Chapter 1: Introduction

• Photosynthesis is the process of converting sunlight, carbon dioxide, and water into glucose and oxygen

• Photosynthesis is a complex and inefficient process

• There are two main reactions in photosynthesis: light-dependent reactions and light-independent reactions (Calvin cycle)

Chapter 2: Called Chlorophyll

• Plants obtain water through their roots and transport it to the leaves through xylem

• Carbon dioxide enters and oxygen exits the leaves through stomata

• Chlorophyll is the pigment responsible for absorbing photons from the sun

• Chloroplasts are plastids found in plant cells and contain chlorophyll

• Chloroplasts have a complex internal structure with thylakoids and grana

Chapter 3: Convert The Energy

• Photosynthesis begins with the absorption of a photon by a molecule of chlorophyll

• Light-dependent reactions convert the energy of the absorbed photon into a usable form

• Photosystem 2 is a complex of proteins and molecules that contains chlorophyll

• Photosystem 2 is the first of four protein complexes involved in the light-dependent reactions

Chapter 4: Electrons Lose Their Energy

• Electron transport chain

  • PS 2's chlorophyll transfers excited electron to a mobile electron carrier

  • PS 2 splits water molecule to replenish lost electron

  • Byproducts of water splitting: hydrogen ions and oxygen

Chapter 5: Bit Of Energy

• Cytochrome complex

  • Serves as intermediary between PS 2 and PS 1

  • Pumps a proton into the thylakoid, charging it like a battery

• Synthase enzyme

  • Uses energy from protons to convert ADP to ATP

Chapter 6: The Calvin Cycle

• Photosystem 1 (PS 1)

  • Similar to PS 2, but with different products

  • Electrons combine with another electron carrier

  • NADP plus accepts 2 electrons and 1 hydrogen ion to become NADPH

• Chemical energy in the form of ATP and NADPH

• Calvin cycle (light independent reactions)

  • Uses ATP and NADPH to produce useful substances

  • Carbon fixation: CO2 is fixed to RUBP with the help of Rubisco enzyme

Chapter 7: Dependent Reactions Plants

• A one-celled organism evolved an enzyme called Rubisco to convert inorganic carbon into organic carbon

  • Rubisco was not very efficient, but better than relying on chemically formed organic carbon

  • Organism produced a large amount of Rubisco to compensate for its inefficiency

• Rubisco became the dominant form of life on Earth

• Increased oxygen in the atmosphere caused confusion for Rubisco

  • Rubisco started reacting with oxygen instead of CO2, creating a toxic byproduct called phosphoglycolate

  • Plants had to develop specialized enzymes to break down phosphoglycolate

• Plants continue to produce large amounts of Rubisco

  • Estimated 40,000,000,000 tons of Rubisco on the planet

Chapter 8: Need Some Energy

• Ribulose bisphosphate (RUBP) combines with CO2 and becomes unstable

• The unstable 6-carbon chain breaks apart into 3 phosphoglycerate molecules

• In the second phase of the Calvin cycle, ATP and NADH provide energy

  • ATP adds a phosphate group to 3 phosphoglycerate

  • NADH adds electrons to 3 phosphoglycerate

  • Glyceraldehyde 3 phosphate (G3P) is produced

• G3P is a high-energy compound that can be converted into various carbohydrates

  • Glucose for short-term energy storage

  • Cellulose for structure

  • Starch for long-term storage

• 5 G3Ps are needed to regenerate the 3 RUBPs

• 9 ATP and 6 ADPH molecules are also required

Chapter 9: Conclusion

• Photosynthesis converts sunlight, water, and carbon dioxide into all living things

• 3 RUBPs are converted into 6 G3Ps, but only one G3P is used

• The remaining G3Ps are needed to regenerate the original RUBPs

• Regeneration is the final phase of the Calvin cycle

Selected references and the option to rewatch the video are provided for further understanding.