Mitochondria and Electron Transport!
• Structure of the mitochondrion
• Transport systems of the mitochondrion
• The ETC
• Coenzymes of the electrons transport chain
Complete Oxidation of Glucose Mitochondria and Electron Transport!
Fate of Electrons Released upon Oxidation
! The “elementary” steps of the ﬁrst half-reaction takes place in the cytosol --
glycolysis and in the mitochondria -- citric acid cycle.
•TWELVE electron pairs -- 24 total
•These reduce 10 NAD+ and 2 FAD, yielding 10 NADH and 2 FADH . 2
! “Elementary” steps of the second half-reaction take place in the mitochondrion. The
12 electron pairs move from NADH and FADH to the electron transport chain. There are
more than 10 redox centers, in 4 enzyme complexes.
•Electron transfer pumps protons out of the matrix in the intermembrane space. The
resulting electrochemical gradient drives the synthesis of ATP from ADP and Pi in a
process known as oxidative phosphorylation.
The Mitochondrion: an ellipsoidal-shape organelle with the dimensions of 0.5-1
•A typical eukaryotic cell contains about 2000, only 20% of the cell volume.
•They contain their own DNA, ribosomes, and tRNA
•Thought to evolve from aerobic bacteria that formed symbiotic relationships with
•Outer membrane of the mitochondrion is permeable for molecules up to 10kD.
•The protein-rich inner membrane surrounds a matrix. the inner membrane is freely
permeable only to O ,CO2and H2O. 2
Concentrations of metabolites and ions in the intermembrane space are equal to those in
the cytosol. Metabolites are transported to and from the matrix via specialized systems.
Freeze-fracture and freeze-etch electron micrographs are used to visualize them.
•Density of inner