Starch and Amylase Experiment

Overview

• Purpose: To review the starch and amylase experiment using salivary amylase to break down starch into glucose.

Key Concepts

• Enzyme Used: Salivary amylase (from our saliva).
• Substrate: Starch (found in potatoes, rice, pasta).
• Product: Simple sugars (monomers), specifically glucose.
• Testing for Starch:
  • Chemical Used: Iodine.
  • Initial Color of Iodine: Orange-yellow (commonly referred to as yellow).
  • Positive Test for Starch: Blue-black color indicates the presence of starch.

Molecular Structure

• Starch:
  • Type of carbohydrate.
  • Known as a polymer (long chain of molecules).
• Amylase: Enzyme that breaks down starch into smaller glucose molecules (monomers).
• Active Site: Amylase fits perfectly with the starch substrate.

Experimental Setup

• Water Bath:
  • Used to maintain temperature during the experiment.
  • Two boiling tubes: one with amylase (saliva), the other with starch solution.
  • Keep both tubes at the same temperature (important for controlling variables).
• Temperature Control:
  • Affects enzyme activity and rate of reaction.

Procedure

1. Place iodine drops into the dimples of a spotting tile (initial color is yellow).
2. After 15 minutes in the water bath, mix the starch and amylase solutions.
3. Every few minutes, take a drop from the mixture and add it to iodine on the spotting tile to observe color change.

Observations and Results

• Initial drop color (time=0): Blue (indicating presence of starch).
• Subsequent drops every 2 minutes: Record color changes.
• Completion of Digestion:
  • Determined to be between 12 and 14 minutes.
  • Explanation: Color change from blue to yellow indicates all starch is digested.

Conclusion

• The experiment demonstrated how amylase breaks down starch and how iodine can be used effectively to track this process.
• Notable results observed by year 9 students during the experiment.