
Name some common producers
› Plants, algae, some protists, cyanobacteria

Define photoautotroph
› An organism that uses light energy to
produce food

Define chemoautotroph
› An organism that uses chemical energy to
produce food
Fig. 10-2
(a) Plants
(c) Unicellular protist
10 µm
(e) Purple sulfur
bacteria
(b) Multicellular alga
(d) Cyanobacteria
40 µm
1.5 µm

State the organelle of photosynthesis
› Chloroplast

Where are chloroplasts concentrated in
plants?
› The green tissue on the interior of the leaf
› Mesolphyll
Fig. 10-3a
Leaf cross section
Vein
Mesophyll
Stomata
Chloroplast
CO2
O2
Mesophyll cell
5 µm

Explain how gases are exchanged
between the plant and the environment.
› Stoma are openings in the epidermis of
leaves
› Guard cells surround the stoma and they
regulate the opening & closing of the stoma
› When open, CO2 can enter while O2 and
H2O can exit
Fig. 10-3b
Chloroplast
Structure
of the
chloroplast
Thylakoid is
site of light
reactions
Stroma is
site of
Calvin
Cycle
Outer
membrane
Thylakoid
Stroma
Granum
Thylakoid
Space
(lumen)
Intermembrane
space
Inner
membrane
1 µm
1950’s – scientists used heavy isotope of
oxygen (18O) to follow oxygen through
photosynthesis.
 Tagged oxygen of CO2 and found no
tagged O2 given off
 Tagged O2 of H2O and found tagged O2
given off

Fig. 10-4
Reactants:
Products:
6 CO2
C6H12O6
12 H2O
6 H2O
6 O2

Equation
› 6CO2 + 6H2O Light C6H12O6 + 6O2

Redox reaction of photosynthesis
› Oxidized:
 H2O to O2
› Reduced:
 CO2 to C6H12O6

Photosynthesis consists of the light
reactions (photo – absorbs light energy)
and the Calvin cycle (synthesis – makes
sugar)
Takes place in the thylakoids
 Split H2O
 Release O2
 Reduce NADP+ to NADPH
 Produce ATP via photophosphorylation
Light Reactions


Calvin Cycle

Takes place in the stroma
Forms sugar using
› CO2 from atmosphere
› ATP and NADPH from light reactions

Starts with carbon fixation
Fig. 10-5-4
CO2
H2O
Light
NADP+
ADP
+ P
i
Light
Reactions
Calvin
Cycle
ATP
NADPH
Chloroplast
O2
[CH2O]
(sugar)