Cellular Respiration Flashcards
What kind of process is cellular respiration?
Exergonic
What kind of process is photosynthesis?
Endergonic
Aerobic Respiration
consumes oxygen as a reactant
Anaerobic respiration
replaces oxygen with another inorganic molecule
General formula of cellular respiration
C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP
Oxidation
The loss of electrons
Reduction
The gain of electrons
Reducing agent
Electron donor
Oxidizing agent
Electron acceptor
Electron carrier used in cellular respiration
NAD+, NADH
Dehydrogenases
- Enzymes that transfer 2 electrons and a proton from an organic compound to NAD+
- This produces NADH
Substrate-level phosphorylation
- Process by which a phosphate is attached to an organic molecule is passed onto another molecule without the use of an electron transport chain
- Formation of ATP
Glycolysis
- Breakdown of glucose into 2 pyruvate molecules
- Takes place in the cytoplasm (no oxygen)
Two major phases of glycolysis
- Energy investment phase
- Energy payoff phase
Glycolysis general formula
Glucose + 2NAD+ + 2ADP + 2phosphates -> 2ATP + 2NADH + 2H+ +2H2O + 2pyruvate
Pyruvate oxidation
- Begin with pyruvate (3 carbons) which undergoes changes to become acetyl (2 carbons)
1. Decarboxylation (-CO2)
2. Oxidation by NAD+
3. Co-enzyme A attaches to acetyl
Pyruvate oxidation formula per 1 pyruvate
pyruvate + NAD+ + CoA -> NADH + H+ + CO2 + acetyl-CoA
Pyruvate oxidation formula per glucose
2pyruvate + 2NAD+ + 2CoA -> 2NADH + 2H+ + 2CO2 + 2acetyl-CoA
What step does the kerb’s cycle start and end with?
oxaloacetate
Kreb’s Cycle
- Oxaloacetate (4 carbons) attaches to acetyl (2 carbons) this triggers the beginning of the Kreb’s Cycle
- 2 cycles per glucose
- By the end of the cycle all carbons from glucose are oxidized and have been removed as CO2
Kreb’s cycle formula per acetyl-CoA
acetyl-CoA + 3NAD+ + FAD + ADP + phosphate + H2O -> ATP + FADH2 +3NADH + H+ + 2CO2 + CoA
Kreb’s cycle formula per glucose
2acetyl-CoA + 6NAD+ +2FAD +2ADP + 2phosphate + 2H2O -> 2ATP + 2FADH2 + 6NADH + 2H+ + 4CO2 + 2CoA
Oxidative phosphorylation
The synthesis of ATP through the energy released by the transfer of electrons using an electron transport chain and chemiosmosis
Electron Transport Chain
- Involves several membrane bound proteins and active molecules
- Pumps 3H+’s per NADH
- Pumps 2H+’s per FADH2
What starts the electron transport chain?
- NADH + H+ gets oxidized to NAD+
What is O2 in the ETC
- “ultimate electron acceptor”
- because of it’s high electronegativity
What is H2O in the ETC?
The last molecule that contains glucose’s electrons
Chemiosmosis
- Creates an electrochemical or proton gradient which motivates H+ to re-enter the matrix through ATP synthase
- The electrochemical gradient creates a “proton motive force” which moves H+ ions
How does chemiosmosis work?
- H+ ions are pumped through ATP Synthase
- Causes ADP + Pi to react and form ATP
- 4 protons per 1 ATP molecule
How much ATP is made from cellular respiration?
30 or 32 ATP depending on which NADH shunt is used
Phosphofructokinase
Enzyme in glycolysis that regulates the rate at which glucose is broken down
