BIO 330 Cell Biology
Lecture Outline
Spring 2011
Chapter 10: Aerobic Respiration
I. Cellular Respiration: Overview
A. Aerobic vs anaerobic respiration
B. Aerobic respiration vs fermentation
C. Overall process
Glycolysis
Pyruvate oxidation to Acetyl CoA
TCA cycle
Electron transport
ATP synthesis
II. The Mitochondrion
A. Mitochondrial location
B. Structure
Two membranes (outer vs inner)
Three regions
Intermembrane space
Matrix
Intracristal spaces
C. Functional / structural relationship
D. Bacteria lack mitochondria
Similar processes occur at the plasma membrane
III. The Tricarboxylic Acid Cycle
A. Oxidation of pyruvate to Acetyl CoA
Oxidative decarboxylation
Pyruvate dehydrogenases (PDH)
Produces 1 CO2 and 1 NADH per pyruvate
B. Acetyl CoA enters the TCA cycle
Citrate synthase forms citrate
Aconitase converts citrate to isocitrate
C. Oxidative decarboxylations
Isocitrate dehydrogenase removes CO2 and forms oxalosuccinate, then -ketoglutarate
-ketoglutarate dehydrogenase removes CO2 and forms succinyl CoA
D. ATP production
Co A is released; energy is used to generate ATP or GTP
E. NADH and FADH2 generation & oxaloacetate regeneration
Succinate dehydrogenase forms fumarate and FADH2
Fumarate hydrates forms malate
Malate dehydrogenase forms oxaloacetate and NADH
F. Summary of TCA cycle
BIO 330 Cell Biology
Lecture Outline
Spring 2011
Acetyl CoA + 3NAD+ + FAD + ADP + Pi  2CO2 + 3NADH + FADH2 + CoA—SH + ATP
For each glucose molecule: 6 NADH, 2 FADH2, and 2 ATP are produced
For each glucose molecule, including glycolysis, Acetyl CoA formation, and TCA cycle:
10 NADH, 2 FADH2, 4 ATP
G. Regulation of TCA cycle
Allosteric regulation of TCA cycle enzymes
NADH, ATP, Acetyl CoA are allosteric regulators
PDH regulation by phosphorylation
H. Lipid and protein catabolism; and protein and nucleic acid anabolism via TCA cycle
Amphibolic cycle
IV. Electron Transport
A. Electron transport system overview
Electrons are transferred from NADH and FADH2 to O2
Creates water
Releases free energy
Electron transfer occurs in stepwise fashion to maximize efficiency
B. Five kinds of electron carriers are parts of respiratory complexes
Flavoproteins
Carry electrons and protons together
Iron-sulfur proteins
Carry only one electron by redox of iron ions
Cytochromes
Contain heme; carry only one electron
Copper-containing cytochromes
Fe-Cu center holds O2 until 4 electrons are received
Coenzyme Q (a quinone; aka ubiquinone)
Accepts both electrons and protons; transfers protons across membrane
C. Sequence of electron transport
The position of each carrier is determined by its standard reduction potential
Electrons enter either via Complex I or Complex II
NADH donates to Complex I
FADH2 donates to Complex II
Complexes I and II both pass electrons to CoQ, which then passes them to Complex III
Complex III passes electrons to Cyt c, which then passes them to Complex IV
Complex IV passes electrons to O2 as the terminal electron acceptor
V. The Electrochemical Proton Gradient
A. Chemiosmotic Model
Proton gradient across the inner mitochondrial membrane links electron transport with
ATP production
BIO 330 Cell Biology
Lecture Outline
Spring 2011
B. Energy yields
Each NADH provides enough energy to produce 3 ATP
Each FADH2 provides enough energy to produce 2 ATP
C. Proton motive force
VI. ATP Synthesis
A. F0F1 complex
F0 is a membrane-bound proton channel subunit (proton translocator)
F1 is an ATPase / ATP synthase subunit attached to F0
B. F0 structure
a, b, c subunits
a is the proton channel
b connects F0 to F1
multiple c subunits form a rotating ring that turns the  subunit of F1
C. F1 structure
 helps 
 is catalytic site for ATP synthesis
 is rotating stalk that turns inside of the  3 3 wheel
immobilizes  3 3 wheel
anchors  subunit to c ring of F0
D. Binding change model of ATP synthesis
subunit has 3 different conformations, each with different affinities for ADP and ATP
L (loose) – binds ADP and and Pi loosely
T (tight) – binds ADP and Pi tightly and catalyzes condensation
O (open) – low affinity for both ADP and ATP