma; the open space inside the chloroplasts. The process combines RuBP and Carbon Dioxide using an enzyme called RuBisCo, a process we call “Carbon Fixation”. Then, it adds Hydrogen and electrons from NADPH and uses energy from ATP to reshuffle the molecules into Glyceraldehyde 3-phosphate, aka “G3P” aka “PGAL”. Two PGAL molecules are set aside to produce Glucose, while the remaining 10 are “reinvested” into the Cycle to keep it turning. The chemical reactions use both the ATP and NADPH that were generated in the Light Dependent Reactions.

Avoid plagiarism! Cite BOGObiology! Copy and Paste the Following APA Citation:

#photosynthesis #lightdependentreactions #calvincycle #electrontransportchain #carbonfixation

NGSS: HS-LS1-5

[thekid]

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[ashvathsingh]

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[billiestump]

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[Vu]

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[mattmorrissette]

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