Paper 1 biology

• What factors affect the functioning of enzymes and the rate of enzyme-controlled reactions?

  Temperature and pH
• How does temperature affect the rate of an enzyme-controlled reaction?

  As temperature increases, the rate of reaction increases until a certain point.
• At what temperature does the rate of enzyme-controlled reactions start to drop rapidly?

  About 37 degrees Celsius
• Why does the rate of reaction drop after reaching a certain temperature?

  High temperatures break some of the bonds holding the enzymes together, changing the active site's shape.
• What happens to an enzyme when it is denatured?

  It can no longer bind to the substrate and catalyze the reaction.
• At what temperature does the enzyme become denatured in this context?

  Around 45 degrees Celsius
• What is the optimum temperature for enzyme activity mentioned in the video?

  37 degrees Celsius
• Do different enzymes have the same optimal temperature?

  No, different enzymes have different optimal temperatures.
• What does pH measure?

  Acidity
• How does pH affect the rate of enzyme-controlled reactions?

  If the pH is too high or too low, it lowers the rate of reaction.
• What happens to the active site of an enzyme when the pH changes significantly?

  The active site changes shape, which can prevent the substrate from fitting.
• What is the term for the pH at which an enzyme works best?

  Optimal pH
• What is the optimal pH for most enzymes in the human body?

  Around 7 (neutral pH)
• What is the optimal pH for enzymes that work in the stomach?

  Around 2
• What are the effects of temperature and pH on enzyme activity?

  • Temperature increases reaction rate until denaturation occurs (around 45°C).
  • Optimal temperature for most enzymes is around 37°C.
  • pH affects reaction rate; extreme pH levels can lead to denaturation.
  • Optimal pH for most enzymes is around 7; stomach enzymes work best at pH 2.
• What resources are available for further learning on this topic?

  • Learning platform with videos and practice questions.
  • Links to lessons and playlists for organized study.