Biology Topic 1

• Monomer

  Smaller units which can create larger molecules
• Polymer

  Made from lots of monomers bonded together
• Types of carbohydrates

  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides to know

  • Glucose
  • Fructose
  • Galactose
• Glucose

  Key monosaccharide, molecular formula C6H12O6, can be drawn as a hexagon with 5 carbons in the ring and 1 carbon off the ring
• Isomers

  Molecules with the same molecular formula but different structures
• Alpha and beta glucose


  Differ in the orientation of the hydroxyl group on carbon 1
• Monosaccharides are the monomers of carbohydrates
• Disaccharides are two monosaccharides bonded together
• Polysaccharides are many monosaccharides bonded together
• The three monosaccharides to know are glucose, fructose and galactose
• Glucose is the key monosaccharide that needs to be studied in detail
• Disaccharide

  Two monosaccharides bonded together
• Glycosidic bond

  The bond that holds two monosaccharides together to form a disaccharide
• Condensation reaction

  Joining two molecules together through the removal of water
• Three disaccharides

  • Maltose
  • Sucrose
  • Lactose
• Disaccharide formation

  Involves a condensation reaction that removes water
• Hydrolysis

  The reverse of condensation, splitting molecules apart through the addition of water
• Digestion


  Large insoluble molecules like starch are hydrolyzed into small soluble molecules like glucose
• Glycogenolysis/Glycogen lysis


  The splitting of glycogen back into glucose
• Enzymes

  Biological catalysts that catalyze hydrolysis reactions
• Polysaccharides

  Molecules created by condensation reactions of multiple glucose monomers
• Polysaccharides

  • Starch
  • Cellulose
  • Glycogen
• Starch

  • Found in plants
  • Insoluble store of glucose
• Cellulose

  • Found in plant cell walls
  • Provides structural strength
• Glycogen

  • Found in animals (muscle and liver cells)
  • Insoluble store of glucose
• Formation of amylose

  1. Condensation reactions

  2. 1-4 glycosidic bonds

  3. Unbranched chain that coils into a helix
• Formation of amylopectin

  1. Condensation reactions

  2. 1-4 and 1-6 glycosidic bonds

  3. Branched polymer
• Formation of cellulose

  1. Condensation reactions of beta-glucose

  2. 1-4 glycosidic bonds

  3. Long straight chains held by hydrogen bonds
• Formation of glycogen

  1. Condensation reactions of alpha-glucose

  2. 1-4 and 1-6 glycosidic bonds

  3. Highly branched polymer
• Starch structure (amylose and amylopectin)


  Allows it to be compacted for storage and have large surface area for enzymes
• Insoluble nature of polysaccharides

  Prevents affecting water potential and osmosis
• Cellulose structure (long straight chains held by hydrogen bonds)


  Provides structural strength to plant cell walls
• Glycogen structure (highly branched)


  Allows rapid hydrolysis to release glucose for energy in animals
• Polysaccharides are formed from glucose monomers
• Starch and glycogen are storage polysaccharides, cellulose provides structural strength
• Triglycerides

  Lipid containing a glycerol molecule and three fatty acid chains
• Phospholipids

  Lipid containing a glycerol molecule and two fatty acid chains, with a phosphate group replacing the third chain
• Formation of triglycerides

  1. Glycerol bonded with three fatty acids through three separate condensation reactions

  2. Three water molecules removed

  3. Three ester bonds formed
• Fatty acid chains

  Can be saturated (all single bonds) or unsaturated (at least one double bond)