1. Cellular Respiration

2. Cellular Respiration
A catabolic, exergonic, oxygen (O2) requiring process that uses energy extracted from macromolecules (glucose) to produce energy (ATP) and water (H2O).
C6H12O6 + 6O2  6CO2 + 6H2O + energy
glucose
ATP

3. Question:
In what kinds of organisms does cellular respiration take place?

4. Plants, Animals, Protists, Bacteria, and Fungi!!
Ex: Plants - Autotrophs: self-producers.
Ex: Animals - Heterotrophs: consumers.

5. Mitochondria Organelle where cellular respiration takes place. Inner
membrane space
Matrix
Cristae
Outer
membrane
Inner
membrane

6. Redox Reaction
Transfer of one or more electrons from one reactant to another.
Two types:
1. Oxidation
2. Reduction

7. Oxidation Reaction The loss of electrons from a substance.
Or the gain of oxygen.
C6H12O6 + 6O2  6CO2 + 6H2O + energy
Oxidation
glucose
ATP

8. Reduction Reaction The gain of electrons to a substance.
Or the loss of oxygen.
Reduction
glucose
ATP
C6H12O6 + 6O2  6CO2 + 6H2O + energy

10. Breakdown of Cellular Respiration
Four main parts (reactions).
1. Glycolysis (splitting of sugar)
a. cytosol, just outside of mitochondria.
2. Grooming Phase
a. migration from cytosol to matrix.

11. Breakdown of Cellular Respiration
3. Krebs Cycle (Citric Acid Cycle)
a. mitochondrial matrix
4. Electron Transport Chain (ETC) and
Oxidative Phosphorylation
a. Also called Chemiosmosis
b. inner mitochondrial membrane.

12. An Overview of Cellular Respiration

13. 1. Glycolysis Occurs in the cytosol just outside of mitochondria.
Two phases (10 steps):
A. Energy investment phase
a. Preparatory phase (first 5 steps).
B. Energy yielding phase
a. Energy payoff phase (second 5 steps).

14. 1. Glycolysis A. Energy Investment Phase: C-C-C-C-C-C C-C-C
Glucose (6C)
Glyceraldehyde phosphate (2 - 3C)
(G3P or GAP)
2 ATP used
0 ATP produced
0 NADH - produced
2ATP
2ADP + P

15. 1. Glycolysis B. Energy Yielding Phase
Glyceraldehyde phosphate (2 - 3C)
(G3P)
Pyruvate (2 - 3C)
(PYR)
0 ATP used
4 ATP produced
2 NADH - produced
4ATP
4ADP + P
C-C-C C-C-C
G3P
(PYR)

16. 1. Glycolysis Total Net Yield
2 - 3C-Pyruvate (PYR)
2 - ATP (Substrate-level Phosphorylation)
2 - NADH

17. The Energy Input and Output of Glycolysis

18. Substrate-Level Phosphorylation
ATP is formed when an enzyme transfers a phosphate group from a substrate to ADP.
Enzyme
Substrate O-
C=O
C-O-
CH2 P
Adenosine
ADP
(PEP)
Example:
PEP to PYR P
ATP O-
C=O
CH2
Product
(Pyruvate)
Adenosine

19. Fermentation Two Types:
Occurs in cytosol when “NO Oxygen” is present (called anaerobic).
Remember: glycolysis is part of fermentation.
Two Types:
1. Alcohol Fermentation
2. Lactic Acid Fermentation

20. Alcoholic Fermentation
Plants and Fungibeer and wine
glucose
Glycolysis C
C C
2 Pyruvic
acid
2ATP
2ADP
+ 2
2NADH P
2 NAD+ C
2 Ethanol
2CO2
released
2NADH
2 NAD+

21. Alcoholic Fermentation
2 Pyruvates + 2NADH + 2ATP 
2 Ethanols + 2 CO2 + 2 NAD+
Duff
Beer

22. Lactic Acid Fermentation
Animals (pain in muscle after a workout)
Glucose
Glycolysis C
2 Pyruvic
acid
2ATP
2ADP
+ 2
2NADH P
2 NAD+
C C
2 Lactic
acid
2NADH
2 NAD+ C

23. Lactic Acid Fermentation
End Products: Lactic acid fermentation
2 - ATP (substrate-level phosphorylation)
2 - Lactic Acids
2 – NAD+

24. 2. Grooming Phase Occurs when Oxygen is present (aerobic).
2 Pyruvate (3C) molecules are transported through the mitochondria membrane to the matrix and is converted to 2 Acetyl CoA (2C) molecules.
Cytosol C
2 Pyruvate
2 CO2
2 Acetyl CoA
C-C
2NADH
2 NAD+
Matrix

25. 2. Grooming Phase End Products: grooming phase 2 - NADH 2 - CO2
2- Acetyl CoA (2C)

26. 3. Krebs Cycle (Citric Acid Cycle)
Location: mitochondrial matrix.
Acetyl CoA (2C) bonds to Oxalacetic acid (4C - OAA) to make Citrate (6C).
It takes 2 turns of the Krebs Cycle to oxidize 1 glucose molecule.
Mitochondrial
Matrix

