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oDescribe the role of symbiosis in cellulose digestion. Name the principal energy storage carbohydrate molecules of plants and animals. Describe the building-block molecules, structure, and biological importance of fats, phospholipids, and steroids.
oSteroids: made of four fused rings. Their structure is a carbon skeleton. The importance is the managing of hormones.Distinguish between saturated and unsaturated fats. oSaturated fatty acid if there are no double bonds between carbon atoms composing a chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton SolidThe hydrocarbon chains of their fatty acids—the “tails” of the fat molecules—lack double bonds, and their flexibility allows the fat molecules to pack together tightly. oUnsaturated fatty acid has one or more double bonds with one fewer hydrogen atom on each double-bonded carbon Nearly all double bonds in naturally occurring fatty acids are cis bonds which cause a kink in the hydrocarbon chain whenever they occur Liquids PhospholipidsThey are a major constituent of cell membranesHave only two fatty acids attached to glycerol rather than three like fat molecules When phospholipids are added to water they self-assemble into double-layers structures called bilayers shielding their hydrophobic portion from water The phospholipid bilayer forms a boundary between the cell and its external environment (d) Phospholipids bilayer