unit 1

• Polymer

  Substances made of repeating monomers
• Monomer of polypeptides

  Amino acids
• Common monosaccharides

  • Glucose
  • Fructose
  • Galactose
• Monomer that glycogen is made from

  Alpha glucose
• Monomer that starch is made from

  Alpha glucose
• Monomer that cellulose is made from

  Beta glucose
• Test for reducing sugars

  Heat with Benedict's, red precipitate if positive
• Test for non-reducing sugars

  Negative test from reducing sugar test, boil with acids neutralise with alkaline then heat with Benedict's and brick red if positive
• Test for starch

  Iodine , blue-black colour if positive
• Test for lipids

  Dissolve in ethanol, then add water and shake, white emulsion if positive
• Triglycerides

  Made from glycerol and 3 fatty acids
• Difference between phospholipid and triglyceride

  2 fatty acids and a phosphate group, hydrophobic and hydrophilic regions, forms bilayer
• Primary structure of a protein

  Number and order of amino acids (sequence)
• Quaternary structure

  Two or more polypeptides joined together
• Bonds involved in maintaining tertiary structure of proteins

  • Ionic
  • Hydrogen
  • Disulphide
• Test for proteins

  Biuret test - positive is purple
• Active site in induced fit model

  Active site not complementary to substrate, after substrate binds it causes a change in the tertiary structure of the active site to become complementary
• Active site in lock and key model


  Active site is exactly complementary in shape to the substrate
• Factors affecting enzyme-controlled reactions

  • Temperature
  • Substrate concentration
  • Enzyme concentration
  • Presence of competitors
  • pH
• Extracellular enzyme


  Enzymes that exist outside of cells
• Enzyme-substrate complex

  What enzymes form when they react with a substrate
• How enzymes work

  Lower the activation energy by putting strain on substrate bonds
• Why enzymes are specific

  Specific tertiary structure/shape of active site for one type of substrate
• Function of DNA

  Holds/stores genetic information
• Components of ribosomes

  • rRNA
  • Proteins
• Components of a nucleotide

  • Nitrogenous base
  • Pentose sugar
  • Phosphate group
• Bases in DNA

  • Adenine
  • Thymine
  • Cytosine
  • Guanine
• Complementary base pair rules

  1. T via 2 hydrogen bonds, G-C via 3 hydrogen bonds
• Bond formed in condensation reaction between 2 nucleotides

  Phosphodiester bond
• Bases in RNA

  • Adenine
  • Uracil
  • Cytosine
  • Guanine
• Role of DNA helicase

  Breaks the hydrogen bonds between complementary base pairs of the two strands in the double helix
• Role of DNA polymerase

  Catalyses the condensation reactions between adjacent nucleotides forming phosphodiester bonds
• Enzyme that hydrolyses ATP

  ATP hydrolase
• Products of ATP breakdown

  ADP and inorganic phosphate, releasing energy
• Effect of phosphorylation on compounds

  Become more reactive
• Components of ATP

  Adenine, 3 phosphates and a ribose sugar
• Enzyme that catalyses ATP synthesis

  ATP synthase
• Processes that can produce ATP

  • Respiration (aerobic and anaerobic)
  • Some in photosynthesis
• Important properties of water

  • Good solvent
  • Metabolite in condensation/hydrolysis reactions
  • High specific heat capacity and latent heat of vaporisation
  • Surface tension and cohesion between molecules due to hydrogen bonds
  • Ice less dense than liquid water
• Roles of sodium ions

  • Co-transport
  • Action potentials in nervous coordination