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CELLULAR RESPIRATION
Definition
Process of releasing energy (catabolism)
stored in molecules to produce ATP which is
used to drive biosynthetic reactions
(anabolism).
CELLULAR RESPIRATION
Energy-Releasing Pathways
Anaerobic
Definition
Energy exchange occurring in the cell
cytoplasm that does not use oxygen as
the final electron acceptor.
Aerobic
Definition
Energy exchange occurring in the
mitochondria using oxygen as the final
electron acceptor.
OXIDATION/REDUCTION
Redox Coenzymes
Reducing NAD+ and FAD
Accept H atoms to become NADH & FADH2
Oxidizing NADH and FADH2
Release H atoms to become NAD+ & FAD
Hydrogen Atoms
Oxidation
Release an electron to become H+
ANAEROBIC CELLULAR RESPIRATION
Glycolysis
Glucose ----> 2 Pyruvate + 2 ATP + 2 NADH
Figure 8.4
ANAEROBIC CELLULAR RESPIRATION
Alcoholic Fermentation
Pyruvate ----> 2 Ethanol + CO2 + 2 ATP
ANAEROBIC CELLULAR RESPIRATION
Lactate Fermentation
Pyruvate ----> 2 Lactate + 2 ATP
ANAEROBIC CELLULAR RESPIRATION
Anaerobic Electron Transport
Sulfates & Nitrogen used as electron acceptors
AEROBIC CELLULAR RESPIRATION
I. Pyruvate/Krebs Cycle Bridge
Pyruvate ----> Acetyl CoA + CO2 + NADH
AEROBIC CELLULAR RESPIRATION
II. Krebs (Citric Acid, TCA) Cycle
Acetyl CoA + Oxalacetate ---->
Citrate + CO2 + NADH + FADH2
Fig. 7.2
AEROBIC CELLULAR RESPIRATION
III. Electron Transport Chain
NADH ----> NAD+ + H+ + eFADH2 ----> FAD + 2H+ + 2e-
AEROBIC CELLULAR RESPIRATION
IV. Chemiosmosis (Electron Transport
Phosphorylation)
ATP Synthase
ADP + Pi ----------------------------> ATP
(H+)
AEROBIC CELLULAR RESPIRATION
V. Final Electron Acceptance
H+ + e- + ½ O2 ----> H2O
CELLULAR RESPIRATION
Final Endproducts
CO2
H2O
ENERGY (100% Potential)
36 ATP or 38 ATP (40%)
ANAEROBIC: 2
AEROBIC:
34 (Skeletal Muscles & Brain)
36 (Liver, Kidneys, Heart)
HEAT (60%)
Unusable energy for the cell
Fig. 7.9
CARBOHYDRATE
CELLULAR RESPIRATION
Glycogen ----> Glucose ----> Pyruvate
Pyruvate
Anaerobic (Possible Pathways)
----> Glycerol
----> Alcohol
----> Lactate
----> Amino Acids
Aerobic (Possible Pathways)
----> Acetyl CoA ---> Krebs Cycle----> Chemiosmosis
----> Fatty Acids ----> Triglycerides
PROTEIN CELLULAR RESPIRATION
Proteins ---> Amino Acids (AA) ----> Deamination (-NH3+)
1)
Amino Acids (Possible Pathways)
a) Pyruvate ----> Glucose
----> Glycerol
----> Acetyl CoA
b) Acetyl CoA ----> FA ---> TG
----> Krebs ---> ETP
c) Oxalacetate ---> Krebs ---> ETP
2) NH3+ ----> Ammonia ----> Urea
LIPIDS CELLULAR RESPIRATION
Triglycerides--> Fatty Acids + Glycerol
1) Fatty Acids ----> Acetyl CoA ---->
Krebs Cycle ----> Chemiosmosis
2) Glycerol----> Pyruvate ----> Glucose
----> Amino Acid
----> Acetyl CoA
ALCOHOL CELLULAR RESPIRATION
Ethanol ---> Acetaldehyde ---> Acetyl CoA
Acetyl CoA ----> Krebs Cycle ----> Chemiosmosis
----> Fatty Acids ----> Triglycerides