Photosynthesis Flashcards
What carries out photosynthesis?
- Plants
- Algae
- Prokaryotes
Photosynthesis
Process where sunlight is converted into chemical energy in the form of carbohydrates
2 stages of photosynthesis
- Light Reactions
- Calvin Cycle
Photosynthesis general formula
Energy + 6CO2 + 6H2O –> C6H12O6 + 6O2
What kind of process is photosynthesis?
Endergonic and requires energy that comes from sunlight
Photon
A discrete quantity of light with a specific quantity of energy
Electromagnetic Spectrum
Entire range of electromagnetic energy
Pigments
Substances that absorb visible light of specific wavelengths
Absorption Spectrum
Graph showing the ability of a pigment to absorb different wavelengths of light
Where are pigments found?
In thylakoid membranes
Chlorophyll a
Primary light-capturing pigment
Chlorophyll b
Accessory pigment that works in conjunction with chlorophyll a
Carotenoids
Accessory pigments that broaden the spectrum of light that can drive photosynthesis
Where do the light reactions occur?
Thylakoid membranes
Light Reactions
- Supply energy needed to drive the Calvin Cycle
- Transfer electrons and protons from water to NADP+ forming NADPH
- Produces ATP through an electron transport chain and chemiosmosis
Photophosphorylation
The eventual production of ATP using light energy
Photosystems
- Captures solar energy
- Contains photosynthetic pigments
- 2 types of photosystems (II and I)
How is solar energy captured?
By exciting electrons to a higher orbital
Linear Electron Flow
Makes ATP and NADPH that can be used in the Calvin cycle
Light Reaction Equation
1H2O + 1.5ADP + 1.5phosphate + 1NADP+ + light -> 0.5O2 +1.5ATP + 1NADPH + H+
Calvin Cycle
- Chemical energy from the light reactions are now used to produce the sugar G3P
- Uses ATP and NADPH to generate sugar
G3P
After three turns of the Calvin cycle one G3P molecule is made
Carbon Fixation
- CO2 enters from the atomosphere
- Process where CO2 bonds with the first compound in the Calvin cycle
- mediated by enzyme rubisco
Calvin Cycle Equation
3CO2 + 6NADPH + 9ATP + 5H2O -> 1G3P + 6NADP+ + 9ADP + 8phosphate + 2H+
