AEROBIC RESPIRATION

=Aerobic Respiration= '''Glucose + Oxygen → Carbon Dioxide + Water + ATP (Cellular Energy)''' [image:http://i.imgur.com/vXlVeHK.png?2] Aerobic respiration is a form of cellular respiration that uses oxygen. Aerobic respiration yields much more energy than anaerobic respiration. This is actually why we breathe; oxygen is needed by our cell so that they can carry out aerobic respiration. Without oxygen our cells would not be able to convert our food (chemical potential energy) into enough usable energy and all our cellular processes would come to a halt. Aerobic respiration occurs in the mitochondria. Cells with high energy demands such as muscle cells will have larger numbers of mitochondria so that they can produce more energy (ATP) by aerobic respiration. Aerobic respiration actually involves a series of chemical reaction. They key stages have been outlined below. ==Glycolysis== '''Glucose → Pyruvate + ATP''' Glucose is split in half forming two '''pyruvate''' molecules. This process does not require oxygen. If no oxygen is present the pyruvate can be broken down into Lactic Acid or Alcohol yielding a little extra energy (2 ATP). This is known as '''anaerobic respiration''' or '''fermentation'''. Gylcolysis occurs in the cell '''cytoplasm''' ==Krebs Cycle== '''Pyruvate → Carbon Dioxide + Hydrogen + ATP''' [image:http://i.imgur.com/Zb4keTy.png?1] The pyruvate molecules then combine with an enzyme cofactor called '''Coenzyme-A''' producing '''Acteyl-CoA'''. Acetyl-CoA then enters the Krebs Cycle (also known as the TCA or Citric Acid Cycle); a series of reactions that ultimately yields carbon dioxide and hydrogen as well as a little energy (2 ATP). Coenzyme-A is recycled in the process. The overall reaction can be summarised as above. The krebs cycle occurs in the '''mitochondrial matrix''' (the fluid inside the mitochondrion). ==Electron Transport Chain== '''Hydrogen + Oxygen → Water''' [image:http://i.imgur.com/GJd71q9.png?1] The hydrogens produced in the '''Krebs cycle''' are carried by a special carrier molecule known as '''NADH''' through the electron transport chain (also known as respiratory chain). This involves a series of reactions that take place on the surface of the '''cristae''' (the folds of the inner membrane). The folded structure of the cristae increases the surface area for these reactions to occur. In this process oxygen is added to the hydrogen to yield water and large amounts of energy (ATP). ==Aerobic Respiration Rate== Aerobic respiration is a series of chemical reactions. Each one of the reactions is catalysed by an enzyme. Enzyme activity is affected by a range of factors including: *'''pH''' *'''temperature''' *'''enzyme concentration''' *'''substrate concentration''' - the availability of the reactants (Glucose & Oxygen) *'''product concentration''' - the build up of respiratory products (Carbon Dioxide & Water) can limit aerobic respiration *'''enzyme cofactors''' - essential for transporting substrate molcules into enzyme active sites (e.g. NAD+ and CoenzymeA) *'''enzyme inhibitors''' ^For further detail see ''ENZYME ACTIVITY -FACTORS''^