Photosynthesis Pathways Overview

What end products are generated from Non-Cyclic Photophosphorylation?

Which process describes the return of electrons to the chlorophyll molecule?

What role do protons play in Non-Cyclic Photophosphorylation?

During the Dark Stage, what is the primary source of energy for producing glucose?

What occurs in the stroma of the chloroplast during the Dark Stage?

Light Stage

Pathway 1: Cyclic Phosphorylation (Grana)
- Light energy excites electrons in chlorophyll.
- Excited electrons are passed down electron carriers.
- Energy from electron transfer creates ATP from ADP and inorganic phosphate.
- This reaction returns electrons to the chlorophyll.
- End product: ATP
Pathway 2: Non-Cyclic Photophosphorylation (Grana)
- Light energy excites two electrons in chlorophyll.
- Excited electrons are passed down electron carriers.
- Energy from electron transfer creates ATP from ADP and inorganic phosphate.
- Electrons combine with NADP+ to form NADPH.
- Electrons do not return to the chlorophyll.
- Water is split into protons (H+), electrons (e-), and oxygen (O2), replenishing electrons lost from chlorophyll.
- Protons accumulate in a proton pool and are used to create NADPH.
- End products: ATP, NADPH, O2

Dark Stage

Location: Stroma
Energy Source: ATP breakdown
Process: CO2 from the air enters the chloroplast.
NADPH donates its electrons and protons to CO2, forming glucose (C6H12O6).
NADP+ is regenerated for use in the light stage.
ADP is regenerated for use in the light stage.
End product: Glucose

Explore the two main pathways of photosynthesis: Cyclic and Non-Cyclic Photophosphorylation. Understand how light energy is converted into ATP and NADPH, and the role of chlorophyll and water splitting in these processes. Test your knowledge on the significance of these pathways in the overall process of photosynthesis.