Chapter 2

  1. Matter; Difference between mass & weight
    • Matter - Anything that has mass and occupies space
    • Mass - how much matter an object has
    • Weight - measure of how strong gravity pulls on matter (mass=weight)
  2. Elements
    • The simplest chemical substances
    • 92 naturally occurring
    • 98% of body weight is made up of oxygen, carbon, hydrogen and nitrogen
    • Magnesium 0.06% - cofactor for many enzymes
    • Iron 0.007% - essential for oxygen transport and energy capture
  3. Atoms
    Smallest unit of matter that maintains all the properties of an element
  4. Subatomic particles
    • Protons - positive charge; found in atomic nucleus; mass of 1 Dalton
    • Neutrons - no charge; found in atomic nucleus; mass of 1 Dalton
    • Electrons - no charge; found in electron cloud - orbits nucleus; mass is 1/2000th of a Dalton (negligible)
  5. Mass Number
    • Defines mass of an atom
    • equal to number of protons + number of neutrons
    • approximation only (ignores electrons)
    • written as a superscript 23Na
  6. Atomic Mass (atomic weight)
    • Actual mass of the atom (including electrons)
    • Will be close to the mass number
    • Written below symbol on periodic table
    • This number can be rounded for mass number
  7. Atomic Number
    • Defines the element
    • Equal to the number of protons in the nucleus
    • assuming atom is neutral it is also equal to the number of electrons
    • written as a subscript 11Na
    • written above symbol on periodic table
  8. Isotopes
    • Different atomic forms of an element
    • Atoms with same atomic number can differ in # of neutrons
    • If an isotope is unstable (radioactive) nucelus decays and emits energy
  9. Half Life
    Amount of time for half of a given amount of an isotope to decay
  10. Subatomic Particles
    • Protons and neutrons in nucleus
    • Electrons orbit at fixed distances (eloectron cells)
    • Maximum in first shell 2 electrons, max in second and third 8 electrons
    • Atoms want outer (valence) shell filled
    • electrons in valence shell are valence electrons
    • Atoms with incomplete valence shells are reactive; atoms with complete valence shells are unreactive
  11. Chemical Bonds
    Attraction between two atoms caused by sharing or transferring of valence electrons
  12. Covalent Bonds
    Sharing of a pair of electrons between two atoms (forms a molecule)
  13. Electronegativity
    the attraction of a particular kind of atom for the electrons of a covalent bond (how stingy are the atoms)
  14. Nonpolar Covalent Bond
    • Generally occurs between atoms with the same electronegativity
    • Equal sharing of electrons
    • H-H one pair of electron shared - single covalent bond
    • O=O two pairs of electrons shared - double covalent bond
  15. Polar Covalent Bond
    • Occurs between atoms with different electronegativity
    • Unequal sharing of electrons
    • Water is a polar covalent bond; oxygen has greater electronegativity
  16. Ionic Bond
    • Transfer of electrons from one atom to another
    • Highly electronegative atom "strips" electron from another atom
    • Strength varies (depends on enviroment)
  17. Hydrogen Bond
    • Occurs between H atom of 1 polar covalent bond and N or O of another covalent bond
    • Weak bond
  18. Chemical Reactions; Reactant; Product
    • Making or breaking of chemical bonds that leads to chanes in composition of matter
    • Cannot create or destroy matter only rearrange atoms and bonds
    • Reactant - starting materials
    • Product - resulting materials
  19. Metabolism; Work; Energy (two types)
    • All the reactions in the cells/tissues of the body at a given moment
    • Work -movement of an object or change in physical structure of matter
    • Energy - capcity to perform work
    • Kinetic energy - energy of motion
    • Potential energy - stored energy
  20. Catabolic Reactions (decomposition); hydrolysis reaction
    • breaking down molecules
    • Catabolic reaction splits water and adds H and OH to products
  21. Anabolic reaction (synthesis); Dehydration Synthesis reaction
    • building up molecules
    • Dehydration synthesis (condensation) - anabolic reaction form water by removing H and OH from reactants
  22. Enzymes
    • Proteins that selectively speed up chemical reactions without being changed
    • Lower activatgion energy (the energy required to start a reaction)
  23. Exergonic
    Energy released (also called exothermic)
  24. Endergonic
    Energy absorbed (also called endothermic)
  25. Substrates
    Reactants in an enzymatic reaction
  26. Active Site
    • groove in an enzyme that binds one or more substrates (grooves made by tertiary protein structure)
    • Enzyme substrate complex - allowed for interaction of substrates and enzyme to take place
    • Specific for substrate (lock and key model)
    • Enzyme brings molecule together allowing synthesis/decomposition reactions
  27. Water
    • Supports life (cells are 70-90% water) and participates in some reactions
    • Dissolves organic/inorganic molecules
    • High heat capacity (absorbs/retains heat)
    • Effective lubercant in the body
  28. Solvent
    • Substance that does the dissolving
    • Water is the solvent of life
  29. Solute
    Substance that is dissolved
  30. Solution
    Solute + Solvent
  31. Aqueous Solution
    • When water is the solvent
    • Good solvent due to polarity
    • Water forms hydration sphere (shell) around ions that breaks down compound
  32. Electrolytes
    Compunds that dissociate in water and release ions
  33. Hydrophilic Substance
    Hydrophobic Substance
    • Hydrophilic - polar substance interacts with water
    • Hydrophobic - non-polar substance does not interact with water
  34. Acid
    Solute that dissociates in solution and releases free hydrogen ions (H+)
  35. Base
    • Solute that dissociates in solution and releases hydroxyl ions (OH-)
    • Binds to hydrogen ions to form water
  36. pH
    • Measures concentration of hydrogen ions
    • pH = -log[H+]
  37. Buffers
    • Compunds that stabilize the pH of a solution by removing or adding hydrogen ions
    • Maintain pH of body fluids within normal limits
  38. Carbonic Acid/Bicarbonate System
    • CO2 + H2O <-----------> H2CO3 <----------> HCO3- + H+
    • Carboxyl Acid Bicarbonate
  39. Blood pH range
    ranges from 7.35 - 7.45
  40. Acidosis/Alkalosis
    • Acidosis <7.35 produces coma
    • Alkalosis >7.45 produces sustained skeletal muscle contractions
Card Set
Chapter 2