Enzymes

• Enzymes are proteins that act as biological catalysts, speeding up metabolic reactions
• Enzymes are specific with a unique active site that allows them to bind to their substrate due to complementary shapes (the 'lock and key' theory)
• Above the optimum temperature, bonds in the enzyme start to break, causing denaturation where the active site changes shape and can't bind to the substrate anymore
• Enzymes become denatured above and below the optimum pH
• Cells are the basic building blocks of all living organisms
• A tissue is a group of cells with a similar structure and function
• Organs are groups of different tissues performing specific functions
• Organ systems are a group of organs working together to perform a particular function
• Digestion is the breakdown of large, insoluble molecules into small, soluble molecules for absorption into the bloodstream
• Chemical digestion involves enzymes breaking down food:

  • Carbohydrases convert carbohydrates into simple sugars (e.g., glucose)
  • Proteases break down proteins into amino acids
  • Lipases break down lipids into glycerol and fatty acids
• Hydrochloric acid in the stomach:

  • Kills bacteria
  • Provides the optimum pH for the enzyme protease to work
• Bile, produced in the liver and stored in the gall bladder, is alkaline and neutralizes stomach acid to create an alkaline environment for small intestine enzymes to work best