Photosynthesis

Page
4

Uses ATP and NADPH from light reaction as energy

Uses CO2

To produce glucose: it takes 6 turns and uses 18 ATP and 12 NADPH.

Slide 38

38

Chloroplast

Slide 39

39

Calvin Cycle (C3 fixation)

Slide 40

40

Calvin Cycle

Remember: C3 = Calvin Cycle

Slide 41

41

Photorespiration

Occurs on hot, dry, bright days

Stomates close

Fixation of O2 instead of CO2

Produces 2-C molecules instead of 3-C sugar molecules

Produces no sugar molecules or no ATP

Slide 42

42

Photorespiration

Because of photorespiration, plants have special adaptations to limit the effect of photorespiration:

1. C4 plants

2. CAM plants

Slide 43

43

C4 Plants

Hot, moist environments

15% of plants (grasses, corn, sugarcane)

Photosynthesis occurs in 2 places

Light reaction - mesophyll cells

Calvin cycle - bundle sheath cells

Slide 44

44

C4 Plants

Slide 45

45

CAM Plants

Hot, dry environments

5% of plants (cactus and ice plants)

Stomates closed during day

Stomates open during the night

Light reaction - occurs during the day

Calvin Cycle - occurs when CO2 is present

Slide 46

46

CAM Plants

Slide 47

47

Question:

Why do CAM plants close their stomata during the day?

Slide 48

Cam plants close their stomata in the hottest part of the day to conserve water

Slide 49