Biology paper 1

• Monomers are smaller units which can create larger molecules and the polymers are made from lots of monomers which are bonded together
• Monomers


  • glucose
  • amino acids
  • nucleotides
• Polymers


  • starch
  • cellulose
  • glycogen
  • proteins
  • DNA
  • RNA
• Condensation reaction to create polymers


  1. Joining two molecules together

  2. Creating a chemical bond

  3. Removing water
• Hydrolysis reaction to break apart monomers

  1. Breaking a chemical bond between two molecules

  2. Involving the use of water
• Carbohydrate monosaccharides


  • glucose
  • fructose
  • galactose
• Carbohydrate disaccharides


  • sucrose
  • maltose
  • lactose
• Carbohydrate polysaccharides


  • starch
  • cellulose
  • glycogen
• Alpha glucose


  Hydrogen atom on top, hydroxyl group on bottom of carbon 1
• Beta glucose


  Hydroxyl group on top, hydrogen atom on bottom of carbon 1
• Glycosidic bond


  Chemical bond that forms between two monosaccharides in disaccharides and polysaccharides
• Starch


  • Glucose store in plants
  • Alpha glucose monomers
• Cellulose


  • Structural strength in plant cell walls
  • Beta glucose monomers
  • One-to-four glycosidic bonds
• Triglycerides


  • High ratio of energy-storing carbon-hydrogen bonds
  • Can act as metabolic water source
  • Do not affect water potential
• Phospholipids


  • Hydrophilic head, hydrophobic tails
  • Form a bilayer in water
• Amino acid


  Central carbon, hydrogen, amine group, carboxyl group, variable R group
• Forming a dipeptide


  Condensation reaction removing water to create a peptide bond
• Forming a polypeptide


  Multiple condensation reactions joining amino acids by peptide bonds
• Primary protein structure


  Order or sequence of amino acids in a polypeptide chain
• Secondary protein structure


  Folding or twisting of the polypeptide chain, held by hydrogen bonds
• Tertiary protein structure


  Further folding of the polypeptide chain, held by ionic, hydrogen and disulfide bonds
• Quaternary protein structure


  Multiple polypeptide chains joined together
• Enzymes


  • Proteins in tertiary structure
  • Catalyze reactions by lowering activation energy
  • Have a specific active site complementary to one substrate
• Induced fit model


  Enzyme active site slightly changes shape to mold around the substrate
• Factors affecting enzyme-controlled reaction rate

  • Temperature
  • pH
  • Substrate concentration
  • Enzyme concentration
  • Inhibitors
• Effect of temperature on enzyme rate

  • Lower temperature = less kinetic energy, fewer successful collisions

  Higher temperature = bonds break, enzyme denatures
• Effect of pH on enzyme rate

  • Extreme pH values cause enzyme denaturation
• Effect of substrate concentration on enzyme rate

  • Increasing substrate increases rate until active sites saturated
• Effect of enzyme concentration on enzyme rate

  • Increasing enzyme increases rate until substrate saturated
• Competitive inhibitor


  Binds to the enzyme's active site
• Non-competitive inhibitor


  Binds to a different part of the enzyme
• Competitive inhibitor


  Binds to the active site of an enzyme, preventing the substrate from binding
• Non-competitive inhibitor


  Binds to the allosteric site of an enzyme, changing the shape of the active site and preventing the substrate from binding
• Biochemical test for starch

  1. Add iodine

  2. Positive test result: iodine goes from orangey brown to blue black
• Biochemical test for reducing sugars

  1. Add Benedict's reagent

  2. Heat
• Biochemical test for non-reducing sugars


  1. Do Benedict's test for reducing sugars

  2. If negative, add acid and boil

  3. Cool and neutralise

  4. Add Benedict's reagent again

  5. Positive test result: solution turns orange or brick red
• Biochemical test for proteins

  1. Add biuret reagent

  2. Positive test result: solution turns purple
• Biochemical test for lipids

  1. Dissolve sample in ethanol and shake

  2. Add distilled water

  3. Positive test result: white emulsion forms
• DNA


  Contains the genetic code and can be passed on to make new cells and to the next generation
• DNA


  • Polymer of nucleotides
  • Two polymer chains join to form a double helix