1
Q
glycolysis
A
- in the cytoplasm of the cell
- anaerobic process
- phosphorylation : 2P from ATP attach to glucose
- forms hexose bisphosphate
- lysis : destabilises mol
- splits into 2x triose phosphates
- P (from free inorganic P ions) added to each triose
- forms 2x triose bisphosphate
- triose bisphosphate oxidised by dehydrogenation (removal of H atoms)
- 4x ATP formed using P from TBP
- forms 2x pyruvate
- NAD coenzymes accept removed H atoms
- forming 2x reduced NAD
- net yield : 2 ATP mol
2
Q
what is substrate level phosphorylation
A
- formation of ATP
- without involvement of ETC
- formed by transfer of a P group to ADP
3
Q
the link reaction
A
- pyruvate enters mitochondrial matrix
- active transport
- via specific carrier proteins
- pyruvate undergoes oxidative decarboxylation - CO2 + H removed
- H accepted by NAD
- reduced to form NADH
- 2c acetyl groups bound to coenzyme A
- forms acetyl CoA
- acetyl CoA delivers the acetyl group to the next stage = krebs cycle
- CO2 produced diffuse/removal of metabolic waste/photosynthesis
4
Q
krebs cycle
A
- mitochondrial matrix
- acetyl CoA delivers acetyl group to krebs cycle
- 2c acetyl combines with 4c oxaloacetate
- forms 6c citrate
- citrate = decarboxylation + dehydrogenation
- forms reduced NAD + CO2
- forms 5c compound
- 5c= decarboxylation + dehydrogenation
- regenerates oxaloacetate
- ATP from substrate level phosphorylation
- cycle continues
5
Q
oxidative phosphorylation
A
- inner mitochondrial membrane
- membrane folded = cristae = inc SA = max resp
- H released from reduced NAD/FAD when oxidised
- H dissociate into H+ +e-
- e- into ETC
- energy released pumps H+ from mitochondrial matrix to intermembrane space
- H+ move down ECG back into MM via ATP synthase
- energy released synthesises ATP
- at end of ETC, 2(e-) + 2(H+) + (1/2O2) = water
- O2 = final electron acceptor
- ETC can’t operate unless O2 present
6
Q
net products for one mol of pyruvate in krebs cycle
A
3xR NAD
1x R FAD
2x CO2
1x ATP
7
Q
fermentation
A
- anaerobic
- no O2
- substrate level phosphorylation
8
Q
alcoholic fermentation
A
- ethanol + CO2
- in yeast and some plant root cells ^
- pyruvate converted into ethanal
- catalysed by pyruvate decarboxylase
- ethanal accepts H from RNAD
- ethanol
- regenerated NAD still a Co
- glycolysis continues
- ethanol toxic waste product
9
Q
lactate fermentation in mammals
A
- produces lactate
- pyruvate can take H from RNAD
- catalysed by lactate dehydrogenase
- pyruvate converted to lactic acid
- regenerated NAD allowing glycolysis to continue
- LA converted back to glucose in the liver but O2 is needed
- can cause O2 debt
- LA removed from muscles and to the liver in bloodstream
- lactic acid recycled as glucose
10
Q
carb, protein , lipid RQ
A
carb : 1.0
proteins : 0.9
lipid : 0.7
11
Q
RQ
A
co2 released / O2 taken in
- measured using respirometer
