1. Atlantic Ocean in Winter Fig. 6-1a p.92

2. Fig. 6-2, p.94

3. Fig. 6-3, p.95

4. p.97

5. photosynthetic cells upper epidermis leaf vein lower epidermis a Zooming in on a photosynthetic cell. Fig. 6-6a, p.97

6. two outer membranes of chloroplasts stroma part of thylakoid membrane system bathed in stroma: thylakoid compartment, cutaway view b Chloroplast structure. No matter how highly folded, its thylakoid membrane system forms a single, continuous compartment in the stroma. Fig. 6-6b, p.97

7. sunlight O2 H2O CO2 CHLOROPLAST NADPH, ATP light- dependent reactions light- independent reactions NADP+, ADP sugars CYTOPLASM c In chloroplasts, ATP and NADPH form in the light-dependent stage of photosynthesis, which occurs at the thylakoid membrane. The second stage, which produces sugars and other carbohydrates, proceeds in the stroma. Fig. 6-6c, p.97

8. electron transfer chain light energy electron transfer chain light energy NADPH Photosystem II Photosystem I THYLAKOID COMPARTMENT THYLAKOID MEMBRANE oxygen (diffuses away) STROMA Fig. 6-8b, p.99

9. a CO2 in air spaces inside a leaf diffuses into a photosynthetic cell. Six times, rubisco attaches a carbon atom from CO2 to the RuBP that is the starting compound for the Calvin–Benson cycle. f It takes six turns of the Calvin–Benson cycle (six carbon atoms) to produce one glucose molecule and regenerate six RuBP. 6CO2 b Each PGA molecule gets a phosphate group from ATP, plus hydrogen and electrons from NADPH. The resulting intermediate is called PGAL. e Ten of the PGAL get phosphate groups from ATP. In terms of energy, this primes them for an uphill run—for the endergonic synthesis reactions that regenerate RuBP. 12 ATP 12 PGA 6 RuBP 6 ADP 12 ADP + 12 Pi Calvin-Benson cycle 6 ATP 12 NADPH 4 Pi 12 NADP+ d The phosphorylated glucose enters reactions that form carbohydrate products—mainly sucrose, starch, and cellulose. c Two of the twelve PGAL molecules combine to form a molecule of glucose with an attached phosphate group. 10 PGAL 12 PGAL 1 Pi phosphorylated glucose Fig. 6-10, p.101

10. Fig. 6-11, p.102

11. Fig. 6-12, p.103

12. sunlight Light- Dependent Reactions H2O O2 NADPH ADP + Pi NADP+ ATP Light- Independent Reactions Calvin-Benson cycle H2O CO2 phosphorylated glucose end products (e.g., sucrose, starch, cellulose) Fig. 6-13, p.104

13. p.104

14. p.105a