3.1 Biological Molecules

• what are monomers?

  monomers are the smaller units from which larger molecules are made.
• what are polymers?

  polymers are molecules made from a large number of monomers joined together.
• what polymers are made from the monomer glucose?

  starch

  cellulose

  glycogen
• what polymers are made from the monomer amino acids?

  protein
• what polymers are made from the monomer nucleotide?

  DNA and RNA
• what polymers are made from the monomer monosaccharide?

  polysaccharide
• what is a condensation reaction?

  a condensation reaction joins two molecules together with the formation of a chemical bond and involves the elimination of a molecule of water.
• what is a hydrolysis reaction?

  a hydrolysis reaction breaks a chemical bond between two molecules and involves the use of a water molecule.
• examples of monosaccharides?

  glucose

  fructose

  galactose
• examples of disaccharides?

  sucrose

  maltose

  lactose
• examples of polysaccharides?

  starch

  cellulose

  glycogen
• what are the 2 isomers of glucose?

  a-glucose and b-glucose
• how are disaccharides formed?

  by the condensation reaction of two monosaccharides.
• what type of bond are disaccharides joined by?

  glycosidic bond
• what does glucose and glucose make?

  maltose and water
• what does glucose and galactose make?

  lactose and water
• what does glucose and fructose make?

  sucrose and water
• which glucose monomer is starch made up of?

  a-glucose
• which glucose monomer is glycogen made up of?

  a-glucose
• which glucose monomer is cellulose made up of?

  b-glucose
• what cell is starch found in?

  plant cells
• what cell is glycogen found in?

  animal cells
• what cell is cellulose found in?

  plant cells
• what are the two polymers that make up the structure of starch?

  amylose and amylopectin.
• what is the function of starch?

  has a helix shape so is compact to fit a lot of glucose in a small space.

  branched surface which increases surface area.

  insoluble so won't affect water potential.
• what is the structure of glycogen?

  it is a highly branched molecule.
• what is the function of glycogen?

  can be compacted easily.

  branched surface which increases surface area.

  insoluble so won't affect water potential.
• what is the structure of cellulose?


  forms long, straight unbranded chains held in parallel by many hydrogen bonds to form fibrils.
• what is the function of cellulose?

  has many hydrogen bonds which provide collective strength.

  gives plant walls strength and rigidity.

  insoluble so won't affect water potential.
• suggest how glycogen acts as a source of energy?

  • it is hydrolysed back to glucose.
  • glucose is used in respiration.
• explain the difference in structure of starch and cellulose

  • starch is formed from a-glucose whereas cellulose is formed from b-glucose.