homework+molecules+of+life+2.3

Monroe Stadler 8-19-08 Dr. Field

Human Biology Homework Define...organic molecules Organic molecule – A molecule hat contains carbon and hydrogen 1. What are the four classes of molecules unique to cells? Carbohydrates Lipids Proteins Nucleic acids 2. What type of recation occurs during the synthesis of macromolecules? Dehydration reaction 2.4 Carbohydrates (p. 28-29) Define... Monosaccharide A carbohydrate that has three to seven carbon atoms Disaccharide When two monosaccharides join together by a dehydration reaction Glucose Hexose used as an immediate source of energy, 6-carbon sugar Polysaccharide Macromolecules that contain many glucose units Starch Readily stored forms of glucose in plants and animals Glycogen Readily stored form of glucose in plants and animals Cellulose Used as fiber in the digestive tact found in plant cell walls 1. What is the usual function of carbohydrates in humans? Used for quick and short-term energy storage 2. What is the difference between a simple carbohydrate and the various complex carbohydrates? Simple carbohydrates have low carbon atoms while complex carbohydrates have many glucose units 3. Of what benefit is fiber in our diet? Can prevent heart disease 2.5 Lipids 1. Define saturated fats, unstaturated fat, and trans fat. Saturated fats have no double bonds between the carbon atoms the fat carbon chain has all the hydrogen’s it can hold Unsaturated fat have double bonds in the carbon chain wherever the number of hydrogen’s is less than two per carbon Trans fats fats in vegetable oils that are partially hydrogenated to make them semi-solid 2. What is the main function of fats and oils and what are they composed of? Fats are usually of animal of animal origin and are solid at room temperature. There uses include long term energy storage, insulation and it forms a protective cushion around major organs. Oils are liquids at room temperature and are usually of plant origin. 3. What are the uses of phospholids and steroids in the body? The primary components of cellular membranes. They form the so-called polar head of the molecule 2.6 Proteins (p. 32-34) Define peptide bond, and denaturation A peptide bond is the resulting bond of two amino acids. Denaturation when proteins undergo an irreversible change due to extreme heat or change in pH 1. What are the major functions of proteins in an organism? Antibodies are proteins, hormones are regulatory proteins they make nails and collagen. Muscle contains protein 2. How does an amino acid get its name? One of the groups of atoms that forms amino acids comes from the amino group while the other one comes from the acid group the third group is the “r” group 3. How does the shape of a proein relate to its function. A protein cannot function regularly if it undergoes denaturation and changes shape