GCSE Biology (AQA)

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Digestive Enzymes

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Organisation Animal Tissues, Organs and Organ Systems

Digestive Enzymes

2:10 Digestion
Spec 4.2.2.1
Previous The Human Digestive System Next Lock & Key Theory
  • Enzymes are proteins that catalyze reactions in the body.
  • Digestive enzymes break down foods into small, soluble molecules for absorption into the bloodstream.
  • When consuming food like an apple, digestive enzymes convert it into small food molecules in the digestive system.
  • These molecules are absorbed from the intestines into the bloodstream.
  • Enzymes act on molecules called substrates.
  • The part of the enzyme that interacts with the substrate is known as the active site.
  • Substrates bind to the enzyme's active site because their shapes are complementary.
  • Enzymes break down the bonds within substrates to produce new molecules called products.
  • After the reaction, products are released from the enzyme, allowing the enzyme to start the process again with new substrates.
  • The products of digestion are used to build new carbohydrates, lipids, and proteins.
  • Not all enzymes break down substances; some, known as synthesis enzymes, help build new substances, such as proteins from amino acids.
  • Understanding enzymes is crucial for relating to metabolism, which involves the digestion and synthesis of organic compounds like proteins, carbohydrates, and lipids.

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