Sugars 🍰

• What is a monomer?

  A small repeating unit that forms polymers.
• What is the chemical process that is involved in the linkage of two monomers?

  Condensation reaction
• Name the monomers from which a maltose molecule is made ?

  A glucose + A glucose
• name the type of chemical bond that joins two monomers together.

  Glycosidic bond
• What are the monomers that make up a maltose molecule?

  Two glucose molecules
• What type of bond joins the monomers in maltose?

  Glycosidic bond
• What is concentration measured in?

  mol/dm^3
• explain how you would use a graph to determine maltose concentration with a light absorbsance of 0.45 arbitrary units


  Draw a line of best fit then read the x axis at 0.45
• The formula for galactose is c6h12o6

  What is the formula for lactose ?

  Keep in mind

  Lactose + water ➡️ with lactase = glucose + galactose

  Add glucose and galactose

  C6H12o6 + c6h12o6

  = c12h24o12

  Take water (h2o) off to get lactose

  C12H24O12 - H2O

  = C12H22O11
• Describe the chemical test to carry Out which shows that Lactose is a reducing sugar.

  Put benedicts into the solution and heat gently

  colour change of red shows positive for being a reducing sugar
• A chemical test was carried out on samples A and B both tubes left for precipitate to settle

  1. lactose and water (A)
  2. galactose and glucose (B) So is galactose a reducing sugar?

  Yes as it shows more precipitate in sample B where both glucose and galactose are reducing sugars.
• 3 types of carbohydrates

  Fibres, sugars, starch
• Name 3 disaccharides


  Galactose , glucose ➡️ lactose

  glucose, fructose ➡️sucrose

  a glucose x 2 ➡️ maltose
• Between 2 disaccharides is..

  A glycosidic bond
• What is the difference between alpha and beta glucose?

  The position of the hydroxl group (OH)
• If you test a solution contain8jg both glucose and sucrose you cannot show the prescience of sucrose by carrying out a non reducing sugar test, explain why?

  Sucrose must be broken down into a monosaccharide
• The test for starch using iodine causes a blue black colour to form this happens because the iodine forms an ion that sticks inside the amylose starch helix.

  If the starch iodide complex is boiled the blue black colour disappears why?

  Because the compound of iodine and starch is unstable
• Define a polymer


  A large repeating unit made up of monomers in a chain
• Bond formed..

  Glycosidic bond
• Describe how the student should carry out the test investigating the minimum concentration of glucose solution needed to produce a positive benedicts result.


  Add Benedict’s to the sample of glucose

  Bring solution to a boil and see if a coloured precipitate has formed

  If not add another 1 mol and see if colour change occurs.

  Green, yellow or red for a positive result!