1. PAUL VI CATHOLIC HIGH SCHOOL
CELL RESPIRATION
Chapter 9
CP Biology
PAUL VI CATHOLIC HIGH SCHOOL

2. CELL RESPIRATION Breathing and Respiration are not the same.
Breathing allows the exchange of O2 and CO2 between an organism and its environment.
In cellular respiration Mitochondria use O2 and produces CO2 as waste.
CO2 O2
Bloodstream
Muscle cells carrying out
Cellular Respiration
Breathing
Glucose + O2
CO2 +H2O +ATP
Lungs

3. CELL RESPIRATION
CO2
H2O
Glucose O2
ATP
ECOSYSTEM
Sunlight energy
Photosynthesis in chloroplasts
Cellular respiration in mitochondria
(for cellular work)
Heat energy +
Photosynthesis and cellular respiration provide energy for life
Cellular respiration makes ATP and consumes O2 during the oxidation of glucose to CO2 and H2O
Photosynthesis uses solar energy to produce glucose and O2 from CO2 and H2O

4. Multi-step process not a single reaction
Cellular respiration breaks down glucose molecules and banks their energy in ATP
-”Glucose” used in examples for convenience. Other organic molecules are also used as “food”
Glucose releases chemical bond energy, which the cell stores in the chemical bonds of ATP
Multi-step process not a single reaction
C6H12O6
CO2 6
H2O
ATPs
Glucose
Oxygen gas
Carbon dioxide
Water
Energy O2 +
Figure 6.3

5. CELL RESPIRATION
Electrons lose potential energy during their transfer from organic compounds to oxygen
When glucose is converted to carbon dioxide it loses hydrogen atoms, which are added to oxygen, producing water
C6H12O6
6 O2
6 CO2
6 H2O
Loss of hydrogen atoms (oxidation)
Gain of hydrogen atoms (reduction)
Energy
(ATP)
Glucose +

6. CELL RESPIRATION GLUCOSE CATABOLISM STAGE I: GLYCOLYSIS
STAGE II: PYRUVATE OXIDATION
STAGE III: KREBS CYCLE
STAGE IV: ELECTRON TRANSPORT

7. CELL RESPIRATION
Cellular Respiration Overview Video

8. Glycolysis harvests chemical energy by oxidizing glucose to pyruvate
Glycolysis harvests chemical energy by oxidizing glucose to pyruvate
ATP is used to prime a glucose molecule Which is split into two molecules of pyruvate
NAD+
NADH H+
Glucose
2 Pyruvate
ATP 2 P
2 ADP +
Figure 6.7A

9. CELL RESPIRATION

10. CELL RESPIRATION GLYCOLYSIS: 1. Glucose Priming:
occurs in the cytoplasm of every living cell
1. Glucose Priming:
changes glucose into a molecule that can be “cleaved”.
Requires 2 molecules of ATP
Phosphofructokinase: commits
glucose to glycolysis

11. PREPARATORY PHASE (energy investment)
In the first phase of glycolysis ATP is used to energize a glucose molecule, which is then split in two
 Steps      –   A fuel molecule is energized, using ATP. 1 3
Glucose
PREPARATORY PHASE (energy investment)
ATP
Step 1
ADP P
Glucose-6-phosphate 2 P
Fructose-6-phosphate
ATP 3
ADP P P
Fructose-1,6-diphosphate
 Step      A six-carbon intermediate splits into two three-carbon intermediates. 4 4
Figure 6.7C

12. CELL RESPIRATION 2. Splitting & Rearrangement: Six carbon compound
splits to (2) 3 “C” compounds.
Fructose 1,6, Diphosphate into (2) G3P (Glyceraldehyde-3-Phosphate)
“Substrate Level Phosphorylation”
Making ATP (4 molecules/glucose)

13. Organic molecule (substrate)
In Glycolysis ATP is produced by
substrate-level phosphorylation
- a phosphate group is transferred from an organic molecule to ADP using an enzyme
Enzyme
Adenosine
Organic molecule (substrate)
ADP
ATP P
Figure 6.7B

14. In the second phase of glycolysis ATP, NADH, and pyruvate are formed
Glyceraldehyde-3-phosphate (G3P)
 Step     A redox reaction generates NADH. 5 6 9
NAD  5
NAD 
ENERGY PAYOFF PHASE
NADH P 6
NADH P 6
+H
+H P P P P
1,3 -Diphosphoglycerate
 Steps     –      ATP and pyruvate are produced. 6 9
ADP
ADP 6 7 7
ATP
ATP P P
3 -Phosphoglycerate 7 P P 8 8
2-Phosphoglycerate 8
H2O
H2O P P
Phosphoenolpyruvate (PEP)
ADP 9
ADP 9 9
ATP
ATP
Pyruvate
Figure 6.7C

15. CELL RESPIRATION 3. Oxidation: Removal of electrons
(energy) & transfer to NAD+ NADH
4. ATP Generation: 4 reactions that
convert G3P to Pyruvate
- Generates 2 ATP per Pyruvate

