1. Photosynthesis

2. (emphasizes production of glucose
SUMMARY EQUATION
6CO H2O + light  C6H12O O2 + 6H2O
6CO H2O + light  C6H12O O2
CO2 + H2O + light  CH2O + O2
(emphasizes production of glucose
1 carbon at a time)

3. SITE OF PHOTOSYNTHESIS -- PLANTS

4. SITE OF PHOTOSYNTHESIS – PROKARYOTES
Lack chloroplasts
Chlorophyll built into plasma membrane

5. Structure of Chloroplasts

6. Overview of photosynthesis
Light
CO2
Light Rxns (
thylakoids) H 2 O
NADP +
NADPH
ADP P
ATP
Calvin
Cycle
stroma) CH •
Take e- from H2O
Use light energy to
boost e- to higher
energy level
Use some energy to
make ATP
Add high energy e-
to NADP+
Calvin Cycle
AKA Dark Rxn
Uses ATP produced in
light rxn
Takes high energy e-
from NADPH and adds
them to CO2
Produces sugar 1 carbon
at a time
Overview of photosynthesis

7. LIGHT REACTIONS – CYCLIC ELECTRON FLOW-PHOTOSYSTEM I
Few 100 pigment molecules (chlorophyll a, b, & carotenoids)
Reaction center
Chlorophyll a molecule
Bound to specific proteins
Closer to 1o electron acceptor
Antenna pigments absorb photons and pass to rxn center

8. LIGHT REACTIONS – NONCYCLIC ELECTRON FLOW-PHOTOSYSTEM II & I
P680 photosystem II

9. Calvin Cycle Vocabulary (just know abbreviations)
RuBP = ribulose biphosphate
Rubisco = RuBP carboxylase
PGA = phosphoglycerate
DPGA = diphosphoglycerate
G3P= glyceraldehyde phosphate
RuP = ribulose phosphate

10. Calvin Cycle-Light Independent Reaction Location-stroma
5 G3P
6 G3P
1 G3P
2 G3P

11. Problem: Photorespiration
If [O2] > [CO2] in leaves
Rubisco fixes O2 instead of CO2
5-C compound produced
5-C  1 PGA enters Calvin Cycle
1 glycolate (2-C) exits chloroplasts and enters peroxisomes
Decreases productivity
Fostered by hot, dry, bright days

12. C4 Plants Fix CO2 as 4C compound
Segregate CO2 fixation from Calvin cycle
Acts as CO2 pump
PEP carboxylase has lower affinity for O2 than rubisco
Adaptation in hot regions with intense light

13. CAM PLANTS Crassulacean Acid Metabolism