Lock and Key Model & Digestive Enzymes
The lock and key model explains enzyme action brilliantly. Think of the enzyme as a lock and the substrate as the key - they must fit together perfectly. The substrate binds to the enzyme, gets broken down into products, then the products are released, leaving the enzyme free for the next reaction.
Digestive enzymes are produced by specialised cells in your glands and gut lining. These enzymes flow into your digestive system where they encounter food molecules and break them down from large, insoluble chunks into tiny, soluble pieces your blood can absorb.
The three main types you need to know are protease (breaks down proteins), lipase (tackles fats and oils), and carbohydrase (handles carbohydrates). Without these molecular workers, you simply couldn't extract nutrients from your food.
Remember: Each enzyme type is highly specific - protease won't work on fats, and lipase can't break down proteins!