1. Cellular Respiration

2. Cellular Respiration
Energy in food is stored as carbohydrates, proteins & fats. Before you can use that energy, it must be released and transferred to ATP.

3. Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen.
Formula:
C6H12O6 + 6O CO2 + 6H2O + 34 ATP
Glucose+ Oxygen CO2 + H2O + Energy

4. 3 Steps of Cellular Respiration
If cellular respiration took place in just one step, all energy would be released at once and our cells need to control this.

5. Glycolysis – The process in which one molecule of glucose is broken in half, producing 2 molecules of pyruvic acid (a 3 carbon compound)
Glucose C6
Pyruvate Pyruvate
C C3
2 ADP + 2NAP+
2 ATP + 2NADH

6. Glycolysis… Takes place in the cytoplasm Net gain of 2 ATP
Takes place without oxygen (anaerobic)
NADH is formed (electron carrier)
Interesting Fact:
Since bacteria don’t have any membrane-bound organelles such as mitochondrion, they can only produce ATP by glycolysis!

7. Two Things Can Happen: (in Eukaryotic Cells)
1. Anaerobic Respiration - If no oxygen is present, pyruvate goes through a process called “fermentation.”
2. Aerobic Respiration – If oxygen is present, pyruvate enters the mitochondria and enters the “Kreb’s Cycle.”

8. Two Pathways Anaerobic Or: Aerobic What’s the difference? C6
Glycolysis C3

9. Fermentation – Recycles the NAD+ that is needed to make ATP in the absence of oxygen.
Pyruvate
Alcohol Lactic Acid
(plants) (animals)
2 ATP
CO2
~ Takes place in the cytoplasm

10. Lactic acid is produced in your muscles during rapid exercise when the body cannot supply enough oxygen to the tissues.
The buildup of lactic acid causes a painfull burning sensation.

11. 2. Krebs Cycle – A stage of aerobic (requires oxygen) respiration in which pyruvate is converted into CO2, water and ATP.
~ Takes place in the mitochondria

12. What happens to all of the high energy electrons???
The Kreb’s Cycle is a continuous cycle of electrons transferred to energy carriers.
Citric acid is broken down, CO2 is released (you exhale it out), and ATP is released to be used in cellular activities.
What happens to all of the high energy electrons???
Citric Acid

13. 3. Electron Transport Chain – Takes place along the inner membrane of the mitochondria.
A protein in the membrane called ATP synthase. These enzymes convert ADP to ATP.
34 ATP are produced (Lots of energy!)

14. Electron Transport Chain

15. ATP Synthase

16. The Totals
In the absence of oxygen, glycolysis produces just 2 ATP molecules per glucose.

17. In the presence of oxygen, everything changes.
The Kreb’s Cycle & electron transport chain allow the cell to produce 34 more ATP molecules.
36 total ATP!

18. 18 times as much can be generated from glucose in the presence of oxygen.
The final waste products are water and carbon dioxide.

19. So….Why do we breathe?

20. 38% of the energy in glucose is used to make ATP
38% of the energy in glucose is used to make ATP. 62% is released as heat. (This is why you become warm when you exercise).

22. Comparing Photosynthesis & Cellular Respiration
Function
Location
Reactants
Products
Equation

23. Photosynthesis & Cellular Respiration are almost opposite processes.
Photosynthesis “stores” energy
Cellular Respiration “releases” energy
What do you notice about the equations????