enzymes

• What are enzymes primarily responsible for in living organisms?

  They catalyze chemical reactions
• Why do living things need enzymes?

  To control thousands of chemical reactions
• What is the role of enzymes in chemical reactions?

  They speed up reactions without being used up
• What are enzymes made of?

  Chains of amino acids
• How do the shapes of enzymes relate to their function?

  Unique shapes allow them to catalyse reactions
• What is the active site of an enzyme?

  The region where substrates bind
• Why are enzymes considered picky?

  They usually catalyse only one specific reaction
• What happens if the substrate does not fit the enzyme's active site?

  The reaction won't be catalysed
• What is the 'lock and key' model of enzyme action?

  It describes how substrates fit into enzymes
• What is the 'induced fit' model of enzyme action?

  The active site changes shape for a tighter fit
• What effect does temperature have on enzyme activity?

  It changes the rate of enzyme-catalysed reactions
• What happens to enzymes at high temperatures?

  They can become denatured and lose function
• What is the optimum temperature for most human enzymes?

  Around normal body temperature
• How does pH affect enzyme activity?

  It can denature enzymes if too high or low
• What is the optimum pH for most enzymes?

  Often neutral pH 7
• What is unique about pepsin's optimum pH?

  It works best at pH 1.2 in the stomach
• How do stomach enzymes differ from small intestine enzymes?

  Stomach enzymes work best at low pH
• How do temperature and pH affect enzyme activity?

  Both can denature enzymes and affect function