Adenosine triphosphate (ATP) is a organic chemical that is involved in many processes. It is found in cells of all living organisms as an energy-carrying molecule. ATP is a phosphorylated nucleotide that has a similar structure to DNA and RNA.About 30.5 kJ of energy is released by hydrolysis reaction of one phosphate group which is removed from each molecule in one mole of ATP. This reaction is catalysed by the enzyme called ATPases.
The figure below shows the structure of ATP:Aerobic and anaerobic respiration: Both aerobic and anaerobic respiration involve chemical processes which takes place in cell to produce energy which is used for cell metabolism. Aerobic respiration takes place in the mitochondria and requires glucose and oxygen,producing carbon dioxide, energy, and water as the result.C6H12O6 + 6O2 ? 6CO2 + 6H2OAnaerobic respiration produces less energy by using glucose in the absence of oxygen.
It takes place in the cell cytoplasm and produces lactic acid as a end product.C6H12O6 ? 2C3H6O3 The stages of aerobic and anaerobic respiration include glycolysis, krebs cycle and electron transport chain. Role of Coenzyme:Co-enzyme is a small, organic, non-protein molecule that helps enzymes to catalyse a reaction without been used up.
Glycolysis:Glycolysis is the first stage of respiration and does not require oxygen therefore this stage is anaerobic. It is a process in which one molecule of glucose split into two smaller molecules of pyruvate. At the end of glycolysis, the pyruvate molecule is formed which loses a molecule of CO2 and accept hydrogen from NADPH to produce ethanol. Ethanol can be produced by anaerobic respiration in organisms such as fungi (e.g yeast).
Pyruvate + reduced NAD ? ethanol + carbon dioxide + oxidised NADLactate is also produced by anaerobic respiration in animals to overcome the temporary shortage of oxygen. When oxygen is in short supply, NAD from glycolysis is used to form lactate. Each pyruvate molecule produced takes up 2 hydrogen atoms from NADH that is produced in glycolysis to form lactate. Pyruvate + reduced NAD ? lactate + oxidised NADWhen oxygen is available again, the lactate produced is oxidised back to pyruvate which can be further oxidised to produce glycogen to store in the liver or can be use to release energy. There are two stages of glycolysis; phosphorylation and oxidation. Phosphorylation: Phosphorylation is the process of adding phosphate group to a molecule. 2 moles of ATP are consumed for each mole of glucose.
The glucose ring is phosphorylated and the 2 phosphates are provided from 2 molecules of ATP to form a hexose phosphate. Hexose phosphate (glucose) is split using water (hydrolysis).2 molecules of triose phosphate and 2 molecules of ADP are created and 2 molecules of ATP are used up.Oxidation:Triose phosphates are oxidised to form 2 molecules of pyruvate.
2 reduced NAD (NADH + H+) is formed when coenzyme NAD+ collects the hydrogen ions.4 ATP are produced, but 2 were used at the start, so there’s a net gain of 2 ATP. https://dk-media.s3.
amazonaws.com/AA/AB/mrplowman/images/12148566/huge/Figure_04_02_02.jpg The link reaction:The link reaction takes place in the mitochondrial matrix and connects glycolysis to krebs cycle. It does not use up oxygen but requires the presence of O2. In the link reaction, pyruvate molecules are decarboxylated in the mitochondria. Decarboxylated is a loss of carbon dioxide molecule.
Pyruvate molecules are then oxidised and converted to acetylcoenzyme A ( acetyl CoA).