2. Overview of Cellular Respiration
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Overview of Cellular Respiration
Organisms obtain energy in a process called cellular respiration.
Formula:

3. Cellular respiration occurs in two main parts.
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Cellular respiration occurs in two main parts.
Glycolysis (Anaerobic)
Aerobic respiration (Kreb’s Cycle)

5. Glycolysis: Glucose is broken down in the cytoplasm of the cell.
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Glycolysis
Glycolysis: Glucose is broken down in the cytoplasm of the cell.
The process does NOT require oxygen: anaerobic

6. Glycolysis Occurs in the Cytoplasm—Not in an Organelle!!

7. Glycolysis
Enzymes break down one molecule of glucose (C6H12O6) into 2 pyruvic acid (C3H4O3) molecules and 4 hydrogens
The process needs 2 ATP molecules to get started—it creates 4 ATP
Net gain of ATP in glycolysis is 2 ATP

8. Overhead Diagram

9. Aerobic Respiration Stage (Kreb’s Cycle)
Chapter 8
Cellular Energy
8.3 Cellular Respiration
Aerobic Respiration Stage (Kreb’s Cycle)
Glycolysis has a net result of two ATP and two pyruvic acid molecules.
Most of the energy from the glucose is still contained in the pyruvic molecules.
The pyruvic acid needs to be broken down.

10. The two pyruvic acid molecules move into the mitochondria by active transport (this requires 2 ATP)
Aerobic respiration takes place in the mitochondria (must have oxygen)

11. The pyruvic acid is acted upon by enzymes and broken down into acetic acid —2 ATPs are formed
Acetic acid is acted upon by enzymes and broken down into citric acid
CO2 and H2O are given off as waste

12. 36 ATP are formed, but 2 are used to get the pyruvate into the mitochondria
2 ATP from glycolysis + 34 ATP from aerobic respiration = 36 ATP (net result)