Breakdown of Biological Molecules by Enzymes

Introduction

• Purpose: To understand how carbohydrates, proteins, and lipids are broken down by enzymes into smaller, absorbable molecules.
• Reason: Large molecules cannot be absorbed into the bloodstream across the villi of the small intestine without being broken down.

Enzymes

• Definition: Special proteins that speed up chemical reactions.

Carbohydrates

• Common Sources: Foods such as pasta and potatoes.
• Form: Primarily in the form of starch, a polymer of glucose.
• Breakdown Process:
  • Enzyme: Amylase
    • Breaks down starch into maltose (two glucose molecules linked together).
  • Enzyme: Maltase
    • Converts maltose into glucose, which is absorbable.
• Enzyme Naming: Enzymes often end in "-ase".

Proteins

• Common Sources: Meat and nuts.
• Breakdown Process:
  • Enzyme Group: Protease
    • Breaks proteins into amino acids.
    • Includes specific enzymes like trypsin and pepsin.

Lipids

• Common Sources: Fats and oils, e.g., avocados and olive oil.
• Breakdown Process:
  • Enzyme: Lipase
    • Breaks lipids into glycerol and fatty acids.
  • Role of Bile:
    • Not an enzyme but emulsifies lipids.
    • Breaks big lipid droplets into smaller ones to increase the surface area for enzyme action.

Production Sites of Enzymes

• Pancreas and Small Intestine: Produce all three types of enzymes (amylase, protease, lipase).
• Salivary Glands: Produce amylase.
• Stomach: Produces proteases.

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