PLS 160 Biotechnology Exam 1 Study Guide

Review two of the four basic types of biomolecules: Carbohydrates, Proteins, Nucleic Acids, Lipids. Carbohydrates: Energy in the form of ATP. Proteins: Biological catalysts, transporters, receptors, structure, antibodies, muscle. Nucleic Acids: DNA for deoxyribonucleic acid and RNA for ribonucleic acid, information molecules. Lipids: Structural at the cellular level. Examples of carbohydrates and lipids in our daily lives: Carbohydrates: Sugars, Starch, Cellulose, Simple Sugars. Proteins: Enzymes, Amino Acids. Nucleic Acid: DNA, RNA, Nucleotides. Lipids: Fats, Oils, Glycerol, Fatty Acids. Molecules in the Cell: Carbohydrates Simple sugars are the smallest carbohydrates. Carbohydrates are the main source of energy from are food, or eg muscle contraction (ATP). Simple sugars can combine to form disaccharides such as sucrose (glucose +fructose), lactose (glucose + galactose). A large number of glucose molecules can be connected to form starch, cellulose, and glycogen. Carbohydrates also play a role in cell recognition, cell signaling, and cell adhesion. Carbohydrates: Summary Soluble in water, hydrophilic, they dissolve in water. Important source of energy in the cell. Plants use part of the glucose to grow and develop but store much of it in the form of starch which can be broken down by plants or animals for energy. If animals have too much glucose, they store it as glycogen, too much fructose is stored as fat. Molecules in the Cell: Lipids Insoluble in water, including fats. Oils, waxes, sterols, fat soluble vitamins. Function in structural components of cell membranes, energy storage, and signaling. Fats in animals and oils in seeds. Saturated Fatty Acids: Contain maximum number of Hs, form straight chains, solid at room temperature. Unsaturated Fatty Acids: Contain one or more double bonds, have a distorted structure, liquid at room temperature. Molecules in the Cell: Cholesterol Cholesterol is a sterol Is an important component of animal membranes, provides the correct fluidity. Substrate for many hormones, estrogen, testosterone, and cortisone. Humans get cholesterol in three different ways 1 Diet 2 Stored cholesterol esters, and 3 Synthesis Nearly all human tissues synthesize cholesterol Controlling Cholesterol in Humans HMG-CoA reductase is the rate limiting enzymatic step in cholesterol biosynthesis. Statins compete with HMG CoA. The end result is lower LDL (Low Density Lipoprotein), TG (Triglycerides) and total cholesterol levels as well as increased HDL (High Density Lipoprotein) levels. Lipoproteins enable transport of fat molecules and cholesterol, within the water around cells and within the water based bloodstream. Fructose, is it good for us? HFCS is in everything! HFCS 55 (used in soft drinks), is approximately 55% fructose, 42& glucose and 3% other carbohydrates. Estimates are that about of the modern diet come from fructose. When fructose enters the blood steam it does not stimulate insulin and so finds its way to the liver and is converted indirectly into fats which enter the bloodstream as triglycerides (TAGs).