Sunlight energy
Energy Flow and
Matter Cycling
(Carbon)
ECOSYSTEM
Photosynthesis
in chloroplasts
CO2
Glucose
+
+
H2O
O2
Cellular respiration
in mitochondria
ATP
(for cellular work)
Heat energy
Distinguish between autotrophs,
and heterotrophs
• Distinguish between producers,
consumers, and decomposers
Photosynthesis
GENERAL EQUATION FOR
PHOTOSYNTHESIS
Sunlight
6H2O + 6CO2 ----------> C6H12O6+ 6O2
Fig. 7-2a
Leaf Cross Section
Leaf
Mesophyll
Vein
H2O
Chloroplast
CO2 O2 Stoma
Mesophyll Cell
Fig. 7-2b
Chloroplast
Outer and inner
membranes
Thylakoid
Stroma Granum
Thylakoid
space
Intermembrane
space
Pigments
Photosynthesis takes
place in two stages
1) Light reactions
2) Calvin Cycle
Require
Sunlight
Water
Photosynthetic pigments
Photosynthetic pigments are found clustered together in
photosystems (located on the thylakoid membrane)
Photosystems contain
the reaction center
chlorophyll a
primary electron acceptor
other pigments that can transfer absorbed
energy to the reaction center
Where it takes place: Stroma of chloroplasts
What is being used: CO2
ATP
NADPH
What is being produced: G3P (a 3 carbon sugar)
http://www.science.smith.edu/departments/Biology/Bio231/calvin.html
Calvin cycle
CO2
NADPH
3 stages
NADP+
1) Carbon Fixation
2) Production of G3P
3) Regeneration of
starting molecule
ATP
ADP
ATP
ADP
Glucose or Starch
Or cellulose
G3P (a 3 carbon sugar)
CO2 enters the leaf
through the stomata
What would happen under hot dry
conditions?
• Why?
• Effect?
• How do cacti get around this problem?