Study Guide 8-10 Answers

Study Guide 8-10 - Answers to study guide 8-10 Lipids(Kopachik Questions Lipids 1 Describe the structure of a fatty acid Use the terms hydrocarbon

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Answers to study guide 8-10 Lipids (Kopachik) Questions: Lipids: 1. Describe the structure of a fatty acid. Use the terms hydrocarbon chain, single and double bonds, saturated and unsaturated, cis versus trans. How would the melting temperature of a fatty acid differ if it changed to be more unsaturated? How are fatty acids used for energy storage? Refer to Figs. 5.11 and 5.12 of the text. The hydrocarbon chains are usually 14-18 carbons long with either all single covalent bonds between the carbons (saturated) or at least one double bond (unsaturated). The three chains can be the same or different. The unsaturated fatty acids can be in the cis or trans isomeric configuration but each puts a bend in the chain making the Van der Waals interactions of chains from one triglyceride to another poorer than if there are straight chains. As a consequence the unsaturated fatty acids need less heat energy (lower melting point) to disturb their structure. Fatty acids in fat stores are the main molecules used to store energy (roughly twice as much kcal/mole versus sugars on a per gram basis). 2. Describe phospholipid structure and their function in cells. Use the terms glycerol, ester linkage, hydrophilic head group, hydrophobic tail, amphipathic, bilayer membrane. A phospholipid is similar to a triglyceride except that there are only two hydrocarbon chains linked to the glycerol molecule via the ester linkage. The other bond is to a phosphate group (which can be covalently bonded to an amino acid serine as well). These molecules are amphipathic in having a hydrophilic phosphate (or phosphoserine) head group and a hydrophobic hydrocarbon chain tail. As a consequence of this duality this roughly linear molecule when mixed with water has the head groups like to form H bonds with water but the tails pushed inside in bilayers thus making a membrane. Refer to Fig. 5.13 for a diagram. 3. How are cholesterol, and estrogen and testosterone related in structure. Why are these structures although chemically different from fats and phospholipids still considered lipids? Cholesterol (Fig. 5.15) and other structurally diverse hydrophobic molecules are
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This note was uploaded on 05/25/2011 for the course BS 111 taught by Professor Patterson during the Winter '05 term at Michigan State University.

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Study Guide 8-10 - Answers to study guide 8-10 Lipids(Kopachik Questions Lipids 1 Describe the structure of a fatty acid Use the terms hydrocarbon

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