1. Anatomy and Physiology
Cellular Respiration
Anatomy and Physiology

2. What is Cellular Respiration?
The process of converting food energy into ATP energy
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + 36 ATP
(glucose) (oxygen) (carbon dioxide) (water) (ATP)

3. Why are both Photosynthesis and Cell Respiration important to Ecosystems?
Light is the ultimate source of energy for all ecosystems
Chemicals cycle and Energy flows
Photosynthesis and cellular respiration are opposite reactions

4. Why do plants need both chloroplasts and mitochondria?
Chloroplasts use energy from the sun to make glucose
Mitochondria convert glucose to ATP—the energy currency of the cell

5. What is ATP? Adenosine Triphosphate
5-Carbon sugar (Ribose)
Nitrogenous base (Adenine)
3 Phosphate groups
The chemical bonds that link the phosphate groups together are high energy bonds
When a phosphate group is removed to form ADP and P, small packets of energy are released

6. How is ATP used?
As ATP is broken down, it gives off usable energy to power chemical work and gives off some nonusable energy as heat.
Synthesizing molecules for growth and reproduction
Transport work – active transport, endocytosis, and exocytosis
Mechanical work – muscle contraction, cilia and flagella movement, organelle movement

7. Why use ATP energy and not energy from glucose?
Breaking down glucose yields too much energy for cellular reactions and most of the energy would be wasted as heat.
1 Glucose = 686 kcal
1 ATP = 7.3 kcal
1 Glucose → 36 ATP
How efficient are cells at converting glucose into ATP?
38% of the energy from glucose yields ATP, therefore 62% wasted as heat.

8. Cellular Respiration is a Redox Reaction
(Oxidation)
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
Oxidation is the loss of electrons or H+
Reduction is the gain of electrons or H+
Glucose is oxidized when electrons and H+ are passed to coenzymes NAD+ and FAD before reducing or passing them to oxygen.
Glucose is oxidized by a series of smaller steps so that smaller packets of energy are released to make ATP, rather than one large explosion of energy.
(Reduction)

9. Cell Respiration can be divided into 4 Parts:
1) Glycolysis
2) The Citric Acid (Krebs) Cycle
4) The Electron Transport Chain and
Chemiosmotic Phosphorylation

10. Where do the 4 parts of Cellular Respiration take place?
Glycolysis:
Cytosol
The Krebs Cycled:
Matrix
Electron Transport Chain
Cristae

11. Parts of the Mitochondria

12. Anaerobic Respiration (no oxygen required, cytoplasm)
Glycolysis
Glucose  2 Pyruvate
2 ATP
Aerobic Respiration (oxygen required, mitochondria)
2. Oxidation of
Pyruvate
2 Pyruvate  2 CO2
2 Acetyl CoA
Krebs Cycle
2 Acetyl CoA  4 CO2
2 ATP
Electron
Transport
Chain
(chemiosmotic)
6 O2  32 ATP
6 H2O
Total: 36 ATP produced

13. ATP is made in two ways:
1) Substrate Level Phosphorylation (glycolysis & Krebs cycle)
2) Chemiosmotic Phosphorylation (electron transport chain)
Substrate-Level Phosphorylation:
Energy and phosphate are transferred to ADP using an enzyme, to form ATP. Phosphate comes from one of the intermediate molecules produced from the breakdown of glucose.

14. Review ATP Production:
1) Glycolysis → 2 ATP
2) Oxidation of Pyruvate → No ATP
3) The Krebs Cycle → 2 ATP
4) The Electron Transport Chain and Chemiosmotic Phosphorylation:
Each NADH produces 2-3 ATP so NADH → 28 ATP
Each FADH2 produces 2 ATP so FADH2 → 4 ATP
Total = 36 ATP
1 Glucose = 686 kcal
1 ATP = 7.3 kcal
1 Glucose → 36 ATP
How efficient are cells at converting glucose into ATP?
38% of the energy from glucose yields ATP, therefore 62% wasted as heat (used to maintain body temperature or is dissipated)
Ex. Most efficient Cars: only 25% of the energy from gasoline is used to move the car, 75% heat.

15. All Types of Molecules can be used to form ATP by Cell Respiration:
Proteins, Carbohydrates, and Lipids must first be broken down into their monomers and absorbed in the small intestine.
Monomers may be further broken down into intermediate molecules before entering different parts of Cell respiration to ultimately form ATP.

16. Anaerobic Respiration: Fermentation
If there is NO oxygen, then cells can make ATP by Fermentation
Without oxygen, Oxidation of Pyruvate and the Electron Transport Chain do not operate.
Glucose → Pyruvate → Lactate
NAD+ Glycolysis 2 NADH Reduction Rxn or
2 ATP Alcohol + CO2
Fermentation yields a net gain of 2 ATP by substrate level phosphorylation for every 1 Glucose. (Inefficient)
Two Forms of Fermentation:
Lactic Acid Fermentation (animals)
Alcohol Fermentation (yeast)