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Chapter 2. The Chemistry of Life. The Atom. The Atom on Motion. Terminology. Element – A pure substance that consist entirely of one type of atom Ex. Gold (Au) Isotope – Atoms of the same element that differ in the number of neutrons they contain Ex. Carbon-12 and Carbon-14
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Chapter 2 The Chemistry of Life
Terminology • Element – A pure substance that consist entirely of one type of atom • Ex. Gold (Au) • Isotope – Atoms of the same element that differ in the number of neutrons they contain • Ex. Carbon-12 and Carbon-14 • Compound – A substance formed by the chemical combination of two or more elements • Ex. Salt (NaCl) • Molecule – Two or more atoms held together by covalent bonds • Ex. Water (H2O)
Atomic Bonding • Ion – Any atom with a charge due to the loss or gain of electrons • Ex. Hyrdoxide (OH-) • Ionic Bond – a bond characterized by the TRANSFER of electrons from one atom to another • Covalent Bond – a bond characterized by the SHARING of electrons between two atoms
van der Walls Forces • Slight attraction that develops between oppositely charged regions of nearby molecules
Skill Check • What is the biggest difference between an electron and a proton or neutron, other than charge or location? • Where are protons and neutrons located in an atom? • What is another name for the outermost electron shell? • What is the difference between an ionic bond and a covalent bond? • Why can geckos scale walls like Spider-Man?
Properties of Water • Universal Solvent – because water is a polar molecule (Solution, solute, solvent) • Cohesion – because of hydrogen bonding (water molecules like to stick together) • Adhesion – Water likes to stick to other things (meniscus) • Surface Tension – Top layer of molecules is more attracted to itself than air • High Heat Capacity – Temperature stabalizer, not a good conductor
Acids, Bases and pH • Acid – compound that releases a proton (H+) when it dissolves in water • Base – compound that takes up a proton (H+) when it dissolves in water • pH – a universal scale measuring the H+ concentration of solutions
Chapter 2.3 Carbon Compounds
Skills Check • What is an element? • What is the difference between a molecule and a compound? • What is a covalent bond? • What is are the outermost electrons called? • What is the Octet Rule?
Intro to Organic Chemistry • Organic Chemistry is a branch of science dedicated solely to the study of the carbon atom. • Carbon atoms have 4 valence electrons. • Carbon can form millions of different molecules, in a variety of shapes.
Intro to Macromolecules • Macromolecules are giant molecules made from hundreds or thousands of smaller molecules. • The smaller molecules are referred to as monomers. • Monomers join together to make polymers. • The process by which monomers join to make polymers is called polymerization.
Macromolecule Groups • Carbohydrates • Lipids • Nucleic Acids • Proteins
Group Time • Please split up into 4 groups. • You will be handed a worksheet pertaining to one of the four groups of macromolecules. • Using your book, take a few minutes to finish the worksheet as a group. • Nominate one or two presenters to come up to the board and teach the rest of the class what you have learned about your macromolecule.
Macromolecule Animation • http://learn.genetics.utah.edu/content/begin/cells/scale/
Chapter 2.4 & 2.5 Chemical Reactions and Enzymes
Chemical Reactions • Chemical Reaction – Process that changes one set of chemicals (the reactants) into another set of chemicals (the products) • Ex. 2H + O H20 • Oxidation reactions are slow, other reactions are faster (think explosions) • All chemical reactions involve the breaking and forming of bonds
How do Chemical Reactions Start? • Some are spontaneous • Spontaneous reactions release energy
How do Chemical Reactions Start? • Some are not • These reactions require the input of energy to begin (referred to as Activation Energy)
Where Can We Get Some Activation Energy? • From Catalysts, of course! • Any substance that speeds up a reaction is called a Catalyst. • Examples of catalysts:
Enzymes • Enzymes are proteins that act as catalysts inside the body. • Enzymes are specialized to work best at a certain pH and a certain temperature. • Every enzyme has an “active site” where substrates can attach or bind