1. Bio 178 Lecture 15 Cellular Respiration

2. ? Reading Quiz Material Chapter 9 Questions on P 184
Chapter 9 Quizzes on Text Website (

3. Outline
Cellular Respiration
Glucose catabolism

4. ATP Synthase

5. Glucose Catabolism Methods for Making ATP
1. Substrate-Level Phosphorylation
ADP + Pi  ATP
Pi comes from a phosphate-bearing intermediate molecule.
Example - Glycolysis.
2. Aerobic Respiration
ATP synthase makes ATP using energy provided by electron transfer. O2 = final electron acceptor.

6. Substrate-Level Phosphorylation

7. Aerobic Respiration

8. Processes Involved in Eukaryotic Respiration
1. Glycolysis
Sugar splitting anaerobic process.
Location
Cytoplasm
Energetic Products
2 ATP net & 2 NADH net produced by substrate level phosphorylation.
2. Aerobic Respiration
Pyruvate oxidation
Krebs cycle
Electron transport chain

9. Glycolysis 1. Glucose Priming 2. Cleavage 3. Energy Harvesting
Glucose + 2 ADP + 2 Pi + 2 NAD+  2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O
10 enzyme catalyzed steps can be divided up into 3 major stages:
1. Glucose Priming
Glucose is prepared for cleavage using 2 ATP.
2. Cleavage
Fructose 1,6-bisphosphate (6C)  2 X 3C molecules.
3. Energy Harvesting
The 2 X 3C molecules are converted into 2 pyruvate (3C), releasing 2 NADH and 4 ATP by substrate-level phosphorylation.

10. Principle Stages of Glycolysis

11. Glycolysis Pathway

12. Glycolysis Pathway

13. Glycolysis (Cntd.) Bookkeeping NAD+ Regeneration 1. ATP
4 ATP - 2 ATP = 2 ATPnet
2. NADH
2 NADH
NAD+ Regeneration
Glycolysis depletes cellular NAD+ stores. The cell uses 2 methods to recycle NAD+ (transfer electrons and H+):
Aerobic respiration
Fermentation

14. Pyruvate Fate

15. Allows glycolysis to continue in the continued presence of glucose.
Fermentation
Allows glycolysis to continue in the continued presence of glucose.
2 types:
Ethanol - Yeast
2 Pyruvate (3C)  2 Acetaldhyde (2C) + 2 CO2  2 Ethanol (2C) (+ 2 NAD+)
Toxic to yeast at 12%
Lactic Acid - Animals
2 Pyruvate (3C)  2 Lactate (3C) (+ 2 NAD+)
When lactate is produced faster than it is removed  Muscle fatigue

16. Fermentation

17. Acetyl-CoA Production
Function
Oxidation of pyruvate to produce NADH
Acetyl-CoA used either in fat synthesis or ATP generation
Overall Reaction
Pyruvate (3C) + CoA + NAD+  Acetyl-CoA (2C) + CO2 + NADH
Catalyzed by pyruvate dehydrogenase
Coenzyme A is a cofactor
Location
Pyruvate is shuffled into the mitochondrion. Acetyl co-A is made in the mitochondrial matrix.