Cell Biology Lecture Notes p.653-672 Mitochondria and Chloroplast

Almost all eucaryotes have mitochondria. Membrane surface = critical. PMF to generate ATP, import metabolites, rotate flagella, etc. NADH 2e^-, 1H⁺ ferried to e^- carriers in ETS to O₂

Photosystems of chloroplast = reverse of mitochondrial. O₂ produced, CO₂ converted to CH₂O. Endosymbiosis: 1.5 X 10⁹ years ago. 18 X as much energy available of C oxidized to CO₂.

Mitochondria move about, change shape, fuse, etc. Guided by microtubules.High cooncentration in muscle, sperm tails (wrap around). 1/5th liver volume (1,000-2,000/cell)

Outer membrane = permeable to ,5,000 Dalton molecules. Inner membrane very tight, cardiolipin (4 fatty acids) [note: olestra =5 fatty acids; undigestible].

Matrix space has Krebs cycle enzymes, DNA genome, ribosomes, tRNA etc.

Inner membrane cristae(1/3rd of total)embedded with ETS carriers, ATPsynthase, transport proteins.

Acetyl CoA in matrix from (fat[1 month's energy]=6X as much energy as glycogen[1 day's energy] of equal mass). Overnight fast, mobilize fats (bad breath in morning). Excess sugar to glycogen, fat.

Adipocytes created early in life. Fatty acids oxidized 2C at a time to NADH, FADH₂, Acetyl CoA.

Glycogen's glucose cut in ½ to 2 pyruvate to 2 acetyl CoA eventually to 6 CO₂ (Pyruvate dehydrogenase of mitochondrial matrix)

Citric acid cycle: Enzymes in matrix. 7 enzyme-catalyzed reactions regenerate 4C molecule OAA

Carbon maximally oxidized to CO₂. FADH₂ bound. NADH+H⁺ floats free. Electrons to ETS.

1961 PMF=Peter Mitchell Force. Membrane potential + H⁺ gradient=PMF.. Cytosolic pH = intermembrane space pH.

Antiport coupling: ADP in ATP out. Normally have 10X [ATP] as [ADP]. This influences amount of energy obtainable from ATP hydrolysis!

11-13 kcal/mole at physiological concentrations. Delta G₀=7.3kcal/mole

Efficiency: biological systems 40% vs. human engines 10-20%.

Ultarsound-created submitochondrial particles: useful to construct artificial membrane-enclosed systems.

Reversible processes: H⁺ gradient and ATP synthesis.