1.1- Chemical elements and biological molecules

• organic


  molecules that have a high proportion of carbon atoms. 2 or more
• inorganic


  a molecule or ion that has no more than one carbon atom
• dipole


  a polar molecule, with a positive and negative charge, separated by a very small distance.
• hydrogen bond


  weak, attractive forces between a hydrogen atom with a parallel positive charge and an atom with a partial negative charge, usually o2 or N.
• monosaccharides


  an individual sugar molecule
• isomer


  molecules with the same molecular formula but different structural formulae.
• polymer


  a large molecule compromising of repeated units/ monomers, bonded together.
• ester bond


  an oxygen atom joining 2 atoms, one of which is a carbon atom attached by a double bond to another o2 atom.
• peptide bond


  chemical bond formed by a condensation reaction between the amino group of one amino acid and the carboxyl group of another.
• magnesium-mg2+

  • component for chlorophyll-plant
  • leaves become yellow without mg2+
  • mammals need magnesium for bones
• iron- fe2+


  Component of haemoglobin, which transports o2 in red blood cells
• phosphate- po4 3-

  • makes nucleotides, including atp
  • constituent of phospholipids, found in biological membranes.
• calcium- ca2+

  • strengthens bones and teeth in mammals
  • component of plant cell walls, providing strength
• water

  • dipole
  • H2- positive charge, O2- negative charge. NO overall charge.
  • polar molecule
  • charges are very small- delta +/- *
  • made up of 2 H2 atoms and one O2 atom covalently bonded together. Within the covalent bonds the electrons are not equally shared *
  • *= why water is a polar molecule
• what bonds form between the delta + on a H2 atom of one H2o molecule and the delta - on an O2 atom of another?

  • hydrogen bonds:
  • weak
  • large number present in water
  • molecule difficult to separate
• H2o diagram

  ////= hydrogen bonds

  -= covalent bonds

  A) delta negative-always

  B) delta + always

  C) h-bonds

  D) covalent bonds

  
• 8 properties of water

  • solvent- Due to water being a dipole, they attract charged particles like ions and glucose. These dissolve in water so chemical reactions take place in solution. Water acts as a transport medium eg in animals, plasma transports dissolved substances and in plants, water transports minerals in the xylem and sucrose and amino acids in the phloem. Non-polar molecules like lipids do not dissolve in water.
• Monosaccharide


  A single sugar molecule such as glucose or fructose, the simplest type of sugar.
• amino acids


  An organic molecule containing a carboxyl group and an amino group; serves as the monomer of proteins.
• Disaccharide


  A molecule composed of two monosaccharides. Common disaccharides include maltose, sucrose, and lactose.
• peptide bond


  The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a condensation reaction.
• dipeptide


  A combination of two amino acids joined by a peptide bond.
• Condensation reaction


  A chemical reaction in which two molecules become covalently bonded to each other through the loss of a water molecule.
• polypeptide


  A polymer (chain) of many amino acids linked together by peptide bonds.
• Glycosidic bond


  The bond between sugars.
• disulfide bond


  covalent S=S bond formed when the sulfur atoms amino acids (such as cysteine) in two adjacent protein chains are joined together.
• Hydrolysis


  water breaks chemical bonds
• Globular protein


  More 3-dimensional in shape and are mostly water soluble e.g. Haemoglobin
• Starch


  A polysaccharide storage molecule made by plants from glucose.
• Haemoglobin


  A quaternary globular protein with 4 polypeptide chains , each with a iron-containing heam group which binds to oxygen
• Isomer


  Compounds with the same molecular formula but different structures.
• Collagen


  A quaternary fibrous protein with a triple-helix that gives it strength. Tissues with a lot of collagen fibers are typically very strong, e.g. bone, tendons, ligaments
• Denaturation


  A process in which a protein unravels, losing its specific active site structure and hence function; can be caused by changes in pH or by high temperature.
• Glycogen


  An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.
• Tertiary structure


  Further folding of the secondary structure to form a 3D shape. Formed by interactions between amino acids R side chains forming hydrophobic interactions/ionic bonds/hydrogen bonds/disulfide bridges.
• Cellulose


  A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by β glycosidic linkages.
• Primary structure


  The sequence of amino acids in a protein
• Alpha Glucose

  
• Secondary structure


  Folding of the primary structure into alpha helices, beta pleated sheets and/or random coils
• Beta Glucose