1. Cell Energy

2. Chemical Energy in Food
Much of the E in a hamburger is
stored in the form of proteins, fats
and carbohydrates.
Before you can use this E, it is transferred to the bonds between the phosphates in ATP through a process called cellular respiration
Oxygen in the air you breath makes the production of ATP more efficient but ATP can be made without oxygen
- Aerobic – metabolic processes requiring oxygen
- Anaerobic – metabolic processes that do not require oxygen

3. Chemical Energy in Food
The cell would be destroyed if it burned food and released the entire E at once, so instead it must release a little at a time through a process known as cellular respiration.
3 steps of cellular respiration if oxygen is present:
Glycolysis
Kreb’s Cycle
Electron Transport Chain (ETC)

4. Overview of Cellular Respiration
Cellular Respiration: process that releases E by breaking down glucose (and AA & FA) molecules.
This is the overall equation but it happens in many steps.
6O2 + C6H12O6  6CO2 + 6H2O + Energy
oxygen + glucose  carbon dioxide + water + energy

5. Where Does Cellular Respiration Take Place?
It actually takes place in two parts of the cell:
Glycolysis occurs in the cytoplasm
Krebs Cycle & ETC take place in the mitochondria

6. Mitochondria Structure
Smooth outer membrane
Folded inner membrane - these
folds are called the cristae
Space inside cristae is called the matrix

7. Stages of Cellular Respiration

8. Diagram of the Process Occurs across Cristae Occurs in Cytoplasm
Occurs in Matrix

9. Glycolysis ATP Production: net gain of 2
NADH Production: NAD+ (electron acceptor) accepts a pair of electrons to form the electron carrier NADH, which will then carry these electrons until they are needed later in the ETC to make more ATP.
Glucose - hexose 1. 2.
Pyruvic acid 3.

10. Fermentation – No Oxygen
The recycling of NAD+ is called fermentation
Occurs in the cytoplasm
2 types of fermentation
Alcoholic
Lactic Acid

11. Lactic Acid Fermentation (Anaerobic)
Many cells will do lactic acid fermentation when they run out of O2.
Makes NO additional ATP, (only the 2 from glycolysis)
Pyruvate + NADH  lactic acid + NAD+

12. Alcoholic Fermentation
Just as in lactic acid fermentation, NAD+ is recycled and glycolysis can continue to produce ATP
Produces ethanol & CO2
Carried out by yeast and some
bacteria
Used in making foods and
drinks – bread, beer, wine
Pyruvate + NADH  alcohol + CO2 + NAD+

13. Alcoholic Fermentation
Carbon dioxide released by yeast causes bread to rise and the carbonation of beer
Rubbing alcohol and nail polish remover are also produced by alcoholic fermentation

14. Overview of Cellular Resp.