Respiration

• What are the stages of aerobic respiration? 1 - Glycolysis 2 - Link reaction 3 - Kreb Cycle = oxidative phosphorylation
• what happens in Glycolysis? 1 - ATP is used to convert glucose (6c) into glucose phosphate 2 - ATP is used again to convert glucose phosphate into fructose phosphate 3 - fructose phosphate then splits into 2X triose phosphate (3c) 4 - the enzyme dehydrogenase then breaks a hydrogen off triose phosphate and adds to NAD to make NADH2 and the triose phosphate is convered to pyruvate. the breaking of H2 off the triose phosphate gives enough energy for 2ADP + 2Pi = 2ATP
• what happens in the link reaction? 1 - decarboxylase catalyses release of CO2 from pyruvate (3c) and dehydrogenase breaks H2 off pyruvate and adds to NAD to make NADH2 so pyruvate is converted to acetyl (2c)
• what happens in the Kreb cycle? 1) acetyl Coenzyme A is converted into 6C citric acid 2) decarboxylase catalyses removal of CO2 from the citric acid, and dehydrogenase breaks H2 off of the citric acid and adds it to NAD to form NADH2. 6C citric acids then becomes a 5C 3) the same happens again and it becomes 4C 4) this time ATP is also produced and NADH2 still 4C 5) the same again but with FAD to form FADH2 6) the same again and the cycle repeats from the start
• what happens in oxidative phosphorylation? 1) proton pumps in the inner mitochondrial membrane pump H+ into the inner membrane space from the matrix creating a concentration gradient between the inner membrane space and the matrix. 2) H+ then goes down the stalked particle down the concentration gradient into the matrix this energy is used by ATP synthetase to produce 1 ATP from 2 H+ needed
• what happens if there is no oxygen? the reduced NAD and reduced FAD cannot be reoxidised and therefore made available to pick up more hydrogen atoms
• what happens in anaerobic respiration? 1) only glycolysis can take place then either lactic acid fermentation or alcoholic fermentation takes place
• what happens in lactic acid fermentation? 1) glycolysis 2) dehydrogenase breaks off H2 from NADH2 and adds it to pyruvate forming lactic acid
• what happens in alcoholic fermentation? 1) glycolysis 2) CO2 is removed from the pryuvate and forms ethanal 3) dehydrogenase removes H2 from NADH2 and adds to ethanal to form ethanol
• how can lactic acid fermentation be reversible? if more oxygen becomes available, the amount of oxygen needed to remove the lactic acid is called oxygen debt