27. 3. Krebs Cycle (Citric Acid Cycle)
1 Acetyl CoA (2C)
3 NAD+
3 NADH
FAD
FADH2
ATP
ADP + P
(one turn)
OAA (4C)
Citrate (6C)
2 CO2

28. 3. Krebs Cycle (Citric Acid Cycle)
2 Acetyl CoA (2C)
6 NAD+
6 NADH
2 FAD
2 FADH2
2 ATP
2 ADP + P
(two turns)
OAA (4C)
Citrate (6C)
4 CO2

31. 3. Krebs Cycle (Citric Acid Cycle)
Total net yield (2 turns of Krebs Cycle)
ATP (substrate-level phosphorylation)
NADH
FADH2
CO2

32. Location: inner mitochondrial membrane.
4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis)
Location: inner mitochondrial membrane.
Uses ETC (cytochrome proteins) and ATP Synthase (enzyme) to make ATP.
ETC pumps H+ (protons) across innermembrane (lowers pH in innermembrane space).
Inner
Mitochondrial
Membrane

33. Each NADH converts to 3 ATP.
4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis)
The H+ then move via diffusion (Proton Motive Force) through ATP Synthase to make ATP.
All NADH and FADH2 converted to ATP during this stage of cellular respiration.
Each NADH converts to 3 ATP.
Each FADH2 converts to 2 ATP (enters the ETC at a lower level than NADH).

34. 4. Electron Transport Chain (ETC) and Oxidative Phosphorylation (Chemiosmosis)
Inner
membrane space
Matrix
Cristae
Outer
membrane
Inner
membrane

35. Chemiosmosis Couples the Electron Transport Chain to ATP Synthesis

36. Electron transport chain Oxidative phosphorylation
and chemiosmosis
Glycolysis
ATP
Inner
Mitochondrial
membrane H+
P i
Protein complex
of electron
carners
Cyt c I II
III IV
(Carrying electrons
from, food)
NADH+
FADH2
NAD+
FAD+
2 H+ + 1/2 O2
H2O
ADP +
Electron transport chain
Electron transport and pumping of protons (H+),
which create an H+ gradient across the membrane
Chemiosmosis
ATP synthesis powered by the flow
Of H+ back across the membrane
synthase Q
Oxidative phosphorylation
Intermembrane
space
mitochondrial
matrix
Figure 9.15
Chemiosmosis and the electron transport chain

37. 4. ETC and Oxidative Phosphorylation (Chemiosmosis for NADH)
ATP
Synthase
1H+
2H+
3H+
higher H+
concentration H+
ADP +
lower H+
(Proton Pumping) P E T C
NAD+
2H+ + 1/2O2
H2O
Intermembrane Space
Matrix
Inner
Mitochondrial
Membrane

38. 4. ETC and Oxidative Phosphorylation (Chemiosmosis for FADH2)
ATP
Synthase
1H+
2H+
higher H+
concentration H+
ADP +
lower H+
(Proton Pumping) P E T C
FAD+
2H+ +
1/2O2
H2O
Intermembrane Space
Matrix
Inner
Mitochondrial
Membrane

39. ATP TOTAL ATP YIELD 2. 34 ATP - ETC & oxidative phosphorylation
ATP - substrate-level phosphorylation
ATP - ETC & oxidative phosphorylation
18 ATP - converted from 6 NADH - Krebs Cycle
38 ATP - TOTAL YIELD
ATP

40. Eukaryotes (Have Membranes)
02 ATP - glycolysis (substrate-level phosphorylation)
04 ATP - converted from 2 NADH - glycolysis
06 ATP - converted from 2 NADH - grooming phase
02 ATP - Krebs cycle (substrate-level phosphorylation)
18 ATP - converted from 6 NADH - Krebs cycle
04 ATP - converted from 2 FADH2 – Krebs cycle
36 ATP - TOTAL

41. Maximum ATP Yield for Cellular Respiration (Eukaryotes)
Glucose
Glycolysis
2ATP ATP 6ATP 18ATP ATP ATP
2 ATP
(substrate-level
phosphorylation)
2NADH
6NADH
Krebs
Cycle
2FADH2
2 Pyruvate
2 Acetyl CoA
ETC and Oxidative
Phosphorylation
Cytosol
Mitochondria
36 ATP (maximum per glucose)

42. Prokaryotes (Lack Membranes)
Total ATP Yield
02 ATP - glycolysis (substrate-level phosphorylation)
06 ATP - converted from 2 NADH - glycolysis
06 ATP - converted from 2 NADH - grooming phase
ATP - Krebs cycle (substrate-level phosphorylation)
18 ATP - converted from 6 NADH - Krebs cycle
04 ATP - converted from 2 FADH2 - Krebs cycle
38 ATP - TOTAL

43. Question:
In addition to glucose, what other various food molecules are use in Cellular Respiration?

44. Catabolism of Various Food Molecules
Other organic molecules used for fuel.
1. Carbohydrates: polysaccharides
2. Fats: glycerol and fatty acids
3. Proteins: amino acids