WB3 - Biological Molecules

• Starch is tested by using an iodine solution. When positive for starch, it is blue/black. When negative for starch, it is red/brown in colour. It is digested through amylase. Its monomer is glucose.
• Reducing sugars are tested by using a Benedict solution. When positive for reducing sugars, it is green/brown. When negative for reducing sugars, it is blue in colour. It is digested through amylase. Its monomer is glucose.
• Proteins are tested by using a Biuret solution. When positive for protein, it is purple. When negative for protein, it is blue in colour. It is digested through protease. Its monomer is amino acids.
• Fat/oils are tested by using an Ethanol solution. When positive for fats/oils, it is cloudy. When negative for fats/oils, it is colourless. It is digested through lipase. Its monomer is glycerol and fatty acids.
• Two examples of sugar (which is a type of carbohydrate) are glucose and sucrose.

  
  

  (Role in living organisms)

  Glucose provides energy which is released by respiration; also the form in which carbohydrates are transported in mammalian blood.

  
  

  Sucrose is the form in which carbohydrates are transported in plants.
• Two examples of polysaccharide (type of carbohydrate) are starch and glycogen.

  
  

  (Role in living organisms)

  Starch is the form in which plants store energy.

  
  

  Glycogen is the form in which animals store energy.
• Glycogen is the form in which animals store energy
• Starch is the form in which plants store energy