Chapter 5 The Outsiders S.E. Hinton

Lipids include fats that are used for long-term energy storage! 71. Are lipids polar or nonpolar? What happens to lipids when they are placed in water? Lipids are nonpolar molecules. When placed in water, lipids tend to aggregate together and form structures such as micelles or lipid bilayers to minimize contact with water 72. Compared to carbohydrates, what is true about the ratio of carbon & hydrogen atoms to oxygen atoms? If a compound has more bonds, what can it store more of in those bonds? Compared to carbohydrates, lipids have a higher ratio of carbon and hydrogen atoms to oxygen atoms. If a compound has more bonds, it can store more energy in those bonds 73. Most lipids are made of ______fatty _____ acids. Describe their shape. What functional group is found on the head end of the molecule? Fatty acids are long hydrocarbon chains with a carboxyl group (-COOH) at one end. The shape of fatty acids is typically straight or slightly bent, depending on the degree of saturation of the carbon chain 74. Sketch these 2 fatty acids --- palmitic & linoleic. Circle the carboxyl group on the "head" of the molecule. Is this end polar or nonpolar? Will this end be attracted to or repelled by water? - Palmitic acid: Draw a long straight chain of carbon atoms with a carboxyl group (-COOH) at one end - Linoleic acid: Draw a similar carbon chain but with one or more double bonds present in the chain. Circle the carboxyl group. This end is polar. It is attracted to water 75. Are both ends of a fatty acid polar? Explain. No, only the carboxyl end of a fatty acid is polar 76. Hydophilic means water ___loving______. Which end of a fatty acid is hydrophilic. The nonpolar end of a fatty acid is said to be ______hydrophobic_____ or "water fearing". 77. Which end of a fatty acid chain WOULD dissolve in water? Which WOULDN'T? The carboxyl end of a fatty acid chain would dissolve in water, while the hydrocarbon chain wouldn't 78. In what type of fatty acid are there only single bonds in the carbon chain? Name one such fatty acid. In a saturated fatty acid, there are only single bonds in the carbon chain. An example is palmitic acid 79. What type of bond appears in an unsaturated fatty acid? Give an example of an unsaturated fatty acid. Go back to your fatty acid drawings in question 74 and put a box around the double bond in the unsaturated fatty acid. Unsaturated fatty acids contain one or more double bonds in the carbon chain. An example is linoleic acid. 80. Name the 3 groups of complex lipids. The three groups of complex lipids are phospholipids, glycolipids, and cholesterol 81. What makes up a triglyceride? What is the difference between a saturated & unsaturated triglyceride? A triglyceride is made up of one glycerol molecule bonded to three fatty acid molecules. The difference between saturated and unsaturated triglycerides lies in the presence of double bonds in the fatty acid chains. Saturated triglycerides contain only single bonds in the fatty acid chains, while unsaturated triglycerides contain one or more double bonds 82. What type of triglycerides tend to be solids at room temperature & why? Which are liquids & why? Saturated triglycerides tend to be solids at room temperature because the straight chains can pack closely together, leading to stronger intermolecular forces. Unsaturated triglycerides tend to be liquids at room temperature because the presence of double bonds introduces kinks in the carbon chain, preventing tight packing 83. What type of triglyceride would this of substance be --- vegetable oil? butter & shortening? Vegetable oil would consist mainly of unsaturated triglycerides, while butter and shortening would consist mainly of saturated triglycerides 84. What makes up a phospholipid? How are they different from triglycerides? What main part of a cell is made of phospholipids? A phospholipid is composed of a glycerol molecule bonded to two fatty acid molecules and a phosphate group. Phospholipids differ from triglycerides in that they have a phosphate group instead of a third fatty acid. The main part of a cell made of phospholipids is the cell membrane 85. What is meant by a lipid bilayer? What makes this such an effective barrier between the inside & the outside of the cell? A lipid bilayer is a structure formed by two layers of phospholipid molecules arranged with their hydrophobic tails facing inward and their hydrophilic heads facing outward. This arrangement creates an effective barrier between the inside and the outside of the cell due to the hydrophobic nature of the tails 86. Wax is another complex lipid. Describe its structure. Wax has a complex structure consisting of long-chain fatty acids linked to longchain alcohols or other hydrocarbons. It forms a protective, water-resistant layer on the surface of plants and animals 87. Waxes are highly _____hydrophobic___. Explain how plants make use of this property? animals? Plants use this property to prevent water loss from their surfaces, while animals use waxes to waterproof their fur, feathers, or outer coverings 88. What makes up steroids? To what group of organic compounds do steroids belong? How are they used in animals? Steroids are composed of four fused carbon rings. They belong to the group of organic compounds known as lipids. In animals, steroids serve various functions, including serving as signaling molecules, hormones, and components of cell membranes 89. Name a steroid made by the body & used by nerve cells. An example of a steroid made by the body and used by nerve cells is cholesterol Nucleic acids store genetic information for cells! 90. Give the name & abbreviation for 2 nucleic acids found in cells. Deoxyribonucleic acid (DNA), Ribonucleic acid (RNA) 91. DNA and RNA are both examples of __nucleic acids__ made of linked monomers called ____nucleotides____. The instructions in these molecules is used to make ___proteins___. 92. Name the 3 parts to a nucleotide then draw and label one. - A phosphate group A pentose sugar (either deoxyribose in DNA or ribose in RNA) A nitrogenous base (adenine, guanine, cytosine, thymine in DNA, or uracil in RNA)