Chapter 4 - Metabolism and Energy Flashcards
Purpose of Cellular Respiration
to convert energy within glucose to energy that does work in a cell in the form of ATP
Four Steps of Cellular Respiration
- Glycolysis
- Pyruvate Oxidation
- Citric Acid Cycle
- Oxidative Phosphorylation
Location of Steps
- Glycolysis - Cytosol
- Krebs Cycle - Mitochondrial matrix
- Electron Transport Chain - Inner mitochondrial membrane
- Fermentation - Cytosol
Inner Membrane
→increases surface area where respiratory processes take place, site of ETC and ATP production
Cristae
infoldings of inner membrane, increases SA for oxid phosphorylation (ETC)
Matrix
space inside inner membrane, filled with enzymes, where Krebs, PO take place
Evidence of Endosymbiosis
own DNA, double membrane
Substrate Level Phosphorylation
ATP is formed directly from the enzyme controlled reaction (in glycolysis and krebs), phosphate group is transferred from one molecule to an ADP molecule
Oxidative Phosphorylation
ATP is formed indirectly from a series of redox reactions, oxygen is the final electron acceptor, carried out by NADH and FADH2 (cofactors)
Glycolysis
- Cytosol
- Anaerobic
COnverts glucose (6C) into pyruvate (3C) ENZYME CATALYZED
Glycolysis Reactants
- glucose
- 2 NAD+
- 2 ATP
Glycolysis Products
- 2 pyruvate molecules
- 2 ATP (net gain)
- 2 NADH
Energy Investment Phase
2 ATP consumption, phosphorylation of glucose
Energy Payoff Phase
production of 4 ATP and 2 NADH
Substrate Level Phosphorylation
ADP –> ATP
Isomerization
The rearrangement of atoms within a molecule
Oxygen is Present
the hydrogen acceptors and pyruvate continue to Krebs (aerobic)
Insufficient Oxygen
pyruvate stays in cytoplasm and gets converted to lactic acid or ethanol (fermentation)
Link Reaction
- pyruvate (3C) converted into Acetyl CoA (2C)
- release of CO2 and reduction of NAD+
Reactants - Pyruvate Oxidation
- 2 pyruvate
- 2 NAD+
- 2 coenzyme A (CoA)
Products - Pyruvate Oxidation
- acetyl-CoA
- 2 NADH (goes to ETC)
- 2 CO2
Coenzyme A
A carrier that helps enzymes hold and modify molecules
- CoASH - unbonded
- -CoA - bonded
Decarboxylation
The removal of a carboxyl group from a molecule
- CO2 released - waste
Krebs Cycle
Krebs only occurs when oxygen is present
Reactants - Krebs Cycle
- 2 acetyl - CoA
- 6 NAD+
- 2 FAD
- 2 H2O
- 2 ATP
Products - Krebs Cycle
- 6 NADH
- 2 FADH2
- 2 ATP
- 4 CO2
- 2 CoASH
Oxaloacetate
- acts as a product and reactant
- combines with acetyl group
- releases CoA
- Converted to Citrate (citric acid)
GDP –> GTP
substrate level phosphorylation
- used to produce ATP
