Biological molecules

• What are biological molecules?

  Molecules found in living organisms, such as carbohydrates, proteins, and lipids
• What are biological molecules generally made up of?

  Smaller units
• How can biological molecules be utilized in respiration?

  They can be broken down to fuel respiration and transfer energy to ATP
• What are the basic units that make up carbohydrates?

  Simple sugars
• What elements do carbohydrate molecules contain?

  Carbon, hydrogen, and oxygen
• What are the smallest units of carbohydrates called?

  Monomers
• What can simple sugars form when joined together?

  Long chains called polymers
• Name two examples of large complex carbohydrates.

  Starch and glycogen
• What happens to polymer molecules in the body?

  They can be broken down back into monomers
• How are carbohydrates digested in the body?

  By enzymes in the mouth and small intestine
• What are proteins made up of?

  Long chains of amino acids
• What elements do amino acids contain?

  Carbon, nitrogen, hydrogen, and oxygen
• How are proteins broken down in the body?

  By enzymes in the stomach and small intestine
• What are lipids made from?

  Glycerol and three fatty acids
• Why are lipids not considered polymers?

  They don’t form a long chain of repeating units
• What elements do lipids contain?

  Carbon, hydrogen, and oxygen
• How are lipids broken down in the body?

  By enzymes in the small intestine
• What is the importance of breaking down large, complex molecules like starch in the body?

  • Provides energy for cellular processes
  • Allows for the absorption of nutrients
• What is the test for reducing sugars?

  Add Benedict’s reagent and heat the sample
• What indicates a positive test for reducing sugars using Benedict’s reagent?

  A coloured precipitate forms in the solution
• What color change occurs with increasing concentration of reducing sugars in the Benedict’s test?

  Blue → green → yellow → orange → brick red
• How do you test for non-reducing sugars?

  Boil with a reducing sugar and then add Benedict’s reagent
• What color change indicates the presence of starch when tested with iodine?

  Changes from brown/orange to dark bluish-black
• What is the emulsion test used for?

  To test for lipids
• What indicates the presence of lipids in the emulsion test?

  A milky emulsion forms
• What is the Biuret test used for?

  To test for proteins
• What color change indicates the presence of protein in the Biuret test?

  The solution turns purple
• What is the first step in the Biuret test?

  Add sodium hydroxide solution to make the solution alkaline
• What conclusion can be drawn if a solution turns purple after adding sodium hydroxide and copper(II) sulfate?

  The solution contains protein