i. overview of photosynthesis l06: photosynthesis ... p&r... · l06: photosynthesis &...
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2/3/20
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L06: Photosynthesis & Respiration
BIOL 153/LBlack Hills State Univ.Ramseys
I. Overview of photosynthesis
A. Chemical formula
CO2 + H2O + Energy => C6H12O6 + O2
input output
B. Chloroplast
See lecture'Chloroplast Origins'
1. Pigments
chlorophyll + carotenoids
2. Membranes
inner/outer + thylakoid membranes
3. Electrons
photosystem ETS
4. Chemical bonds
carbohydrates assembled
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C. Action spectrum 1. Types of electromagnetic radiation
1. Types of electromagnetic radiation 2. Wavelengths used by plants
blue light: ~400 - 500 nm
red light: ~600 - 700 nm
2. Wavelengths used by plants
why are plants green?
D. Biochemical pathways
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1. Light reactions
light energy converted to ATP + NADPH
2. Dark Reactions
ATP + NADPH assembles carbohydrates
II. Overview of respiration
A. Chemical formula
C6H12O6 + O2 => CO2 + H2O + Energy
input output
B. Mitochondria
See lecture'Origin of Chloroplasts'
1. Membranes
inner/outer membranes (cristae)
2. Electrons
respiration ETS
3. Chemical bonds
Carbohydrates disassembled
See lecture'Origin of Chloroplasts'
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C. Biochemical pathways 1. Aerobic (high ATP yield)
Glycolysis => Respiration(cytosol) (mitochondria)
2. Anaerobic (low ATP yield)
Glycolysis => Fermentation(cytosol) (cytosol)
III. P&R as opposing biochem forces
ouput of photosynthesis = input for respiration(and vice versa)
Fig. 6-5Raven p. 95
IV. Measurement of P&R
super insightful!
organic molecules made (P)
minus
organic molecules burned (R)
• Option #1: Biomass
terrestrial:straightforward
aquatic:straightforward
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• Option #2: Gas exchange
O2 produced (P)
or
CO2 produced (R)
terrestrial:challenging
aquatic:straightforward
leaf disk
water column
Leaf disk assay
Scenario #1: P > R
• more O2 made vs. consumed
• O2 accumulates in leaf
• bouyant bubbles
• leaf floats
Scenario #2: R > P
• more O2 consumed vs. made
• O2 disappears in leaf
• no bouyount bubbles
• leaf drops
V. Terrestrial consequences of P&R
photosynthetic organisms transformed earth(geological time)
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VI. Aquatic consequences of P&R
photosynthetic organisms transform water bodies(daily + seasonally)
Waves (lake surface)
A. Sources of oxygen
• Atmosphere
• Small photosynthetic plankton: P
• Large photosynthetic plants: P
B. Sources of carbon dioxide
• Decomposition
• Heterotrophic organisms: R
• Photosynthetic organisms: R
C. Changes through day
Summer (Day) Summer (Night)
Wind
Waves (lake surface)
Phyto-plankton
Wind
Waves (lake surface)
Summer (Day) Summer (Night)
Wind
Waves (lake surface)
Phyto-plankton
High O2
Wind
Waves (lake surface)
High CO2
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D. Changes through seasons
Summer (Day) Winter (Day)
Wind
Waves (lake surface) Ice
Snow
Phyto-plankton
Summer (Day) Winter (Day)
Wind
Waves (lake surface) Ice
Snow
Phyto-plankton
High O2
Low O2 Min O2
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