1. Cellular Respiration

2. Mitochondria Many in active cells such as muscle
Double membrane (inner and outer)
Inner membrane is folded
Folds = more surface area

3. Oxygen determines outcome
Aerobic
With oxygen
Makes more energy
Anaerobic
Without oxygen
Less effective
Not sustainable
Fermentation

4. Glucose Monosaccharide carbohydrate
Stored in animals as glycogen (starch in plants)
During digestion, many compounds are converted to glucose for cell use
Source of energy, but not usable by cell organelles, must be converted to ATP

5. Overview

6. Steps to respiration Glycolysis Krebs or Citric Acid Cycle
Formation of Acetyl CoA
Krebs or Citric Acid Cycle
Electron Transport Chain (ETC)

7. Glycolysis Occurs in cytoplasm Break glucose in half  pyruvic acid
Uses 2 ATP, releases 4 ATP produced: Net 2 ATP
NAD+ (nicotinamide adenine dinucleotide) accepts electrons to become NADH (helps carry energy from glucose to other pathways)

8. Inside the mitochondria
A. Formation of acetyl CoA B. Krebs cycle C. Electron transport chain

9. A. Formation of Acetyl-CoA
Pyruvate is split to form CO2 and acetyl group.
Acetyl group attaches to coenzyme A to form acetyl CoA
NAD+ takes electrons to make NADH
Acetyl CoA to Krebs

10. B. Kreb’s Cycle/Citric Acid Cycle
Acetyl CoA to citric acid
Cycle proceeds
Total summary:
4 CO2
2 ATP
6 NADH
2 FADH2

11. C. Electron Transport Chain

13. ETC Inner membrane of mitochondria
High energy electrons from NADH and FADH2
Enzymes at the end combine electrons with hydrogen ions and oxygen to form water (oxygen is final electron acceptor)
Electron energy pumps H+ ions in
ATP synthase uses gradient to produce ATP

14. Alternate Pathway: Fermentation
Required to turn NADH from glycolysis back to NAD+ to keep process going (normal it goes to ETC)
Can keep glycolysis going, but does not fully use energy of glucose and is less efficient than aerobic respiration
Lactic acid: pyruvate to lactate (yogurt, sour cream, and cheese! YUM)
Alcoholic fermentation: pyruvate to ethanol and CO2, yeast