Chapter 4 Nutrition Metabolism Enzymes Malnutrition A medical condition resulting from the lack of essential nutrients in a diet Malnutrition around the world Often but not always associated with starvation Number one killer of children around the world More die each year than the number who die from AIDS tuberculosis and malaria Most deaths occur in sub Saharan Africa combined Why does lack of food lead to malnutrition Poverty is endemic Food is scarce most of the year Food contains nutrients Nutrients The chemical building blocks our bodies need to live grow and repair themselves Provide energy Powers our activities Energy is the ability to do work Helps build complex muscles Macronutrients Nutrients that organisms ingest in large amounts to maintain health Carbohydrates Foods rich in proteins meats legumes dairy Foods rich in fats dairy meats oils Foods rich in carbohydrates fruits and vegetables grains and legumes beans and lentils Proteins lipids fats Food provides macronutrients Foods contain mixtures of macronutrients A varied diet must include Vegetables Oils Grains Meat Dairy products Many foods contain all three types of macronutrients The proportion of each one varies in different foods Animal products contain more protein per gram than carbohydrate Most plant products contain more carbohydrate than protein Provide our cells with building blocks Macronutrients are large molecules Cannot be used directly from diet Digestion Must be broken down into smaller units Use subunits as building blocks or energy Broken down into amino acids Proteins Use to assemble new proteins that have many different functions in the body Carbohydrates Broken down into simple sugars Used to build cell surface markers energy storage molecules Lipids Fats Broken down into fatty acids and glycerol Used to build molecules that form cell membranes Nucleic Acids Essential Nutrients Are not macronutrients Provided in small amounts Broken down into individual nucleotides Use to build DNA and RNA Cells cannot synthesize them Nutrients that must be obtain through diet Essential amino acids 20 amino acids 9 cannot be synthesized Foods that contain all the nutrients necessary Ready to use food therapeutics RUTF Complete foods Malnutrition Results from chronic undereating especially up to two years of age All starts with digestion The child lacks nutrients necessary for the chemical reaction of growth and development What is digestion can use them Metabolism Process of breaking down huge food molecules into smaller pieces so that our body Series of chemical reactions to break the bonds that hold food molecules together Starts in our mouths and continues throughout the digestive system All the chemical reactions occurring in the body Catabolic reactions break down larger structures into smaller ones bond breaking Anabolic reactions build new structures from smaller subunits bond building Requires the assistance of helper molecules called enzymes enzymes Micronutrients Enzyme protein the speeds up a chemical reaction Substrate molecule to which an enzyme binds and on which it acts Active site part of an enzyme that binds to the substrate Catalysis the process of speeding up the rate of a chemical reaction e g by Activation energy energy required for a chemical reaction to proceed Organisms also need micronutrients small amounts to maintain health Inorganic micronutrients required to activate an enzyme Zinc copper iron Small organic molecules required to activate enzymes Vitamins act as coenzymes Minerals inorganic elements required by organisms for normal growth Nutrients including vitamins and minerals that organisms must ingest in Minerals act as cofactors reproduction and tissue maintenance reproduction and tissue maintenance Play structural and functional roles in the body For example calcium iron potassium zinc A balanced diet Vitamins organic molecules required in small amounts for normal growth Most nutritionists recommend that fruits vegetables and whole grains make up the largest portion of our diet Summary Food is a source of nutrients Nutrients provide the chemicals required to build and Nutrients required in large amounts are called macronutrients nutrients required in Enzymes are proteins that accelerate the rate of chemical reactions by binding maintain cells and tissues and furnish cells with the energy needed to function smaller amounts are called micronutrients specifically to substrates and reducing the activation energy necessary for a reaction to occur reactions Micronutrients such as minerals and vitamins are important coenzymes Enzymes mediate both bond breaking catabolic and bond building anabolic Many enzymes require small helper chemicals known as cofactors to function Chapter 5 Energy Flow and Photosynthesis Using algae to make fuel energy Algae are best known for the green red or brown hues Also have ability to capture energy of sunlight and convert it into usable forms of Much is in the form of oils ideally suited to making fuel Demand for oil will increase over the next 25 years Sources of oil are finite Takes millions of years to replenish Fossil fuels are limited U S energy consumption The United States is the largest consumer of fossil fuels New energy sources being developed to reduce our demand Biofuels Renewable fuels made from living organisms In 2012 more than 150 companies were dedicated to making fuel from algae Energy Basics Energy capacity to do work Includes processes such as building complex molecules and moving substances in and out of the cells Without a source of energy all life on Earth would stop Humans and other animals obtain energy by eating food Energy cannot be created Chemical Energy Potential energy stored in bonds of biological molecules Break bonds to release stored energy to do work Energy is conserved Algae and plants get energy from the sun Trap energy and store it in molecules Biofuel produces high in chemical energy Energy cannot be created or destroyed Energy can change form Conservation of energy Potential energy stored energy in the chemical bonds Kinetic energy the energy of motion or movement Heat the kinetic energy generated by random movement of molecules or atoms Example 1 A cyclist takes in potential chemical energy in the form of an energy 2 The cyclist digests the bar chemical bonds are broken down and stored bar potential energy is released As the cyclist climbs a hill potential energy is transformed into kinetic Energy