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Photosynthesis
● What is photosynthesis and respiration? ● How do plants survive and support a whole ecosystem in
the Arctic Ocean? ● Why are plants green?● How did photosynthesis evolve?● How do plants convert light into chemical energy?
Photosynthesis uses sunlight as energy to make biomass from CO2
Respiration uses oxygen to consume biomass and release CO2
Half of biomass is produced on land and half is produced in the ocean.
Microscopic algae of the Ocean: Diatoms!
● Melosira Arctica●
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● meters long chains of individuals cells
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Photosynthesis under ice
Photosynthesis underneath multiyear ice
Snow Covering IceSunlightAbundance of tiny green plants
Seasons of the Year (NovemberOctober)
Real Scientists at UW
Walrus dive to the bottom for food.
Temperature is rising globally.
Photosynthesizers weren't (aren't) always green...
Purple Sulfur bacteria
All plants and algae contain chloroplasts.
Most scientists believe that chloroplasts evolved from symbiotic green bacteria
Lynn Margulis
2H2O > 4e− + 4H+ + O2
How do plants convert light to chemical energy?
2H2O > 2H2 + O2, G = +118 kcal.Δ
As written, does this reaction proceed forwards or backwards?
1 calorie = 4.18400 joule
How many KJ is this?
How do plants convert light to chemical energy?
Hydrogen fuel
Why are plants green?
Chlorophyll molecules in the chloroplast absorb light and send the light energy to a reaction center.
All plants and algae contain chloroplasts.
Most scientists believe that chloroplasts evolved from symbiotic green bacteria