CH10 Photosynthesis Flashcards
Photosynthesis
Converts light energy to chemical energy
Site of Photosynthesis
Chloroplast
Leave green pigment
Chlorophyll
Pores for gas exchange
Stomata
Photosynthesis Reaction
6 CO2 + 6H2O —> C6H12O6 + 6 O2
Splitting of Water=
2H2O —-> 4H+ + 4e- + 6O2
Photo. Redox
CO2 is reduced
H2O is oxidized
steps of PSYN.
- light Reactions
- Calvin Cycle (synthesis)
- Gluconeogenesis (also synthesis)
Light RXN’s happen in…
Thylakoids
Dark RXN’s happen in …
Stroma
Nature of Sunlight
Light is a form of electromagnetic energy (EM Radiation)
Electromagnestic Spectrum
entire range of EM energy
Light colors which drive PSYN
Red and Blue
Pigments function
Absorb Light for PSYN
2 major pigments
Chlorophyll ALPHA and beta
Carotenoids
absord excessive light which would damage chlorophyll
Photosystem
Light Harvesting complexes
PS II
Absorbs blue light P680
strong oxidizing agent
PS I
Absorbs red light (P700)
Carbon In Calvin Cycle
- CO2 enters and leaves as organic acid (called G3P)
Gluconeogenesis
2G3P used to make Glucose
Glucose uses
- Glucose cannot accumulate;
1. Sucrose
2. Starch (storage)
3. Cellulose (structure)
C3 Plants
Plants use rubisco & have to close stoma on hot days
Dehydration occurs
C4 Plants
_tropical grasses etc.
- uses PEP carboxylase (higher affinity for CO2)
- Avoids Rubisco
- SPATIAL DIFFERENCE
CAM Plants
- ie. Cactus etc.
- Stomata only open at night
- TEMPORAL DIFFERENCE
