End of Unit 3 Notes
End of Unit 3 Notes Bio 190
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This 4 page Class Notes was uploaded by Danielle Francy on Saturday April 2, 2016. The Class Notes belongs to Bio 190 at Towson University taught by Joseph Velenovsky in Fall 2015. Since its upload, it has received 11 views. For similar materials see Intro Biology for Health Professions in Biology at Towson University.
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Date Created: 04/02/16
Unit 3 Notes Stage 1: ● Glycolysis occurs in the cytoplasm ● Breaks glucose into two molecules of a three Carbon compound Stage 2: ● Mitochondria ● Pyruvate oxidized to a two Carbon compound ● Small amount of ATP made during glycolysis and citric acid cycle ● Main function is to supply third stage with electrons Stage 3: ● ETC and chemiosmosis ● ETC in inner mitochondrion membrane ● ***Most of the ATP from cellular respiration is from this stage ● It is called oxidative phosphorylation because of ADP and phosphorylation ● Coupling of ETC to ATP synthesis ● Pumping of hydrogen ions across inner mitochondrial membrane into inner membrane space ● Concentration gradient of hydrogen ions ● Potential energy of concentration gradient used to make ATP ● ***Peter Mitchell=nobel prize Fermentation: ● Does not require oxygen ● Glycolysis generates ATP ● Same exact glycolysis in the first stage of cellular respiration ● Net gain of 2 ATP ● Oxidizing glucose to two molecules of pyruvate ● Reduces NAD+ to NADH ● Cellular respiration per glucose 32 ATP ● Why do this? ● If oxygen is scarce, (exercise) keeps muscles contracting ● Many microorganisms are able to have enough energy with just glycolysis ● Hypoxic environment ● In order to oxidize glucose during glycolysis, NAD+ must be present as an electron acceptor. ● No issue during aerobic conditions ● Regeneration during ETC ● Fermentation represents an anaerobic path to recycling NADH back to NAD+ ● Recycle to perform more glycolysis and generate ATP Alcoholic Fermentation: ● Yeast normally use aerobic respiration but can survive in anaerobic environments ● Recycling of NADH ● Carbon dioxide and bubbles Lactic Acid Fermentation: ● NADH oxidized ● Pyruvate reduced ● Lactate (ionized form of lactic acid) ● Muscle cells in humans Energy Investment: Steps 13: ● A fuel molecule is energized, using ATP Step 4: ● A six carbon intermediate splits into two 3 carbon intermediates Energy Payoff: Step 5: ● A redox reaction generates NADH Steps 69: ● ATP and pyruvate are produced ● 6% of the energy a cell can harvest from a glucose molecule ● Two NADH molecules are 16% but their energy cannot be accessed unless oxygen is present ● Pyruvate is transported from cytoplasm because glycolysis takes place there ● Enters mitochondrion (oxidative phosphorylation and citric acid cycle) ● ***Pyruvate itself doesn’t enter citric acid cycle ● Must be modified ● 1 molecule of glucose2 molecules of pyruvateoxidized2 molecules acetyl Coenzyme A ● Carboxyl group removed ● 1st step where carbon dioxide is released ● ***“Arrow” = large multienzyme complex ● 3 reactions ● B vitamin Krebs Cycle: ● Hans Krebs ● Each turn of the cycle 1 ATP through substratelevel phosphorylation ● 3 NADH ● 1 FADH2 ● 2 molecules of acetyl Coenzyme A for each glucose ● Overall yield= enzymes located in mitochondrial matrix or embedded in the inner membrane Right side of the Cycle: ● Redox reactions ● Strip hydrogen atoms off of intermediates ● Intermediates lose carbon dioxide ● Iodized citric acid Left side of the Cycle: ● Enzymes rearrange chemical bonds ● One turn is considered complete whxaloacetateas been regenerated Equals: ● From one glucose molecule: ● 4 ATP SLP ● 10 NADH ● 2 FADH2 ● To access energy in NADH and FADH2, the ETC must happen ● Oxidation of these molecules drives phosphorylation of ADP Oxidative Phosphorylation: ● Arrangement in membrane ● Creates hydrogen ion concentration gradient ● Energy of gradient drives ATP synthesis ● Inner membrane ● Cristae (folds) increase surface area ● Space for thousands of the ETC ● Multiple ATP synthases ● I,II,III,IV= where carrier molecules live ● Bind and release electrons in redox reactions transport between complexes ● I,III,IV use energy from electron transfers to transport hydrogen ions against their concentration gradient ● From matrix to inner membrane space ● Built into inner membrane mitochondrial membrane ● Hydrogen ions driven through a channel in ATP synthase ● Spinning a component of ATP synthase ● Activates catalytic sites that attach phosphate groups to ADP forming ATP ● ATP synthases act like miniature turbines Biosynthesis: ● Excess of certain amino acid ● Turned off by feedback inhibition ● Also controls cellular respiration ● Based on ATP quantity ● Inhibits early enzyme in glycolysis ● Enzyme activated by ATP