Principles of Biochemistry (2+1)

The mitochondrion is called the power house of the cell, since it is within this organelle that most of the capture of energy derived from oxidation of food. The system in mitochondria that couples oxidation to the generation of the high energy intermediate, ATP, is termed oxidative phosphorylation. Mitochondria have an outer membrane that is permeable to most metabolites, an inner membrane which is selectively permeable and which forms folds or cristae, and a matrix with the inner membrane. They are consumed together in hundreds of grams per day, depending upon body weight, age and sex.The soluble enzymes of the citric acid cycle and the enzymes of beta oxidation of fatty acids are found in the matrix, necessitating mechanisms for transporting metabolites and nucleotides across the inner membrane. All the useful energy liberated during the oxidation of carbohydrates, fatty acids and amino acids are made available within mitochondria as reducing equivalents –H or electrons.

The mitochondria contain a series of catalysts called respiratory chain or electron transport particles . That collect and transport reducing equivalents and direct them to their final reaction with hydrogen to form water and the machinery for trapping the liberated free energy as high energy.