August 29th, 2013MSCI 311Energy Metabolism - If oxygen is present, why does aerobic respiration take place instead of anaerobic with other molecules? Aerobic respiration releases the most amount of energy. Entropy always increases, so more energy is released means more entropy, means more ATP is produced.- What is all this energy used for in the cell?- How does cell harvest this energy to do work?- Digestive process in cell: ingest by phagocytosis, moved through cell via cytoskeleton, fuse with lysosome, enzymes from lysosomes break it down into constituent parts, broken down parts are used to drive ATP production- Molecules involved in respiration: glucose, fructose, pyruvate, acetyl-CoA, citric acid, oxaloacetate, ATP - Aerobic and anaerobic both start with glycolysis in the cytoplasm, aerobic continues on to mitochondria- Glucose + oxygen ----> carbon dioxide + water- Glycolysis happens in everything- Energy requiring steps of glycolysiso Glucose to PGAL- Energy producing stepso Produces 4 ATP, two reduced coenzymes (yields two ATP)o Left with two pyruvate=end product of glycolysis- Glycolysis: one molecule of glucose is transformed into 2 molecules of pyruvate, yielding two net ATP- To begin Kreb’s cycle we must move into the mitochondrion- Mitochondrion: outer membrane (two layers=inner/outer compartment to max SA for Rx, inner membrane)- Krebs cycle/citric acid cycle: go through twiceo 2 pyruvates enter=get broken down and end up giving off six CO2o NAD+ takes pyruvate and forms acetyl-CoA, then forms citric acid…- Electron Transfer Chaino Energy input splits Hydrogen in protons and electronso Electrons transferred through an electron transfer system with use of proteinso Some released energy is used to make ATPo Spent electrons and free oxygen form watero Occurs in in membrane of mitochondriono Energy from transferring electrons is used to pump H ions across membrane, forms a H concentration gradient, H goes through ATP synthase - We get 32 ATP from e- transport chain, 2 from krebs, and 2 from glycolysis- Understand where ATP are coming from, know details for exams, be able to fill in a chart of the processes- Oxygen is the final acceptor of electrons because it produces the most amount of energy compared to other possible electron acceptors - Blue crabs are decliningo Pathogens and pollutants impair blue crab metabolic processes (aerobic respiration)o A certain kind of natural bacteria impairs crab ability to incorporate oxygen in metabolismo Too much glucose building up, not enough oxygen to break it down-not producing ATP they need, not enough energy to grow/reproduceo They breath enough to stay alive, not enough oxygen getting into actual tissues to break down glucose- Anaerobic respirationo Alcoholic fermentation Begins with glycolysis, then produces ethanol by adding water to the pyruvate, releases carbon dioxide to form 2 acetaldehyde, e-, H from NADH form two ethanolo Lactate fermentation-yogurt, cheese, sore muscles Begins with glycolysis, pyruvate pick up H and e- from NADH toform 2 lactateo Both produce way less energy (only 2 molecules of ATP for each glucose molecule)o Some anaerobes undergo e- transfer but final e- acceptor isn’t oxygen, so anaerobic respiration by bacteria uses other e- acceptors- More complex/diversified organisms are able to form once oxygen and aerobic respiration occurred because there’s much more energy to produce bigger and more organisms (more energy to grow/reproduce)- Overall- size of fish becomes smaller and