1. Section 8.2
Light Reactions

3. A) Electron Transport ( Beginning of Light Reaction)
12 H2O + 12 NADP + 18 ADP →
6 O NADPH + 18 ATP (don’t copy)

4. A) Electron Transport
1) Photosystem: a cluster of pigment molecules a) Examples:
2) Start:
a) Accessory pigment molecules Photosystem I & 2 absorb light
b) Energy is passed to specific pair of ___________

5. A) Electron Transport
Step 1) Energy forces electrons to enter a higher energy level in chlorophyll a of Photosystem II  electrons become excited

6. A) Electron Transport
Step 2: Excited electrons leave _________ by oxidation reaction, while primary electron acceptor accepts _________

7. A) Electron Transport
Step 3: Primary Electron acceptor gives electrons molecules in thylakoid membrane in the electron transport chain (ETC)

8. A) Electron Transport Step 4: During step 2
electrons move from a pair of ________ molecules in Photosystem 1 to primary electron acceptor

10. A) Electron Transport
Step 5: Primary electron acceptor from photosystem 1 sends _______ to another ETC
electrons combine with a proton and NADP+ to form NADPH
_________ + proton + NADP+  NADPH

11. Critical Thinking What does the Electron Transport Chain do?
What is Photosystem I and II?
What is a pigment and what is an example of a pigment?
Why are electrons needed in Photosynthesis?

12. B) Restoring Photosystem II
Photosystem II must constantly send electrons to Photosystem I, therefore:
2H2O  4H+ + 4e- + O2

13. C) Chemiosmosis
Chemiosmosis: process by which ATP is made during light reactions
Protons must create a ___________
Energy from the gradient is used by an enzyme in the thylakoid membrane  __________
ATP Synthase will _________________ to ADP to form ATP