Test 2 Essays - 11 Starting with a molecule of glucose...

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11) Starting with a molecule of glucose, trace the process by which energy within the bonds between the six carbon atoms is removed. Include glycolysis (in the presence and absence of oxygen), the Krebs cycle, and oxidative phosphorylation. Draw the complete structure of glucose pyruvate and lactate. Glycolysis : 1. Addition of one PO4 to glucose. 2. Addition of another PO4 to the other end of the 6 C intermediate. Phosphofructokinase is the enzyme? Precisely what does it do. This is regulated, rate-limiting step in glycolysis (see fig. 9.20). Question: Why add PO4 and use up ATP? To get the 6 carbon molecule into a form which will permit more efficient (less loss of energy to entropy) reactions in which the middle covalent bond is broken. 3. Split the central covalent bond --> 2 three-carbon fragments. 4. Rearrange 3 C molecules, strip off PO4s (fig. 9.7). 2PO4/each 3 C molecule--> 4 ATP = net of 2 ATP gained + 2 NADH(with 4 electrons) - these electrons have energy - how to get it - see fig. 9.15, electron transport – final product is pyruvate *Intermediate conversion of pyruvate to acetyl CoA Krebs cycle : . Goal - deliver energy of 2 covalent bonds from each 3 carbon fragment (pyruvate via acetylCoA) to ATP. 1. Transfer 2 carbon acetate to oxaloacetate (4C)--> citrate (6 C). 2. rearrange molecules in cycle with subsequent breaking of covalent bonds and obtaining some ATP directly and some energy in the form of electrons being carried by NADH (learn substance of figure 9.4) and FADH2. 3. produce a new molecule of oxaloacetate (4 C) to being cycle over again. Oxidative Phosphorylation: Electron Transport Chain - figs 9.13/14/15. Chemiosmotic Theory of Mitchell - a reverse proton pump Getting Energy from Electrons Carried by NADH and FADH2 1. Electrons spontaneously move from NADH and FADH2 to more electronegative cytochromes and similarly from one cytochrome to another--these electron carriers are arranged in order along the inner mitochondrial membrane as are the Krebs enzymes. 2. Pump H ions into intermembrane space, flow back along concentration gradient through ion channel/enzyme which uses concentration gradient energy to synthesize ATP, recall mitochondria structure or form provides function. 3. Oxygen is final electron acceptor and combines with H ions to form water. Fermentation: In the absence of oxygen (anerobic) glycolysis occurs but there is no final electron acceptor, so no NADH can be used so it is recycled by transferring it’s electons to pyruvate producing either lactate or ethanol. This produces a net of 2 ATP per glucose molecule. *Know structures of glucose, pyruvate and lactate.
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Essay # 12 Ethical analysis of providing health care: 1.) Health care should be available to all – it should be universal, continuous, affordable to individuals/families, and affordable and sustainable for society 2.) Health insurance should enhance health and well-being by promoting access to high-
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Test 2 Essays - 11 Starting with a molecule of glucose...

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