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Chemistry of Life Chapter 3 Section 1: Matter and Substances Atom – smallest unit of matter 3 Particles: Protons (+), Neutrons (0), Electrons (-) Smartboard Tutorial Element – a substance made up of atoms that cannot be separated Isotopes – atoms of an element that have different #’s of neutrons Compound – a substance made up of bonded atoms of 2 or more different elements Valence Electrons – outermost electrons Molecule - group of atoms held together by covalent bonds 2 Types of Chemical Bonds 1. Covalent – sharing valence electrons Ex. Water (H2O) 2. Ionic – transferring electrons Ex. Table Salt (NaCl) Polarity – describes the positive or negative state of a molecule Polar – Water, salt, sugar (easily attracted to each other) Nonpolar – oil, grease Solubility – capable of being dissolved Hydrogen Bonds – important in the bonding of living things Section 2: Water and Solutions 4 Properties of Water 1. Density – water is less dense as a solid than a liquid (hydrogen bonds create empty spaces) 2. Water absorbs and retains heat (hydrogen bonds constantly break & form) 3. Cohesion - water molecules stick to each other 4. Adhesion – water molecules stick to other polar substances Solution – an evenly dispersed mixture of 2 or more substances; some solutions change the balance of ions (charged particles) Acid – any cmpd. that increases the # of hydronium (H+) ions when dissolved in water Example: HCl in your stomach Base – any cmpd. that increases the # of hydroxide (OH-) ions when dissolved in water Example: ammonia (NH4+) pH – measure of how acidic or basic a solution is Buffer – substance that reacts to prevent a pH change in a solution Section 3: Carbon Compounds Building Blocks of Cells include: 1. Carbohydrates – molecules made of sugars Used for: sources of energy, structural materials, cellular identification 2. Lipids – fat molecules Used for: storing energy and controlling water movement 3. Proteins – molecule made up of amino acids Used for: provide structure/support, enable movement or communication, and carry out chemical reactions 4. Nucleic Acids – an organic cmpd. made of two chains of sugar and carry genetic information Used for: store and transmit hereditary information ATP – Adenosine triphosphate; acts as the main energy source for cell processes Section 4: Energy and Metabolism Conservation of Mass – mass is neither created or destroyed, only changed forms Conservation of Energy – energy is neither created or destroyed, only changed forms Chemical Reactions include: Reactant – substance that is changed in a chemical reaction Product – new substance formed in a chemical reaction Activation Energy – minimum amount of energy required to start a chemical reaction Enzymes – molecules that speed up a reaction sites – region where the reaction takes place Substrates – shape of active site that reactors will bind to Active Enzyme Action: 1. Substrates bind to enzyme’s active site 2. The enzyme changes shape, which catalyzes (speed up) the reaction 3. Product is released when the reaction is complete Metabolism – the sum of physical and chemical processes in an organism