Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
THE MITOCHONDRIA A mitochondrion is a specialized site of aerobic respiration. Like chloroplasts, mitochondria also have their own DNA and ribosomes. They also have a large organization of membranes that provides surface area for reactions. Unlike chloroplasts, it is the inner membrane that provides this surface area, through many folds called cristae. https://www.youtube.com/watch?v=RrS2 uROUjK4 FROM CYTOPLASM TO MITOCHONDRIA Products from glycolysis (2 pyruvate and 2 NADH - what about ATP?) are first transported from the cytoplasm into the mitochondria through active transport. The pyruvate undergoes a reaction called Pyruvate Oxidation, under which the pyruvate is oxidized (and 2 more NAD+ are reduced to NADH). It loses a CO2 in the process and the remaining 2Carbon molecule is attached to Coenzyme A to produce a molecule called Acetyl CoA. Note this is the first time CO2 has been given off. (As this happens for each of the two pyruvates, this is 2 of the original 6 carbons found in glucose.) ACETYL-COA • Acety-CoA is a central molecule in energy production. • Can be used to create ATP or store fat • If body need energy Acyetyl-CoA will enter the Kreb’s cycle , transferring most of its energy to ATP. If the body doesn’t need energy, Acetyl Co-A is sent to an anabolic pathway that creates lipids as a way of storing large amounts of energy as fat. • All nutrients; proteins, lipids and carbohydrates are converted to acetyl-CoA and then channelled toward fat or ATP production depending on the energy needs of the body THE KREB’S CYCLE Also known as the citric acid cycle, this is a cycle that occurs in the mitochondrial matrix and incorporates Acetyl CoA in order to break it down and capture its biochemical energy. It is an 8 step pathway, and it occurs twice for every molecule of glucose (2 acetyl CoA molecules that result from it). IMPORTANT STEPS IN KREBS Important steps: 4C oxaloacetate reacts with 2C acetyl-CoA to produce 6C citrate Energy is harvested in steps 3, 4, 5, 6, and 8 For each acetyl CoA: 3 NADH, 1 GTP/ATP, and 1 FADH2 is produced. After step 8, the oxaloacetate has been recycled, and can be used again. ** In Step 5, ATP is formed by substrate level phosphorylation. • A Pi from the matric removes CoA from succinyl-CoA. • The Pi is then transferred to Guanosine diphosphate (GDP) forming GTP. • The Pi group condenses with ADP forming ATP. Overall, free energy is transferred from succinyl-CoA to ATP by a form of substrate level phosphorylation. FOLLOW THE CARBON By the end of Krebs cycle, all six carbon atoms of the original glucose molecule have been lost as CO2 (which will be released as waste). All that is left of the original glucose molecule is some free energy in ATP, NADH and FADH2. In your pods, draw the carbons at the beginning and ending of the three stages we’ve looked at so far; Glycolysis, Pyruvate Oxidation and Kreb’s Cycle. . https://www.youtube.com/watch?v=00jbG_cfGuQ&list=PLMjKVK0oPAVQ1CT XEhB9wFk3n4r4k9KC2 FOLLOW THE ENERGY In your groups, determine all the energy products that arise from the breakdown of glucose. What is our net energy production at this point?