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Where do materials come from? What are they/
- Come from Krebs/TCA cycle and glycolysis
- They are metabolic intermediates
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CO2/Carbon Fixation - What is it? What is primary source? What is main enzyme involved?
- Carbon fixation - conversion of carbon dioxide into organic compounds
- Primary source - Cyanobacteria
- Main enzyme - RuBisCO = Ribulose Bisphosphate CO2 oxidase
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What is the Calvin Cycle? What are the 3 steps?
- Calvin Cycle - energy from light is used to convert CO2 and water into organic compounds which store chemical energy
- 3 steps - Carboxylation, Reduction, Fixation
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What occurs during the first step of Carbon Fixation?
- CarboxylationReaction catalyzed by RuBisCO1.) Rubisco adds co2 to pentosbisphosphate (5C -->6C)
- 2.) water is added and 6C--> 2x3C (3-p-glycerate)
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What occurs in the second step of Carbon Fixation?
- Reduction1.) 3-p-glycerate phosphorylated to 1,3-bis-p-glycerate (uses 1 ATP/3-P-glycerate)2.) NADPH reduces 1,3-bis-p-glycerate, a Pi is lost and glyceraldehyde-3-P is product
- *ATP and NADPH are used - energy is consumed!*
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What is the 3rd step of Carbon Fixation?
- Regeneration of ribulose bisphosphate-Glucose is made
- -6 glucoses made - each glucose comes from 6CO2 molecules
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Why fix Nitrogen?
Needed to make proteins
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What is the enzyme that fixed Nitrogen? What are the compentents? What is it's role? What does it need (2)?
- NitrogenaseMolybdenum attached to Fe-S cluster
- Transfers e-
- Donor and anearobic conditions (O2 will reduce)
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Explain Nitrogen Fixation. Rounds, Electron donor, How much ATP is used/why
- ATP is used to bind substrate (16/N2)
- NADH donates e- (8/N2) which are used 2 at a time to reduce each N by 1
- *N2 has 3 bonds, so it gets reduced 4 times to make 2NH4+ 2 e- each reduction and 4 ATP*
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Nitrogen assimilation - What is it? What happens? What is transamination?
- Incorporation of NH4+ into amino acids
- alpha - ketoglutamate + NH4+ gives glutamine
- Transamination - Glutamine donates NH3 to make other Amino Acids
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