Question

1. label the numbered components of the photosystem below. below the image, briefly describe what is happening in this image.
2. complete the drawing below to illustrate both cyclic and non - cyclic electron flow during the light - dependent reaction. show the source of the electrons, the movement of the electrons, as well as the production of o₂, atp and nadph.

electron transport chain
ps ii (p680) ps i (p700) nadp+ reductase

Explanation:

For question 8, typically in a photosystem diagram, 1 could be light energy (photon), 2 could be light - harvesting complex pigments, 3 could be the reaction - center chlorophyll. The overall process is the absorption of light energy by the light - harvesting complex which is then funneled to the reaction - center chlorophyll, exciting an electron. For question 9, in non - cyclic electron flow, electrons come from water (source), move through PS II, electron transport chain, PS I and finally to NADP+ to form NADPH. Oxygen is produced as a by - product of water splitting in PS II. ATP is produced through chemiosmosis as protons flow through ATP synthase. In cyclic electron flow, electrons cycle back from PS I to the electron transport chain instead of going to NADP+, producing only ATP.

Answer:

For question 8:

1. Light energy (photon)
2. Light - harvesting complex pigments
3. Reaction - center chlorophyll

Process: Light energy is absorbed by light - harvesting complex and transferred to reaction - center chlorophyll, exciting an electron.
For question 9:
Non - cyclic electron flow:
Source of electrons: Water
Electron movement: Water → PS II → Electron transport chain → PS I → NADP+ (to form NADPH)
Oxygen production: By - product of water splitting in PS II
ATP production: Through chemiosmosis as protons flow through ATP synthase
Cyclic electron flow:
Electron movement: PS I → Electron transport chain (back to PS I), producing only ATP