1. Cell Respiration and Fermentation

2. Cell Respiration
Cell Respiration is the process of breaking down organic compounds (glucose) to produce ATP
Requires the use of mitochondria
Both autotrophs and heterotrophs use cell respiration
Cell respiration is divided into 2 stages:
Glycolysis
Aerobic Respiration

3. Circle of Life Cell Respiration mirrors photosynthesis:
Light + 6H2O + 6CO2  C6H12O6 + 6O2
Cell Respiration:
C6H12O6 + 6O2  6H2O + 6CO2 + ATP

4. Cell Respiration Cell Respiration is divided into 2 stages:
1st Step: Glycolysis
2nd Step: Aerobic Respiration

5. 1st Step: Glycolysis
Glycolysis occurs in the cytoplasm where glucose is broken down.
2 pyruvic acid molecules & net of 2 ATP molecules are formed
Pyruvic acid must be broken down further through the process of aerobic respiration or anaerobic respiration (depending on the availability of O2)

6. 2nd Step: Aerobic Respiration Pathway
Aerobic Respiration takes place in the mitochondria in all eukaryotes only if oxygen is present in the cell.
There are 2 steps to Aerobic Respiration:
Krebs Cycle
Electron Transport Chain (ETC)

7. Krebs Cycle: 1st Part of Aerobic Respiration
The Krebs cycle takes place in the mitochondrial matrix
Breaks down Pyruvic acid from glycolysis to produce CO2 and net 2 ATP
Produces NADH and FADH2 molecules (energy molecules) to power the Electron Transport Chain (ETC)

8. ETC: 2nd Part of Aerobic Respiration
The Electron transport chain (ETC) takes place on the inner membrane of the mitochondria.
Electrons from NADH and FADH2 are passed molecule-to-molecule in the ETC allowing for ATP Synthase to produce ATP
End Products for ETC are H2O and 34 ATP molecules

10. Fermentation Pathway
Anaerobic Respiration is also known as Fermentation
Fermentation is an additional biochemical pathway if oxygen is not present in the cell
Anaerobic Respiration occurs only in the cytoplasm
There are 2 steps to fermentation:
Glycolysis – breaking down glucose into pyruvic acid
Anaerobic Respiration (Fermentation) – breaking down pyruvic acid in one of the 2 pathways: alcoholic fermentation or lactic acid fermentation

11. Lactic Acid Fermentation
Lactic acid fermentation is the biochemical pathway converting pyruvic acid into lactic acid without producing additional ATP
Lactic acid fermentation occurs with muscle fatigue
Can be used to make dairy products

12. Alcoholic Fermentation
Alcoholic fermentation is the biochemical pathway converting pyruvic acid into ethyl alcohol and CO2 producing no additional ATP
Can be used to make alcohol such as beer, wine, and bread.

13. Energy Produced by Cellular Respiration
Cell Respiration can produce up to 38 ATP molecules from a single molecule of glucose
Glycolysis produced 2 ATP molecules
Aerobic respiration produced 36 ATP molecules
Anaerobic Respiration produced – ATP
Thus, cell respiration produced is nearly 20 times more efficient than glycolysis alone.