Cellular Respiration
Cellular Respiration
OVERALL EQUATION:
C6H12O6(aq) + 6O2(g) -> 6CO2(g) + 6H2O(l)
3 OVERALL GOALS:
1. Break bonds between the 6-carbon molecules of glucose – results in 6 CO2 molecules
2. Move hydrogen atom electrons from glucose to O2, forms 6 H2O molecules
3. Trap as much free energy released as possible in the form of ATP
Stage 1: Glycolysis
Cytoplasm, 10 reactions, anaerobic
Stage 2: Pyruvate Oxidation
Mitochondrial matrix, 1 step process
Stage 3: The Krebs Cycle
Mitochondrial matrix, 8 steps in a cycle
Stage 4: Electron Transport Chain & Chemiosmosis (Oxidative Phosphorylation)
Mitochondrial membrane, various steps
ATP Formation
Substrate Level Phosphorylation:
ATP formed directly
Enzyme-catalyzed reaction
A compound that has phosphate in it, transfers a phosphate group directly to ADP
Forms ATP, fig on pg. 95
Oxidative Phosphorylation:
ATP formed indirectly
Oxidative because it involves redox reactions, with O2 being the last electron acceptor
More complicated than Substrate-Level, but yield more ATP for each glucose molecule processed
NAD+ removes 2 H atoms (2 p+, 2 e-) from original glucose molecule
NAD+ becomes reduced, forming NADH, after attaching 1 p+ and 2 e-
The remaining p+ dissolves into the surrounding solution as H+(aq)
This occurs in one reaction in Glycolysis, during Pyruvate Oxidation & during 3 reactions in the Krebs Cycle
Another coenzyme called FAD performs a similar function
FAD is also reduced by 2 H atoms and is reduced to FADH2 because all of the p+ & e- bind to it
This occurs in one reaction in the Krebs Cycle
The reduction of NAD+ & FAD are energy-harvesting reactions that will eventually transfer free energy to ATP molecules
Glycolysis
Carbon backbone of glucose splits in half, forming two 3-carbon pyruvate molecules
Each step is catalyzed by a specific enzyme
Step One:
ATP phosphorylates glucose to glucose 6-phosphate
Phosphate group is added to glucose by the enzyme Hexokinase
One ATP
OVERALL EQUATION:
C6H12O6(aq) + 6O2(g) -> 6CO2(g) + 6H2O(l)
3 OVERALL GOALS:
1. Break bonds between the 6-carbon molecules of glucose – results in 6 CO2 molecules
2. Move hydrogen atom electrons from glucose to O2, forms 6 H2O molecules
3. Trap as much free energy released as possible in the form of ATP
Stage 1: Glycolysis
Cytoplasm, 10 reactions, anaerobic
Stage 2: Pyruvate Oxidation
Mitochondrial matrix, 1 step process
Stage 3: The Krebs Cycle
Mitochondrial matrix, 8 steps in a cycle
Stage 4: Electron Transport Chain & Chemiosmosis (Oxidative Phosphorylation)
Mitochondrial membrane, various steps
ATP Formation
Substrate Level Phosphorylation:
ATP formed directly
Enzyme-catalyzed reaction
A compound that has phosphate in it, transfers a phosphate group directly to ADP
Forms ATP, fig on pg. 95
Oxidative Phosphorylation:
ATP formed indirectly
Oxidative because it involves redox reactions, with O2 being the last electron acceptor
More complicated than Substrate-Level, but yield more ATP for each glucose molecule processed
NAD+ removes 2 H atoms (2 p+, 2 e-) from original glucose molecule
NAD+ becomes reduced, forming NADH, after attaching 1 p+ and 2 e-
The remaining p+ dissolves into the surrounding solution as H+(aq)
This occurs in one reaction in Glycolysis, during Pyruvate Oxidation & during 3 reactions in the Krebs Cycle
Another coenzyme called FAD performs a similar function
FAD is also reduced by 2 H atoms and is reduced to FADH2 because all of the p+ & e- bind to it
This occurs in one reaction in the Krebs Cycle
The reduction of NAD+ & FAD are energy-harvesting reactions that will eventually transfer free energy to ATP molecules
Glycolysis
Carbon backbone of glucose splits in half, forming two 3-carbon pyruvate molecules
Each step is catalyzed by a specific enzyme
Step One:
ATP phosphorylates glucose to glucose 6-phosphate
Phosphate group is added to glucose by the enzyme Hexokinase
One ATP