<p>The Structure and Function of Macromolecules #1</p><p>Small and large molecules: Emergent properties and levels of biological organization The concept of emergent properties applies to water and relatively simple organic molecules. Each type of small molecule has unique properties arising from the orderly arrangement of its atoms. Another level in the hierarchy of biological organization is reached when small organic molecules are joined inside cells, forming larger molecules.</p><p>Macromolecule: A giant molecule formed by the joining of smaller molecules, usually by a condensation reaction. Polysaccharides, proteins, and nucleic acids are macromolecules.</p><p>The four main classes of large biological molecules The four main classes of large biological molecules are carbohydrates, lipids, proteins, and nucleic acids. Many of these cellular molecules are, on the molecular scale, huge. For example, the mass of a protein molecule may be over 100,000 daltons.</p><p>1- Most macromolecules are polymers, built from monomers</p><p>Polymer: A long molecule consisting of many similar or identical monomers linked together.</p><p>Monomer: The subunit that serves as the building block of a polymer.</p><p>The large molecules in three of the four classes of life′s organic compounds— carbohydrates, proteins, and nucleic acids—are polymers.</p><p>The Synthesis and Breakdown of Polymers</p><p>Monomers are connected by a reaction in which two molecules are covalently bonded to each other through loss of a water molecule; this is called a condensation reaction, specifically a dehydration reaction, because the molecule lost is water.</p><p>Polymers are disassembled to monomers by hydrolysis, a process that is essentially the reverse of the dehydration reaction.</p><p>Bonds between monomers are broken by the addition of water molecules, a hydrogen from the water attaching to one monomer and a hydroxyl group attaching to the adjacent monomer.</p><p>1 An example of hydrolysis working in our bodies is the process of digestion. (hydrolysis, absorption into the bloodstream for distribution to all body cells, assemble of new polymers by dehydration reactions)</p><p>The Diversity of Polymers</p><p>Each cell has thousands of different kinds of macromolecules; the collection varies from one type of cell to another even in the same organism.</p><p>Proteins, for example, are built from 20 kinds of amino acids arranged in chains that are typically hundreds of amino acids long.</p><p>The specific structures and functions of the four major classes of organic compounds found in cells:</p><p>2- Carbohydrates serve as fuel and building material</p><p>2</p>