Aerobic and anaerobic respiration

• All organisms respire in order to release energy to fuel their living processes.
• The respiration can be aerobic, which uses glucose and oxygen, or anaerobic which uses only glucose.
• A substance broken down by respiration to release energy is known as a respiratory substrate.
• Glucose is the molecule normally used for respiration and is the main respiratory substrate.
• Chemical substances are oxidised by the addition of oxygen, removal of hydrogen or the removal of electrons to release their energy.
• The word equation for aerobic respiration is: glucose + oxygen → carbon dioxide + water + energy released.
• The chemical symbols for glucose and oxygen are C 6 H 12 O 6 and 6O 2 respectively.
• The chemical equation for aerobic respiration is: C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + energy released.
• Respiration is a series of reactions, but this summarises the overall process.
• The first stages of respiration occur in the cytoplasm of cells, but most of the energy released is in the mitochondria.
• Mitochondria are structures in the cytoplasm of all cells where aerobic respiration takes place.
• Some organisms and tissues can continue to respire if the oxygen runs out, using the process of anaerobic respiration.
• Without oxygen, anaerobic respiration produces lactate.
• Some plants, and some fungi, such as yeast, can respire anaerobically, it's preferable to release less energy but remain alive.
• Aerobic respiration involves the oxidation of glucose, anaerobic respiration does not.
• Aerobic respiration produces carbon dioxide and water, anaerobic respiration produces lactic acid.
• The products of aerobic respiration still contain energy, the products of anaerobic respiration do not.
• Anaerobic respiration occurs only in the cytoplasm of cells.
• The products of aerobic respiration still contain stored chemical energy, the products of anaerobic respiration do not.
• The glucose in muscle is converted to lactic acid, a toxic chemical produced during anaerobic respiration.
• Aerobic respiration is present when there is the presence of oxygen, anaerobic respiration is absent or in short supply.
• Human muscle can respire anaerobically for short periods of time, even though the process is relatively inefficient, it's better to continue respiring and be able to run away from danger or run a race.
• Glucose in yeast cells is converted to carbon dioxide and ethanol, which we refer to simply as 'alcohol', glucose → ethanol + carbon dioxide + energy released.
• The amount of energy released in aerobic respiration is relatively large, in anaerobic respiration it's a small amount, but quickly.