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Bio Ch 7 Photosynthesis - Coggle Diagram
Bio Ch 7 Photosynthesis
Autotrophs
- organisms that can capture energy and synthesize organic molecules from inorganic molecules
- they produce their own food
- plants algae, cyanobacteria
Heterotrophs
- organisms that are unable to produce their own food
- must consume autotrophs as a source of food
- plants also release O2 as a bi-product of photosynthesis
- we use O2 in cellular resp.
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Photosynthesis
- light energy is used to create ATP
- ATP provides energy needed to reduce O2 into glucose
- CO2 reduction needs electrons
- light doesnt have electrons and H ions
- light energy is also used to create NADPH
- NADPH can provide electrons and H ions
Two Stages
Light reactions
- the portion of photosyn. that captures solar energy
Calvin Cycle (dark)
- the portion of photosyn. that takes place in the stroma of chloroplasts
- uses the product of the light reactions to reduce CO2, to glucose
Summary
- capture energy from sunlight
- using captured light energy to produce ATP and NADPH (light reactions)
- Solar energy --> chemical energy (ATP and NADPH)
- using ATP and NADPH to make glucose from CO2 in the atmosphere (calvin cycle-dark reactions)
- Chemical energy --> chemical energy (glucose)
Light Reactions
- occurs in the Thylakoid membrane
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- pigments can act as an antenna to capture energy from sunlight
The ETC
- the movement of energized electron powers a proton pump which pushed H+ ions into the Thylakoid space
- travel through protein channel called ATP Synthase
- as protons diffuse back (high --> low) and pass through ATP synthase ADP is phosphorylated into ATP in a process called chemiosmosis
The Calvin Cycle
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- takes place in the stroma of the chloroplast outside the Thylakoids
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- the CC uses ATP and NADPH from the light reactions in carbon diox. fixation
- when plants and other autotrophs convert CO2 gas into a carb, we call this "fixing"
THREE STEPS
- Carbon Dioxide fixation
- Carbon dioxide reduction
- Regeneration of RuBP
STEP 1
- molecule of CO2 is attached to a 5-carbon RuBP
- new 6-carbon molecule splits into a two 3-carbon molecules (3-PG)
- to fix the CO2 to the RuBP, we need Rubisco (enzyme)
STEP 2
- the two 3-PG molecules undergo reduction to G3P (glyceraldehyde-3-phosphate)
- this takes 2 steps
- ATP turns into ADP + P and NADPH turns into NADP +
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