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The Chemistry of Life – Matter and Energy. Chapter 2. The Nature of Matter. Atoms Basic unit of matter Incredibly small (you could line up 100 million acros the width of your little finger) Made of three particles Protons – positive charge, located in nucleus
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The Nature of Matter • Atoms • Basic unit of matter • Incredibly small (you could line up 100 million acros the width of your little finger) • Made of three particles • Protons – positive charge, located in nucleus • Neutrons – no charge, located in nucleus • Electrons – negative charge, located around nucleus • Usually electrically neutral (protons=electrons)
The Nature of Matter • Elements and Isotopes • Element – pure substance, only one type of atom • Atomic number – number of protons in nucleus • Isotope – atoms of the same element that have different numbers of neutrons • Mass number – number of protons and neutrons in nucleus • All isotopes of an element have the same chemical properties • Radioactive isotopes – nuclei are unstable and breakdown • Used for geologic dating, cancer treatment, protection from bacterial outbreak in food etc
The Nature of Matter • Chemical Compounds • A substance formed by chemical combination of two or more elements • Physical and chemical properties are different from the elements it is made of
The Nature of Matter • Chemical bonds • Created by interaction between electrons • Two major types • Ionic – occur when electrons are transferred, causes an electrically charged atom (ion) • Covalent – occurs when electrons are shared • Creates a molecule
Properties of Water • The Water Molecule • Found in an liquid state all over the planet • Polarity – unequal attraction between the shared electrons • Hydrogen bonding – attraction between molecules because of polarity • cohesion • Adhesion • Heat capacity
Properties of Water • Solutions and Suspensions • Mixture – physically mixed but NOT chemically combined • Solution – mixture where things are evenly distributed • Solute – substance that is dissolved • Solvent – substance in which solute dissolves • Suspensions – mixture of water and nondissolved material
Properties of Water • Acids, Bases and pH • pH scale – measures concentration of H+ (hydrogen ion) in solution • Ranges from 0 to 14 • 7 – neutral • Lower values – acidic • High values – basic • Buffers – weak acids or bases that prevent sharp, sudden changes
Carbon Compounds • The Chemistry of Carbon • Carbon atoms have 4 valence electrons (outermost – needed for reactions) • Allows them to bond with many different elements • Allows it to bond to itself to create long chains
Carbon Compounds • Macromolecules • Large molecules • Created when monomers (single units) form polymers (multi-units) • Four major types
Carbon Compounds • Carbohydrates • Made of carbon, hydrogen and oxygen • Main source of energy for living things • Can be used for structural purposes • Simple sugars – monosaccharides (glucose) • Complex – polysaccharides (glycogen and cellulose
Carbon Compounds • Lipids • Mostly carbon and hydrogen • Used to store energy • Important in membranes and waterproof coverings • Referred to as saturated (solid) and unsaturated (liquid)
Carbon Compounds • Nucleic acids • Made of hydrogen, oxygen, nitrogen, carbon and phosphorus • Store and transmit hereditary or genetic information • Nucleotides – monomers • Two kinds – RNA and DNA
Carbon Compounds • Proteins • Made of nitrogen, carbon, hydrogen, and oxygen • Control the rates of reactions and regulates cell process • Also used for structure and transport • Amino acids – monomer
Chemical Reactions and Enzymes • Chemical Reactions • A process that changes or transforms, one set of chemicals into another • Changes in chemical bonds • Reactants – what is put into the reaction • Products – what is gotten out of the reaction
Chemical Reactions and Enzymes • Energy in Reactions • Either released or absorbed when bonds are formed or broken • Energy sources – examples • Plants – sunlight • Animals – consumption (eating) and digesting • Activation energy – energy needed to get a reaction started
Chemical Reactions and Enzymes • Enzymes • Specialized proteins • Biological catalyst – speeds up the rate of a chemical reaction • Lower activation energy • Very specific – one enzyme one chemical reaction • Substrates – the reactants of an enzyme catalyzed reaction • Bind at active site (lock and key) • Affected by things such as temperature or pH