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Lipids. Aim : What are the building blocks of lipids? Do Now : Identify the four major groups of organic compounds . Identify the process in which several monosaccharides form a polysaccharide (or disaccharide) chain of sugars? What is added/removed during this process?
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Aim: What are the building blocks of lipids? • Do Now: • Identify the four major groups of organic compounds. • Identify the process in which several monosaccharides form a polysaccharide (or disaccharide) chain of sugars? What is added/removed during this process? • What two types of atoms are always found in organic substances?
Lipids Lipids include: waxes, fats, and oils
Building Blocks • Fatty acids • Glycerol Glycerol
Lipids • Atoms: Carbon (C), Hydrogen (H), and Oxygen (O) • Lipid atom ratio: 1C: 4H:1 O • Nonpolar (will not mix with H2O- water is polar) Q: Which other organic compound is made up of C, H, and O atoms? Carbohydrates!
Functions Within Organisms • Energy storage (long-term) • Lipids store 2x as much energy as carbohydrates. • Insulation and protection • Fatty tissue cushions vital organs and helps insulate the body. • Makes up cell structures (Ex: cell membrane) PhospholipidBilayer Weddell Seal
Phospholipids • 2 fatty acids + 1 glycerol molecule • Cell membrane consists of 2 layers of phospholipids (lipid bilayer). • Forms a barrier (semi-permeable membrane)
Energy Storage • When food is scarce: animals break down fat molecules to release energy for life processes. • When food is plentiful: excess food is converted into fats for LONG-TERM energy storage in animals. • Plants: oils are stored in seeds to provide energy to start the growth of the new plant.
Water Barriers • Phospholipids • Hydrophobic region (water fearing) • Hydrophilic region (water loving) • Waxes- • thin layer covers stems and leaves of plants to prevent evaporation of water from plant cells. • Some birds coat their feathers in oil. Why?
Fatty Acids • Long unbranched carbon chains with a carboxyl (-COOH) at one end. • COOH = polar/hydrophilic • Hydrocarbon end = nonpolar/hydrophobic • Make up most lipids • Saturated- each C has 4 covalent bonds with 4 other atoms. • Unsaturated- C atoms are not bonded to 4 atoms. Instead, they form C=C bonds.
Triglycerides • Consist of three fatty acid molecules + 1 molecule of glycerol. • Saturated triglycerides- contain saturated fatty acids • Unsaturated- do not • High melting points • Saturated- Usually solid at room temperature (Ex: butter and fats in red meat). • Unsaturated- usually soft or liquid at room temperature.
