Week 4 Review Sheet answers

Week 4 Review Sheet answers - Final Review Sheet Week 4...

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Final Review Sheet – Week 4 Lecture 9 The first part of this was included in the first midterm (and can be found at the end of Lecture 8). We will begin material for the second exam with the section of Chapter 3 on metabolism. Main Points: “Metabolism” is the entire picture, including synthesis of molecules (anabolism) and breakdown (catabolism). Catabolism generally releases energy, anabolism requires it (think of what these mean with respect to the entropy of the system). Catabolism involves three levels: breakdown of large molecules (polysaccharides, proteins, fats) into smaller components. This is what goes on in digestion and is necessary for the materials to be taken up by the cells. The second step is breakdown of these molecules to make a common product, acetyl CoA. The third is the entry of the acetyl CoA into the tricarboxylic acid cycle (TCA cycle, Krebs cycle), which ultimately results in production of ATP. In addition to providing energy, catabolism of large molecules produces building blocks from which the cell makes its own macromolecules. Understand the definitions of oxidation and reduction. Keep in mind that for something to be oxidized, another molecule must be reduced. You should be able to look at a reaction and tell which molecule is being oxidized and which reduced. Carbon is in its most reduced form when bound to four hydrogens. It is in its most oxidized form as CO 2 . Glucose catabolism releases large amounts of energy and involves several steps. Glycolysis, in the cytoplasm, and the TCA cycle, coupled with electron transport and oxidative phosphorylation, which complete the process in the mitochondrion (in a eukaryotic cell. In a prokaryotic cell the TCA cycle goes on in the cytoplasm). Step 1 is glucose + ATP → glucose-6-phosphate + ADP. This reaction is important for several reasons. One is that it is the first step in the process of glycolysis. Another is that it maintains the glucose gradient such that the inside concentration is always lower than the outside and it also keeps it from going back out because G-6-P can’t go through the glucose transporter. Step 1 is irreversible because the free energy released by splitting G-6-P is not sufficient to make ATP from ADP.
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Final Review Sheet – Week 4 Sample Questions: 1. Fats have more energy per gram than sugars. Why is that? It is due to the fact that in fats, the carbon is in its most reduced form, which is
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Week 4 Review Sheet answers - Final Review Sheet Week 4...

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