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Difficulty: EasyAnimal Nutrition and Digestive System

A sample of salivary amylase was kept in an ice bath at 0∘C0^\circ\text{C} for two hours and then mixed with a starch solution maintained at body temperature (37∘C37^\circ\text{C}). Which of the following best describes the outcome of this reaction?

  1. Starch is hydrolyzed to maltose because low temperature causes temporary inactivation rather than denaturation.Answer
  2. B
    Starch remains completely unhydrolyzed because low temperature permanently denatures salivary amylase.
  3. C
    Salivary amylase becomes permanently destroyed, preventing enzyme-substrate complex formation even after warming.
  4. D
    Starch is digested by saprophytic breakdown into glucose prior to enzyme warming.

Answer

Starch is hydrolyzed to maltose because low temperature causes temporary inactivation rather than denaturation.
Low temperatures render enzymes temporarily inactive due to reduced molecular collisions. When returned to an optimal temperature of 37∘C37^\circ\text{C}, salivary amylase regains catalytic activity and hydrolyzes starch into maltose.

Step-by-Step Solution

1
Analyze the effect of low temperature (0∘C0^\circ\text{C}) on enzyme structure and kinetic energy.
At 0∘C0^\circ\text{C}, salivary amylase molecules have very low kinetic energy, resulting in temporary inactivation without altering the active site shape.
Low temperature does not break the chemical bonds maintaining the enzyme's 3D structure.
2
Determine what happens when the enzyme is warmed to 37∘C37^\circ\text{C}.
The enzyme regains kinetic energy and normal catalytic activity at its optimum temperature of 37∘C37^\circ\text{C}.
Because the enzyme was not denatured, active sites can successfully bind starch substrates.
3
Identify the end product of starch breakdown by salivary amylase.
Salivary amylase breaks starch down into the disaccharide maltose.
Amylase specifically cleaves alpha-1,4-glycosidic bonds in starch.

Key Concept

Effect of Temperature on Digestive Enzymes
Estimated Time:45s
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Topics

Animal Nutrition and Digestive System

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