This document outlines cellular respiration and its key stages and processes. It begins by stating the objectives of describing the major features of respiration, differentiating aerobic from anaerobic respiration, distinguishing the major stages, and explaining the pros and cons of fermentation and aerobic respiration. It then defines cellular respiration and describes the three main stages: glycolysis, the Krebs cycle, and the electron transport chain. It provides details on each stage, including where they take place in the cell, their inputs and outputs, and how ATP is generated through chemiosmosis. In summary, cellular respiration completely breaks down glucose to produce 36-38 molecules of ATP.

2. Objectives:
At the end of our lesson, you should be able to:
1. Describe the major features and chemical events in
respiration;
2. Differentiate aerobic from anaerobic respiration;
3. Distinguish major features of glycolysis, Krebs Cycle,
ETS, and chemiosmosis;
4. Explain the pros and cons of fermentation and aerobic
respiration.

3. Cellular Respiration
• C6H12O6 + 602  6CO2 + 6H20
• A catabolic pathway
• Oxygen is consumed as a reactant along with organic compounds.
• Involves three stages:
• Glycolysis
• Krebs Cycle
• Electron Transport Chain

5. What Is ATP?
• Adenosine Triphosphate
• Energy used by all Cells
• Organic molecule containing high-energy Phosphate bonds

6. Chemical Structure of ATP

7. What Does ATP Do for You?
 It supplies YOU with ENERGY!

8. How Do We Get Energy From
ATP?
 By breaking the
high- energy
bonds between
the last two
phosphates in
ATP

9. NADH and FADH2
 NAD+ traps electrons
from glucose to make
NADH (energy stored)
 Similarly, FAD+ stores
energy as FADH2

10. 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

11. Review of Mitochondria
Structure
 Smooth outer
Membrane
 Folded inner
membrane
 Folds called
Cristae
 Space inside
cristae called the
Matrix

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

13. Glycolysis
1. Means “splitting of sugar”
2. Occurs in the cytosol of the cell
3. Partially oxidizes glucose (6C) into two pyruvate
(3C) molecules.
4. Occurs whether or not oxygen is present.

14. 5. An exergonic process, (meaning energy is released)
most of the energy harnessed is conserved in the high-
energy electrons of NADH and in the phosphate bonds of
ATP

16. Glycolysis Summary
• Takes place in the Cytoplasm
• Anaerobic (Doesn’t Use Oxygen)
• Requires input of 2 ATP
• Glucose split into two molecules of Pyruvate
• Also produces 2 NADH and 4 ATP

17. Formation of Acetyl CoA
1. Junction between glycolysis and Krebs cycle
2. Oxidation of pyruvate to acetyl CoA
3. Pyruvate molecules are translocated from the cytosol into
the mitochondrion by a carrier protein in the mitochondrial
membrane.
4. A CO2 is removed from pyruvate – making a 2C compound.
5. Coenzyme A is attached to the acetyl group.

18. Formation of Acetyl CoA

19. Formation of Acetyl CoA

20. Krebs Cycle
 Requires Oxygen (Aerobic)
 Cyclical series of oxidation reactions that
give off CO2 and produce one ATP per cycle
 Turns twice per glucose molecule
 Produces two ATP
 Takes place in matrix of mitochondria

23. Krebs Cycle Summary
 Each turn of the Krebs Cycle also produces
3NADH, 1FADH2, and 2CO2
 Therefore, For each Glucose molecule, the
Krebs Cycle produces 6NADH, 2FADH2,
4CO2, and 2ATP

25. Electron Transport Chain
1. Located in the inner membrane of the
mitochondria.
2. Oxygen pulls the electrons from NADH and
FADH2 down the electron transport chain to a
lower energy state
.
3. Process produces 34 ATP or 90% of the ATP in
the body.

26. Electron Transport Chain
4. Requires oxygen, the final electron acceptor.
5. For every FADH2 molecule – 2 ATP’s are produced.
6. For every NADH molecule – 3 ATP’s are produced.
7. Chemiosmosis – the production of ATP using the
energy of H+ gradients across membranes to
phosphorylate ADP.

27. ATP Synthase
 A protein in the inner membrane in the mitochondria.
 Uses energy of the ion gradient to power ATP synthesis.
 For every H+ ion that flows through ATP synthase, one ATP
can be formed from ADP

30. Cellular Respiration in Summary
Glycolysis
• 2 ATP
• 2 NADH  4-6 ATP (Depends on how this NADH
molecule gets to the ETC. To make things simple we
will say that these two NADH’s make 4 ATP )
Formation of Acetyl CoA
• 2 NADH  6 ATP

31. Cellular Respiration in Summary
Krebs Cycle
• 2 ATP
• 6 NADH  18 ATP
• 2 FADH2  4 ATP
Grand Total = 36 ATP

32. Fermentation
 Occurs when O2 NOT present (anaerobic)
 Called Lactic Acid fermentation in muscle
cells (makes muscles tired)
 Called Alcoholic fermentation in yeast
(produces ethanol)
 Nets only 2 ATP