Carbs, Lipids, Proteins

• Explain how a change in the primary structure of a globular protein may result in a different tertiary structure:

  The primary structure is the sequence of amino acids in a polypeptide chain.

  If the sequence of amino acids in the primary structure changes, this will result in a different tertiary structure because the order of the amino acids are determine the location of hydrogen, ionic and disulphide bonds.

  Because the location changes, this causes the structure to fold in a different way changing its shape and its function
• Describe a biochemical test to find out if substance D is a non reducing sugar:

  -conduct Benedict’s test on sample to ensure no reducing sugars are present

  -add sample (solution) into a test tube and add an acid and boil it so it hydrolyses the bonds

  -then add an alkali to neutralise the acid

  -then use Benedict reagent by adding a few drops and heat it

  -if the result is positive the it should turn from clear blue to green,yellow, orange and brick red depending on the of non reducing sugars present
• How many molecules are formed when a triglyceride is hydrolysed?

  4 molecules (1 glycerol, 3 fatty acids)
• Describe two differences between a saturated and an unsaturated fatty acid:

  a saturated fatty acid has no carbon carbon double bonds whereas an unsaturated fatty acid has at least one carbon carbon double bond

  a saturated fatty acid has a maximum of hydrogen atoms
• GOS are polymers of galactose

  Explain why GOS are described as polysaccharides:


  Galactose is a type of monosaccharide. GOS is described as a polysaccharide as it’s a carbohydrate polymer. The repeating galactose molecules are held together by glycosidic bonds joined by a condensation reaction