T2 chemistry

• Elements


  Atoms with same weight and same number of protons, neutrons and electrons
• Common elements in human body

  • Oxygen
  • Carbon
  • Hydrogen
  • Nitrogen
  • Calcium
  • Phosphate
• Atomic number


  Number of protons in the nucleus of the atom
• Model of an atom

  • Nucleus containing protons and neutrons surrounded by an electron cloud
  • Atoms must lose or gain electrons in order to retain structure (to be stable)
• Ions


  Atoms that have lost or gained electrons, so they are positively or negatively charged
• Ions in the body (electrolytes)

  • Sodium ions
  • Potassium ions
  • Calcium ions
  • Chloride ions
• Electrolytes


  Play roles in various body processes - nerve impulse conduction and muscle contractions
• Electrolytes must be present in body in specific amounts to maintain homeostasis
• Hydrogen, carbon, nitrogen, oxygen, calcium and phosphorus make up 99% of the body
• Solution


  Homogenous mixture of a solute in a solvent
• Solute


  Material present in smaller amount in solution
• Solvent


  Material present in larger amount in solution
• Diffusion


  Movement of molecules from an area of high solute concentration to low solute concentration to reach equilibrium or equalise solute concentration throughout the medium
• Factors affecting rate of diffusion

  • Difference in concentration
  • Temperature
  • Size of diffusing particles
  • Surface area for diffusion
  • Diffusion distance
• Osmosis


  Movement of water from a region of high water (solvent) concentration to a region of lower water concentration through a semi-permeable membrane
• pH scale


  0 to 14, and correlates negatively with the concentration of hydrogen ions
• Acids


  Ionic compounds that release hydrogen ions when immersed in water
• Bases/Alkaline


  Ionic compounds that accept hydrogen ion when immersed in water
• Water is neutral, pH of 7
• Substances with a pH less than 7

  Acids, have high H+ concentrations
• Substances with a pH greater than 7

  Bases, have lower H+ concentrations
• Acids


  • Taster sour (vinegar, lemon juice)
  • Can 'dissolve' many substances
  • Can 'burn'
• Alkaline or bases


  • 'opposite' of acids
  • Taste bitter
  • 'dissolve' many substances
• Outside acceptable level of pH, proteins will begin to denature, rendering them incapable of carrying out their many functions- acting as catalysts pr enzymes
• Buffer solution


  Composed of weak acid and conjugate base used to stabilise pH solution
• Bicarbonate buffering equation


  1. If there is a lot of CO2, the chemical equation goes to the right, and CO2 combines with water to form carbonic acid (H2CO3), which then dissociates into bicarbonate ions (HCO3-) and H+ ions

  2. If there are a lot of H+ ions, the blood is acidic. To restore equilibrium, the chemical equation goes to the left and bicarbonate "mops up" excess hydrogen ions and forms carbonic acid then CO2
• The lungs help regulate CO2 levels by increasing respiratory rate and excreting CO2
• Organic molecules


  Molecules that contain carbon
• Inorganic molecules


  Molecules with no carbon
• Macromolecules


  Organic biologic molecules that are very large
• Polymers


  Molecules that are made up from repeating building blocks called monomers
• 4 main macromolecules in human body

  • Carbohydrates (store and provide short-term energy)
  • Lipids (store fat and provide long-term energy)
  • Proteins (provide cell structure and contribute to chemical reactions)
  • Nucleic acids (store and provide genetic information)