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acr review Cheat Sheet by

intro to acr, mitochondrial structure, ins and outs of acr, general reactions, efficiency of acr

cellular respir­ation overview

synthesize ATP (i.e. energy)
glycol­ysis, pyruvate oxidation, krebs/­citric acid cycle, electron transport/ oxidative phosph­ory­lation
C6H12O6 + 6 O2 + 36 ADP → 6 CO2 + 6 H2O+ 36 ATP

mitoch­ondrial structure

do you know what the powerhouse of the cell is called

ins and outs

in - 1 glucose, 2 NAD, 2 ATP, 4 ADP
out - 2 pyruvate, 2 NADH, 2 ATP (two consumed in phase one, four produced in phase two)
pyruvate oxidation
in - 1 pyruvate, 1 NAD
out - 1 acetyl­-CoA, 1 NADH, 1 CO2
krebs/­citric acid cycle
in - 1 acetyl­-CoA, 3 NAD, 1 FADH, 1 ADP
out - 1 CoA (acety­l-CoA -> citric acid -> oxaloa­cetate; oxaloa­cetate reacts with another acetyl-CoA to form citric acid and repeat cycle), 3 NADH, 1 FADH, 1 ATP, 2 H2O, 1 CO2
for pyruvate oxidation and krebs cycle, the total number of products should be multiplied by two in order to calculate the number of products per glucose molecules because each process occurs once for each pyruvate formed in glycolysis

ATP structure

ATP consists of three phosphate groups, a five carbon sugar, and a nitrog­enous base. The nature of this molecule is very unstable due to the negative charge of the three phosphate groups; the phosphates naturally want to break away from each other. When ATP is consumed for energy, the bond between the second and third phosphate are broken. This energy can then be used to power other (ender­gonic) reactions within the cell.

general reactions in CR

phosphate group is transf­erred
molecule is struct­urally rearranged
molecule is split into two
krebs cycle
carboxyl group is removed from molecule; CO2 is produced
in glycolysis and krebs cycle, the type of phosph­ory­lation that occurs is substr­ate­-level. substr­ate­-level phosph­ory­lation occurs when a phosphate group is directly transf­erred from a substrate to another molecule. the other kind of phosph­ory­lation, i.e. oxidative phosph­ory­lation, is when a series of redox reactions leads to a final electron acceptor. this mode of phosph­ory­lation occurs in the electron transp­ort­ation.

electron transport chain

create a proton gradient by moving hydrogen ions from the mitoch­ondrial matrix to the interm­embrane space to drive ATP synthesis
protein complexes
four protein complexes
complex 3 collects electrons from complexes 1 & 2; complex 4 collects electrons from complex 3
electron shuttles
NAD(H): NAD is reduced to NADH in previous stages of CR; delivers electrons to complex 1 & 2
FAD(H2): FAD is reduced to FADH2 in previous stages of CR; delivers electrons to complex 2
UQ (ubiqu­inone): shuttles electrons from complexes 1 & 2 to complex 3
Cyt-c (cytoc­hro­me-c): shuttles electrons from complex 3 to 4
FADH2 bypasses protein complex 1 because the electrons exist on an energy level that is too low for complex 1 to pick up on
energy from electrons is used to drive protein complexes; complexes pump hydrogen ions into the interm­embrane space
ATP synthase enzyme pumps one hydrogen ion back into the matrix to synthesize ATP (combines ADP and inorganic phosphate)


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