Describe the structure of mitochondria and explain their role in respiration .

The mitochondria is a double membraned organelle, the inner of these membranes is invaginated to form structures called cristae. The fluid inside is called the mitochondrial matrix. The mitochondria has a pivotal role in the creation of ATP in aerobic cellular respiration. Glycolysis occurs outside the mitochondria, producing pyruvate and ATP, the pyruvate endures the link reaction on its way into the mitochondrial matrix and turns into acetyl co enzyme A. This acetyl group is used in the matrix in what is called Krebs cycle, where the oxidation of acetyl groups is coupled with the reduction of hydrogen carriers. The products of Krebs cycle are then transported to the electron transport chain on the cristae where the reduced NADH and FADH are then oxidized. The remaining hydrogen electrons are transported down the chain where an oxygen molecule is reduced to water. Chemiosmosis also occurs at the electron transport chain, in which hydrogen protons move down the concentration gradient (from the inner mitochondrion membrane) through an ATP synthase where ATP is generated. The multiple folds inside the mitochondria which are the cristae, mean that there is plenty of surface area for cellular respirations to occur at. 

In simple terms, the mitochondria is like the "powerhouse" of the cell. You can think of it as the principle in school! They serve as batteries, powering various functions of the cell and the organism as a whole. It's structure: it has a double membrane, the inner layer being folded inward to form layers. In the mitochondria the oxygen goes in the cells And takes part in the "kerbs cycle". In the cycle oxidation of food occurs and carbon dioxide is the biproduct.