16. CELL RESPIRATION
At the end of Stage 1 (Glycolysis) two molecules of pyruvate have been formed.
Pyruvate moves from the cytoplasm into the mitochondria.
NAD+
NADH H+
Glucose
2 Pyruvate
ATP 2 P
2 ADP +

17. CELL RESPIRATION Glycolysis Results in: Glucose 2 molecules Pyruvate
Each pyruvate 2 ADP ATP
Each G3P 2 NAD NADH

18. CELL RESPIRATION B. Oxidation of Pyruvate: Occurs in mitochondrion
1. Aerobic conditions Pyruvate
OXIDIZED to Acetyl CoA
2. Anaerobic conditions result
in FERMENTATION REACTIONS

19. CELL RESPIRATION

20. CELL RESPIRATION

21. CELL RESPIRATION FERMENTATION REACTIONS: 1.Lactic Acid Fermentation:
Pyruvate REDUCED to Lactate
No CO2 removal
NADH NAD+
2. Alcohol Fermentation:
Fungal (Yeast) Cells
Pyruvate REDUCED to Alcohol
CO2 Removed; NADH NAD+

22. CELL RESPIRATION

23. CELL RESPIRATION

24. CELL RESPIRATION C. KREBS CYCLE: 1. “Priming” Reactions
Prepares molecule for energy extraction
Acetyl CoA (2C) joins oxaloacetate (4C) to form Citrate (6C)
Citrate isomerizes to Isocitrate
Krebs Cycle/ Citric Acid Cycle Video

25. CELL RESPIRATION

26. CELL RESPIRATION C. KREBS CYCLE: 2. “Energy Extraction”
Oxidation rxns disassemble the molecule
Decarboxylation Reactions
Reduction NAD+ NADH
Reduction FAD+  FADH2
Regeneration oxaloacetate

27. CELL RESPIRATION

28. CELL RESPIRATION D. ELECTRON TRANSPORT System of REDOX reactions
Series of membrane electron carriers
Ubiquinone (quinone molecule)
Cytochromes (contain Fe++)
OXYGEN is final electron acceptor
Water is final product (two H+) attach to oxygen

29. CELL RESPIRATION

30. CELL RESPIRATION D. ELECTRON TRANSPORT: The movement of electrons down
the concentration gradient to
O2 (the final acceptor) sends
protons (H+) to the intermembrane
space ETC Video Video clip
Protons move thru ATP synthase
making ATP from ADP
(Oxidative Phosphorylation)
Gradients (ATP Synthase) video

31. Carriers bind and release electrons in redox reactions
Most ATP production occurs by Oxidative Phosphorylation
Most of the carrier molecules are included in the three main protein complexes
Carriers bind and release electrons in redox reactions
Intermembrane space
Inner mitochondrial membrane
Mitochondrial matrix
Protein complex
Electron flow
Electron carrier
NADH
NAD+
FADH2
FAD
H2O
ATP
ADP
ATP synthase H+ + P O2
Electron Transport Chain
Chemiosmosis .
OXIDATIVE PHOSPHORYLATION
+ 2 1 2
Figure 6.10

32. Resulting H+ gradient stores potential energy
Energy released redox reactions sed to pump H+ into the space between the mitochondrial membranes
Resulting H+ gradient stores potential energy
In chemiosmosis, the H+ diffuses back through the inner membrane through ATP synthase complexes
Driving the synthesis of ATP
Intermembrane space
Inner mitochondrial membrane
Mitochondrial matrix
Protein complex
Electron flow
Electron carrier
NADH
NAD+
FADH2
FAD
H2O
ATP
ADP
ATP synthase H+ + P O2
Electron Transport Chain
Chemiosmosis .
OXIDATIVE PHOSPHORYLATION
+ 2 1 2
Figure 6.10

33. CELL RESPIRATION ENERGY (ATP) YIELD per GLUCOSE
Glycolysis: 2 ATP (substrate level phosphorylation)
Ox. of Pyruvate: 2 NADH (3 ATP per)
Krebs Cycle: 6 NADH (3 ATP per)
2 FADH2 (1-2 ATP per)
2 ATP via GTP
Electron Transport: 32 ATP (oxidative phosphorylation)

34. CELL RESPIRATION

35. CELL RESPIRATION Alternate Sources for Metabolism
Glycolytic pathway thru ETS is
“final common pathway”
Other macromolecules can be utilized
Lipids via β-oxidation
Proteins via deamination (NH3)
Nucleic Acids via deamination

36. CELL RESPIRATION

37. CELL RESPIRATION Control of Glucose Catabolism Feedback inhibition
Phosphofructokinase inhibited by:
ATP levels
Citrate levels
Phosphofructokinase stimulated by
ADP levels
AMP levels

38. CELL RESPIRATION There is a mutualistic symbiotic
relationship between the products
of glycolysis and the reactants for photosynthesis.
This is an interrelationship between the mitochondria and chloroplast.

39. CELL RESPIRATION