Enzymes

• What are enzymes?

  Enzymes are biological catalysts that speed up the rate of the reaction without being USED UP.
• Enzymes are made of..?

  proteins that are made out of amino acids
• What are the two enzyme models?

  • Lock and key model
  • Induced fit model
• What is the lock and key model?

  Enzymes are specific to the substrate they bind too, and after a product is formed, it is released as it doesnt fit the active site anymore
• What is the induced fit model?

  substrate enters an enzyme's active site and the enzyme alters its shape slightly so the substrate can fit
• One way to increase the rate of reaction is to increase the temperature.

  State reasons why we cannot always do this.

  • It can damage our cells
  • It can require a lot of energy
  • It can also speed up non-useful reactions
• Are enzymes specific?


  Yes, as they are made out of long chains of amino acids, and depending on what way they fold up, they create different enzymes
• How do enzymes work?

  -Can get a substrate and break it into multiple products

  -Or get multiple products back into a substrate
• What is the active site, and explain the role of it.

  the region on the enzyme where the substrate binds, and is complementary to the substrate

  
  

  The shape of the active site matches the shape of the substrate molecules and holds them together so bonds can form between them to make the product. The product molecule doesn't fit into the active site well so is released.
• What 3 factors affect enzyme activity?

  temperature, pH, substrate concentration
• How does temperature affect enzyme activity?

  • Low temps= Molecules move slow so substrates take longer to reach and bind with active sites
  • Optimum temps= The enzyme is working at its fastest rate
  • High temps= Cause the active site to change shape, so it cant hold the substrate as tightly and the reaction goes more slowly
  • At very high temps= The active site breaks up and the enzyme is denatured
• How does substrate concentration affect enzyme activity?

  -At low substrate concentration not every active site of each enzyme is busy so adding more substrate increases the rate of reaction

  -At high substrate concentration adding more substrate has little effect because the active site of every molecule is busy.
• What does the large molecule carbohydrates break down into?

  It is broken down into sugars with the enzyme AMYLASE
• What does the large molecule proteins break down into?

  It is broken down into amino acids with the enzyme PROTEASE
• What does the large molecule lipids break down into?

  It is broken down into fatty acids and glycerol with the enzyme LIPASE
• What is PH?


  measure of acidity
• Effects of pH on enzyme activity

  If pH is too low or too high it lowers the rate of reaction

  If PH is too high the enzyme gets denatured
• Explain how increasing the temperature can cause an enzyme to denature.

  -High temperatures start to break the bonds holding the enzyme together

  -This causes the enzyme and it's active site to change shape

  -This means the enzymes active site will no longer be complementary to the substrate