1. Citric Acid Cycle Overview
Stage 3 Digestion
Citric Acid Cycle Overview

2. Warm-up Draw the entry level Rx of Glycolysis.
What’s the enzyme named catalyzing it?
Name the inhibitor of that enzyme.
How many ATP are made?

3. Pyruvate

4. The 3 Uses of Pyruvate it is turned into
Product
Acetyl CoA
Ethanol
Lactic Acid
condition
Aerobic
Anaerobic
organism
Any eukaryotic cell
Yeast
Muscle cells
organell
Mitochondria
Cytosol
purpose
Endoxidation
Making more NADH, ATP
Regeneration of NAD for continued glycolysis

5. Two types of Fermentation: A. Lactic Acid - Muscles
Produces no CO2
Lactic Acid is degraded in liver ≈3-5 hrs
Does not produce post-workout muscle pain!!!

6. B. Alcoholic Fermentation in Yeast
* Produces Ethanol and CO2

7. Endoxidation
Needs O2 (aerobic) and Mitochondria to completely harvest the chemical energy left in pyruvate
Pyruvate is converted to Acetyl CoA, loss of 1st Carbon as CO2
Enters
Mitochondria

8. Mitochondria Eukaryotic cell organelle
Has two membranes (like nucleus)
Outer membrane believed to originate from endosymbiontic theory: mitochondria were once independent organisms:
Has it’s own DNA and ribosomes
Inherited from the mother

9. Structure of Mitochondria

10. Endosymbiotic Theory
Endosymbiosis
animation

11. Citric Acid Cycle (Krebs C)
Central pathway for metabolizing carbs, lipids and proteins
Location: Mitochondrial Matrix
Has two parts: Decarboxylation and Regeneration
Components are natural acids: Citric-, Malic, Oxalic-, Fumaric acid
Acids in fruits/vegetables are metabolized in the citric acid cycle

12. Warm-up
1. Where: Glycolysis or Krebs Cycle would you find this molecule?
2. What’s its name?
3. What do all molecules in the Krebs Cycle have in common?

13. Stage 4 Digestion: Electron Transport Chain and ATP Synthesis

14. Electron Transport Chain- ETC
Interconnected proteins (Cytochromes, Ferroproteins, CoQ…. ) labeled
Complex I-V
embedded in the
inner
mitochondrial
membrane

15. A. Unloading of NADH/FADH
NADH and FADH (Complex II) molecules go to Complex I – Dehydrogenase and unload the H
Unloaded NAD/FAD go back to Krebs Cycle/Glycolysis
H is separated into high energy e- and H+

16. B. Proton Pumps
High energy e- passes through complexes I,II, III, IV – proton pumps that use e- energy to pump H+ into mitochondrial intermembrane space
This creates a 100 x H+ difference between matrix and intermembrane space:
H+ gradient: Chemiosmosis

17. C. The Role of Oxygen Complex IV: energy of e- has been used up
Oxygen (very e-negative) absorbs e- on the matrix side – where it is neutralized by H+ gradient forming water
½ O2 + 2e- + 2H H2O
Oxygen is the final electron acceptor of aerobic cellular respiration – this is why you breathe!!!

18. D. ATP Synthesis Harvesting energy of the H+ gradient
Works like a water wheel

19. ATP Synthase: Complex V
allows H+ gradient to rush through using energy to make ATP
ADP + P+ ENERGY ATP

20. ADP + P ATP

21. animated ATP synthase
Electron Transport Chain
Cellular respiration all
Glycolyis
Krebs cycle

23. ATP Conversions 1 cytosolic NADH = 2 ATP 1 mitochondrial NADH = 3 ATP
1 mitochondrial FADH = 2 ATP

24. Net ATP from 1 Glucose 2 ATP (G) 2 2 NADH2 (G) = 2 FADH2 (transport) 4
2NADH2 (K prep) 4
2 x 3 NADH2 (K)
2 x FADH2 (K) 4
2 x 1 GTP (K) 2__
Total ATP

25. Location?Location?Location?
In which cellular compartment houses the…
Glycolysis
Citric Acid Cycle
Electron Transport Chain
Hydrogen Ion gradient
ATPsynthase

26. Warm-up
1. Write the balanced net reaction of anaerobic cellular respiration of 1 mole of Glucose to Lactic Acid. 2. Write the balanced net reaction of aerobic cellular respiration of 1 mole of Glucose. 3. Give two reasons why cells convert Pyruvate to Lactic acid during temporary anaerobia.

27. Warm-up The enthalpy for I mole of ATP is -30 kJ.
The enthalpy of combustion for 1 mole of glucose is kJ.
1. Calculate the efficiency of aerobic cellular respiration by multiplying # ATP with the enthalpy then comparing it to the combustion enthalpy. How much chemical energy is captured and how much energy is lost?
2. According to the law of conservation of energy, energy cannot be created or destroyed, only transferred. What happened to the the energy difference?

28. Lipid Metabolism Cytoplasm: lipase separates Glycerol and Fatty Acids
Glycerol (C3) is converted to Pyruvate (C3): yields NADH
Fatty Acids are transported into Mitochondria for β-Oxidation
chopped into 2 carbon molecules to make Acetyl-CoA (Krebs Cycle)
Yield: 1 NADH + 1 FADH/chop
ondrial matrix

29. Amino Acids Liver: Removal of amino group as NH3 (ammonia)
Ammonia is toxic, reacts with CO2 to form urea, secreted as liquid waste: kidneys O
2NH3 + CO NH2-C-NH2 + H2O
Ammonia Urea

30. Carbon skeleton of AA AA skeletons with 2 C → Acetyl
AA skeletons with 3 C →Pyruvate
AA skeletons with 4 C → Succinate Fumarate, Malate, Oxaloacetate
AA skeletons with 5 C→ α-Ketoglutarate