Chap 3 Biological molecules

• Carbohydrates

  • Biological molecules that serve as nutrients that are essential for living organisms
  • Can be classified as: single sugars (monosaccharides), double sugars (Disaccharides), complex carbohydrates (polysaccharides)
• Single sugars

  • glucose
  • fructose
• Reducing sugars

  • Basic unit of carbohydrate
  • Small enough to pass through cell membranes
• Glucose and fructose are examples of reducing sugars
• Double sugars

  Formed when two single sugars are joined together
• Common double sugars

  • maltose (glucose + glucose)
  • sucrose (glucose + fructose)
• Benedict's Test

  1. Add 2 cm³ of Benedict's solution to 2 cm³ of food sample in a test-tube

  2. Shake the mixture

  3. Heat the contents in a boiling water bath for 2-3 minutes
• Benedict's Test

  • A green, yellow or red precipitate is formed if reducing sugar is present in trace, moderate or large amounts, respectively
• Glucose, fructose and maltose are examples of reducing sugars
• Water is an essential component of all body tissues
• Water

  • 70% of our body weight is water
  • Is a solvent in which chemical reactions take place
  • Is essential for photosynthesis (Carbon dioxide + water -> glucose + oxygen)
  • Keeps cells turgid or firm
  • Helps in the transport of mineral salts in plants
  • Regulates body temperature
  • Helps to transport dissolved substances around the body