Oxidative ATP Synthesis Electron transport chain – NADH – FADH2 – Ubiquinone – Cytochrome C Reactive oxygen
Peroxisome Single membrane Controlled H2O2 chemistry – Oxidases generate H2O2 – Peroxidases degrade H2O2 – Fatty acid metabolism – Cholesterol & bile synthesis Peroxins (PEX) control protein composition and biogenesis
Sarcoplasmic Reticulum Single membrane – Lamellar, fenestrated – Terminal cisternae Synthesis of transmembrane and extracellular proteins Calcium storage
SR T-tubule communication Terminal cisternae wrap T-tubule Communication of membrane events to SR Ogata & Yamasaki, 1997 SEM of I-band region of a myofiber with myofibrils extracted, leaving only membrane-bounded skeletons of T- tubule (T), SR (blue), terminal cisternae (arrowheads), and mitochondria. Fiber axis is vertical.
Triad Physical association between T-Tubule and SR “Feet” – Dihydropyridine receptor (DHPR) – Ryanodine Receptor (RyR) Franzini-Armstrong, 1970
“white” vs “red” muscle Red: larger, more extensive mitochondria White: (slightly) more extensive SR