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SBI4U: Metabolic Processes
Terms in this set (38)
what are the products of glycolysis for ONE molecule of glucose?
2 net ATP
What are the reactants of glycolysis for ONE molecule of glucose?
2 inorganic phosphates
What are the products of pyruvate oxidation for one molecule of glucose?
What are the products of the KREBS cycle for one molecule of glucose?
What are the major structures (peripheral/integral proteins) involved in the the ETC?
cytochrome b-c complex
How is ATP produced in the cristae (Inner mitochondrial membrane)?
- the electrons from NADH and FADH2 are pumped through complexes, the energy released pumps H+ ions to the intermembrane space
- creates H+ ion gradient and increases proton motor force
- H+ ions move along [ ] gradient through ATP synthase complex into the matrix, creating ATP
The electrons in the ETC are accepted by _____, and form _____
Why is the actual # of ATP produced much lower than 36 or 38?
- Some protons leak through membrane without passing through ATP synthase complex
- ATP used to transport pyruvate from cytoplasm to mitochondria
- Some E used to transport ATP out of mito. for use in cytoplasm
Healthy diet consists of more than just glucose. If you ate something that contained protein (such as Alanine, glutamate), and fats, how would they be used for energy?
-Alanine: converted directed to pyruvate, glutamate can be converted to intermediates in Krebs.
- glycerol: converted to G3P for glycolysis
- fatty acids: transported to mitochondria where carbon atoms are removed in pairs creating Acetyl-CoA
What is the significance of phosphofructokinase?
Feedback control point: when enough ATP is produced, excess ATP binds to allosteric binding site on phosphofructokinase to inhibit enzyme.
- ADP activates this enzyme
Besides ATP, what other molecule can inhibit production of phosphofructokinase?
What inhibits the conversion of pyruvate to Acetyl-CoA?
Explain the process of lactate fermentation.
Glycolysis produces NADH and pyruvate molecules that react with NADH to produce lactate. NAD+ is oxidized, allowing glycolysis to continue.
Explain the process of ethanol fermentation
Glycolysis produces NADH and pyruvate molecules, which get converted to Acetaldehyde. It reacts with NADH to produce ethanol. NAD+ is reoxidized. CO2 is produced.
What is the photosynthesis equation?
6CO2 + 6 H20 + energy --> C6H12O6 + 6O2
_____ 'funnels' light energy to the reaction centre, and is made up of ______.
antenna complex, accessory pigments
Explain the path of electrons starting from photons of light absorbed, to Photosystem II
- photons of light is absorbed by pigment molecule
- antenna complex funnels light energy to the unique chlorophyll a molecules in the reaction centre P680 of photo system II
1NADH yields how many ATP? What about from glycolysis?
3 ATP, otherwise only 2 ATP from glycolysis
1 FADH2 yields how many ATP?
Each time an H+ ion moves in through the ATP synthase from the intermembrane space to the matrix, __________ decreases.
Proton motor force. this is the energy stored in the electrochemical gradient
In the light dependent rxns, ___________ pumps H+ ions into the _________.
b6-f complex, thylakoid space
What happens when light energy is absorbed by photosystem I?
- light E is transferred to rxn centre P700, where e- get excited
- the e- are accepted by e- acceptors, and used by the enzyme NADP reductase to form NADPH.
- NADPH is later used for the light independant rxns.
What is photophosphorylation?
- ATP synthesis using light energy of photos and chemiosmosis
What is non-cyclic phosphorylation?
e- are transferred one direction, from photosystem II to NADP+ to NADPH. (1:1 ratio of ATP and NADPH)
What is cyclic phosphorylation and why is it needed?
- e- from the photosystem I are passed to e- acceptor
- passed back to b6-f complex then back to photosystem I
- same e- is used, yielding only ATP, no NADPH or oxygen
- needed bc more ATP needed for light independant rxn
What are the major structures involved in the light dependant rxns?
P680 rxn centre
P700 rxn centre
Where does carbon get fixed?
in the stroma
Light is required for the light dependent reactions because
A) it is the source for electrons
B) it splits the water molecule
C) it energizes electrons in the reaction center
D) it splits ATP molecules which generates the energy necessary to power the light independent reactions
E) none of the above
In the electron transport chain, H+ ions are pumped through various complexes across the membrane from _____ to _____.
matrix to intermembrane space (IN TO OUT)
In the light dependant rxns, H+ ions are pumped through the B6-f complex from _____ to _____.
stroma to thylakoid space
What is the significance of the nature of the bundle sheath cells for C4 plants?
Bundle sheath are impermeable to CO2, so CO2 is concentrated in these cells making it more efficient
How does the adaptation of C4 plants work?
- In the outer mesophyll cells, CO2 is fixed by adding PEP, creating oxaloacetate.
- This gets converted to malate, which is transported into the bundle sheath cells, which has a high [ ] of Co2
- malate is then decarboxylated (meaning CO2 is RELEASED), resulting in pyruvate which is transported back to mesophyll cells and converted to PEP
- bundle sheath are impermeable to CO2 thus makes calvin cycle more efficient.
What is the name of the first stage of the Calvin Cycle and what happens here?
- CO2 is bonded with a 5C compound RuBP catalyzed by the enzyme rubisco
- forms PGA (3C)
What is the name of the 2nd stage of the Calvin Cycle, and what happens?
- PGA is converted to higher E state, activated by ATP and reduced by NADPH
- forms G3P, and some G3P leave cycle to form glucose (if G3P levels are high, starch is made)
- others move on to replenish RuBP
What is the name of the 3rd stage of the Calvin Cycle and what happens?
- Most G3P are used to regenerate RuBP
- requires ATP
How many times must the Calvin cycle be completed to synthesize ONE glucose molecule? What are the reactants needed?
Name the compounds involved with the Calvin Cycle.
- 6 CO2 reacts with RuBP. This rxn is catalyzed by rubisco
- forms 12 PGA
- 12 ATP and 12 NADPH required to convert to 12 G3P
- 2 G3P used to make glucose, 10 G3P continue on in cycle
- 6 ATP required to convert into 6 molecules of RuBP
What is the full name for RuBP?