8.2b Enzymes (Effect on temperature)

• Explain how temperature affects enzymes.

  • If its too cold - the enzymes work slow
  • Optimum (37°C) - the enzymes work best
  • Too hot - the enzymes denature (it loses its structure) and stops working
• Explain the amylase and starch experiment

  The experiment demonstrates how amylase breaks down starch into simpler sugars. Starch turns blue-black with iodine, but when amylase is added, it breaks down into sugars that don't react with iodine, causing a colour change. This reflects digestion, where amylase helps break down starchy foods for absorption.
• What is the independent variable in the amylase and starch experiment?

  The amylase enzyme
• What is the dependent variable in the amylase and starch experiment?

  the change in colour of the starch solution
• What variables should be controlled in the starch and amylase experiment?

  1. Temperature: should be kept constant throughout the experiment.
  2. pH: should be controlled and maintained at a constant level
  3. Time: the duration of the reaction should be controlled and standardised to allow for fair comparisons.
  4. Volume of solutions: The volumes of starch, amylase, and iodine solutions added should be carefully measured.
• Describe the results observed in the amylase and starch experiment.

  The control tube only containing starch remains blue-black when iodine is added indicating the presence of starch. In contrast, the experimental tube containing both starch and amylase may show a lighter colour or become colourless suggesting the breakdown of starch into simpler sugars by amylase.
• Explain why temperature affects enzymes.

  Temperature affects enzymes because it changes their shape. At low temperatures, enzyme activity is slow because molecules move slowly. In the optimal temperature range, enzyme activity increases. However, high temperatures can denature enzymes, causing them to lose function.