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WAEC Biology 2007 Question 33

Question 33

Food Substances and Enzymes

Use the following equations to answer the question:
I – Boiled saliva + starch → X
II – Fresh saliva + starch → Y
What substances do X and Y represent?

  1. A.X = Maltose and Y = Sugar
  2. B.X = Starch and Y = Maltose
  3. C.X = Sugar and Y = Starch
  4. D.X = Maltose and Y = Starch
Show the answer and explanation

Answer: B (X = Starch and Y = Maltose)

Explanation

Boiling destroys the amylase in saliva, so the starch stays unchanged (X); fresh saliva digests starch to maltose (Y).