Organic Macromolecules: Lipids

I. Introduction to Macromolecules macromolecules A. Many of the organic molecules within the human body are classified as macromolecules. 1. The term “macromolecule” literally means “giant molecule” macro- (“macro-” = giant) polymers 100’s- 1000’s monomers 2. Macromolecules are often referred to as polymers which means that they are formed by joining together many (100’s- 1000’s) of repeating units called monomers.

II. Structures of Lipids long chains large, globular molecules A. Most macromolecules join together to form long chains but lipids can join together to form large, globular molecules. type of lipid you are referring to 1. The composition and conformation of lipids depends on the type of lipid you are referring to

are composed of one glycerol molecule and three fatty acid chains Triglycerides are composed of one glycerol molecule and three fatty acid chains have one glycerol molecule, two fatty acid chains, and a charged/polar phosphate group Phospholipids have one glycerol molecule, two fatty acid chains, and a charged/polar phosphate group can form long chains or twist in on themselves to form rings Steroid Lipids can form long chains or twist in on themselves to form rings

III. Functions of Lipids store energymake the primary structure of plasma membranesbe a primary component of hormonesprovide pigmentstabilize plasma membranes A. Lipids tend to either store energy, make the primary structure of plasma membranes, be a primary component of hormones, provide pigment, or stabilize plasma membranes. triglycerides B. Lipids that primarily store excess energy are triglycerides a simple lipid in which three fatty acids are combined with one molecule of glycerol Triglycerides – a simple lipid in which three fatty acids are combined with one molecule of glycerol

An illustration of a triglyceride molecule would be: Glycerol

the different types of fats found in our foods. 1. Triglycerides are the different types of fats found in our foods. solidsliquids 1. Triglycerides can either be solids or liquids at room temperature (20 O C) fats have saturated fatty acid chains attached to glycerol. a. Triglycerides (fats) that are solid at room temperature have saturated fatty acid chains attached to glycerol.

a fatty acid molecule consisting only of carbon and hydrogen atoms with NO double bonds between any of the carbon atoms Saturated Fatty Acid Chain – a fatty acid molecule consisting only of carbon and hydrogen atoms with NO double bonds between any of the carbon atoms *This configuration maximizes the number of hydrogen atoms bound to carbon atoms* b. Oils unsaturated fatty acids b. Oils are liquid at room temperature and are considered to be unsaturated fatty acids. a fatty acid molecule consisting only of carbon and hydrogen atoms with one or more double bonds between any of the carbon atoms. Unsaturated Fatty Acid chain – a fatty acid molecule consisting only of carbon and hydrogen atoms with one or more double bonds between any of the carbon atoms.

Saturated Fatty Acid ChainUnsaturated Fatty Acid Chain

phospholipids C. Lipids that make up the basis of biological membrane are phospholipids. cellular materials that have a phosphorus containing component that can dissolve in organic solvents Phospholipids – cellular materials that have a phosphorus containing component that can dissolve in organic solvents

they form a two-layer membrane in cells and cellular organelles. 1. Because of the two unique parts of the phospholipid they form a two-layer membrane in cells and cellular organelles. “water loving” portion of a phospholipid that is polar and dissolves in water Hydrophilic Polar Head – “water loving” portion of a phospholipid that is polar and dissolves in water “water fearing” portion of a phospholipid that is nonpolar and does not dissolve in water Hydrophobic Nonpolar Tail – “water fearing” portion of a phospholipid that is nonpolar and does not dissolve in water

An illustration of phospholipids and how they form membranes would be: Hydrophilic Hydrophobic

hormones pigments D. Lipids that are a part of hormones or pigments form long chains or rings or carbon and hydrogen atoms. carotenoids 1. Pigments in plants and animals come from carotenoids. a yellow, orange, or red lipid pigment commonly found as an accessory pigment in photosynthesis Carotenoids – a yellow, orange, or red lipid pigment commonly found as an accessory pigment in photosynthesis specifically  - carotene, can be broken down into two vitamin-A molecules which are the building blocks for rhodopsin, a protein that helps our eyes interpret light. a. In humans carotenoids, specifically  - carotene, can be broken down into two vitamin-A molecules which are the building blocks for rhodopsin, a protein that helps our eyes interpret light.

steroids 2. Lipids made up of carbon atoms that are bonded in the shape of a ring are called steroids. any of numerous lipids based on a 17-carbon atom ring system Steroids – any of numerous lipids based on a 17-carbon atom ring system hormones a. Many steroids make up hormones.

plays a role in regulating the digestion of carbohydrates and proteins, salt and water balance, and sexual development. It also plays a role in handling stress. Cortisone plays a role in regulating the digestion of carbohydrates and proteins, salt and water balance, and sexual development. It also plays a role in handling stress. regulates sexual development in male/female vertebrates Testosterone/Estrogen regulates sexual development in male/female vertebrates

E. Another common steroid that helps to stabilize plasma membranes is cholesterol. making testosterone, several other steroid hormones, and for the bile salts that aid in the digestion of fats. It is also found holding plasma membranes together. Cholesterol is the starting material for making testosterone, several other steroid hormones, and for the bile salts that aid in the digestion of fats. It is also found holding plasma membranes together.

What is too much cholesterol?: High Density Lipoprotein is considered “good cholesterol” picks up extra cholesterol and delivers it to the liver to be metabolized. [Want to raise this number] HDL: High Density Lipoprotein is considered “good cholesterol” picks up extra cholesterol and delivers it to the liver to be metabolized. [Want to raise this number] Low Density Lipoprotein is considered “bad cholesterol” transports cholesterol in the blood and may lead to atherosclerosis (hardening/narrowing of the arteries) [Want to lower this number] LDL: Low Density Lipoprotein is considered “bad cholesterol” transports cholesterol in the blood and may lead to atherosclerosis (hardening/narrowing of the arteries) [Want to lower this number]

HDL/LDL Ratio being researched as an indicator for health disease. *Currently it is believed it should be >0.3 (ideally it would be >0.4)