1. Cellular Respiration

2. Overview

3. Organic Compounds Glycolysis Oxygen present Aerobic Respiration ATP
Oxygen Absent
Fermentation

4. Glycolysis
1 6-C molecule is oxidized to produce 2 3-C molecules of Pyruvic Acid
All reactions take place in the cytosol of the cell
Has a net yield of 2 ATP molecules for every glucose converted to pyruvic acid

5. Fermentation DOES NOT PRODUCE ATP NO OXYGEN Regenerates NAD+
2 common Pathways
Lactic Acid
Ethyl Alcohol
NAD+ used to keep glycolysis going to produce ATP

6. LACTIC ACID
Pyruvic Acid converted into another 3-C compound (lactic Acid)
Involves the transfer of 2H atoms from NADH and H+ to pyruvic acid
Plays a major role in manufacturing food products
Occurs in muscles during strenuous exercise
Eventually LA will be transported back to liver where converted back to pyruvic acid
NADH is oxidized to NAD+---then used in glcolysis ---reduced to NADH
Food products such as yogurt and cheese

7. ALCOHOLIC FERMENTATION
Yeast cells are added
2 step pathway
CO2 molecule is removed from pyruic acid
Leaves a 2-C compound
2H atoms are added to the 2-C compound to make ethyl alcohol
H atoms come from NADH &H+ regenerating NAD+
Basis for wine beer and bread production
Bread can release O2

8. Energy yield Complete oxidation of glucose releases 686 kcal
How efficient are the anaerobic pathways at obtaining energy from glucose and using it to make ATP from ADP?
Complete oxidation of glucose releases 686 kcal
Production of a standard amount of ATP from ADP absorbs 12 kcal
2 ATP are produced from every glucose molecule broken down by glycolysis
Efficiency of Energy required to make Glycolysis ATP
== Energy released by
oxidation of glucose

9. Efficiency of glycolysis = 3.5%
Much of the original energy contained in glucose is still held in pyruvic acid
NOT VERY EFFICIENT
Larger animals have greater energy requirements that cannot be satisfied by anaerobic pathways