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Where do materials come from? What are they/
- Come from Krebs/TCA cycle and glycolysis
- They are metabolic intermediates
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
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
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)
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!*
What is the 3rd step of Carbon Fixation?
- Regeneration of ribulose bisphosphate-Glucose is made
- -6 glucoses made - each glucose comes from 6CO2 molecules
Why fix Nitrogen?
Needed to make proteins
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)
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*
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