Photosynthesis
-
Upload
erica-spoerri -
Category
Business
-
view
1.038 -
download
0
Transcript of Photosynthesis
Photosynthesis
The process in which light energy is transformed into chemical energy
Performed by Producers such as Plants Algae some Protists (eg:
Phytoplankton)
It is a complex series of reactions that can be summarised as:
6CO2 + 6H2O C6H12O6 + 6O2
or
6CO2 + 12H2O C6H12O6 + 6O2 + 6H2O
Photosynthesis Overview6H2O + 6 CO2 --> C6H12O6 + 6 O2
Light Dependent StageH2O --> O2
requires Light E
Light Independent StageCO2 --> 2x3C sugars
ChloroplastsFlat shape provides a large surface
area exposed to sunlightMany stomata on one or both leaf
surfaces provides access to CO2
Thinness and presence of air spaces in leaves enable diffusion
Xylem vessels transports water to cells
Many chloroplasts to trap lots of energy
Draw and label chloroplast
Light-dependent stageOccurs in GranaNeeds water and light energye- that is absorbed is used to:
◦Produce ATP◦Split H20 molecules (2H+ and O)
NADP is a carrier/acceptor molecule that gathers H+ ions
ATP and NADPH are used in next stage (light-independent stage)
Inputs Outputs
Water H2O ATP
Electron e- NADPH
NADP+
ADP + POxygen (“waste”)
Light-independent stageOccurs in StromaDoes not need light but NADPH and
ATP from previous stageNeeds CO2 and H+ ions Sugar molecules are synthesised from
CO2
CO2 = oxidised state (low E compound)
C(H2O)n = reduced state (high E compound)
NADPH (carrier H+) is the reducing agentATP is the energy source
Inputs Outputs
ATP ADP + P
NADPH NADP+
CO2 3C (PGAL) -> Glucose
Carbon reduction in C3 Plants
Calvin Cycle
=PGAL
Carbon reduction in C4 plantsPlants in hot,
dry habitats and important crop plants such as corn, sugar cane
One step before Calvin cycle:
Putting Photosynthesis together