chap 2 micro

• Chemistry


  The science of the interactions between atoms and molecules
• Atom


  The smallest unit of matter that can enter into a chemical reaction
• Molecules


  A combination of atoms forming a specific chemical compound
• Electrons


  A negatively charged particle in motion around the nucleus of an atom
• Protons


  A positively charged particle in the nucleus of an atom
• Neutrons


  An uncharged particle in the nucleus of an atom
• Electron shells


  A region of an atom where electrons orbit the nucleus, corresponding to an energy level
• Chemical element


  A fundamental substance composed of atoms that have the same atomic number and behave the same way chemically
• Isotopes


  A form of a chemical element in which the number of neutrons in the nucleus is different from the other forms of that element
• Electronic configuration


  The arrangement of electrons in shells or energy levels in an atom
• Valence


  The combining capacity of an atom or a molecule
• Chemical bonds


  An attractive force between atoms forming a molecule
• Covalent bonds


  A chemical bond in which the electrons of one atom are shared with another atom
• Hydrogen bonds


  A bond between a hydrogen atom covalently bonded to oxygen or nitrogen and another covalently bonded oxygen or nitrogen atom
• Chemical reactions


  The process of making or breaking bonds between atoms
• Chemical energy


  The energy of a chemical reaction
• Endergonic reaction


  A chemical reaction that requires energy
• Exergonic reaction


  A chemical reaction that releases energy
• Anabolism


  All synthesis reactions in a living organism; the building of complex organic molecules from simpler ones
• Catabolism


  All decomposition reactions in a living organism; the breakdown of complex organic compounds into simpler ones
• Exchange reactions


  A chemical reaction that has both synthesis and decomposition components
• Reversible reactions


  A chemical reaction in which the end-products can readily revert to the original molecules
• Organic compounds


  A molecule that contains carbon and hydrogen
• Inorganic compounds


  A small molecule that does not contain carbon and hydrogen
• Elements of life


  • H
  • C
  • N
  • O
  • S
  • M
  • P
• Acids


  A substance that dissociates into one or more hydrogen ions (H•) and one or more negative ions
• Bases


  A substance that dissociates into one or more hydroxide ions (OH‚) and one or more positive ions
• Salts


  A substance that dissolves in water to cations and anions, neither of which is H•or OH
• pH


  The symbol for hydrogen ion (H1) concentration; a measure of the relative acidity or alkalinity of a solution
• Carbon skeleton


  The basic chain or ring of carbon atoms in a molecule
• Function groups

  An arrangement of atoms in an organic molecule that is responsible for most of the chemical properties of that molecule
• Macromolecules


  A large organic molecule
• Monomers


  A small molecule that collectively combines to form polymers
• Dehydration synthesis


  Condensation reaction
• Condensation reactions


  A chemical reaction in which a molecule of water is released; also called dehydration synthesis
• 4 major classes of biomolecules

  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic acids
• Carbohydrates


  An organic compound composed of carbon, hydrogen, and oxygen, with the hydrogen and oxygen present in a 2:1 ratio; carbohydrates include starches, sugars, and cellulose
• Lipids (fats/oils)


  A non-water soluble organic molecule, including triglycerides, phospholipids, and steroids
• Proteins


  A large molecule containing carbon, hydrogen, oxygen, and nitrogen (and sulfur); some proteins have a helical structure and others are pleated sheets
• Nucleic acids


  A macromolecule consisting of nucleotides; DNA and RNA are nucleic acids