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Zorluk: KolayAnimal Nutrition and Digestive System

A sample of human salivary amylase was boiled at 100∘C100^\circ\text{C} for ten minutes and then cooled to 37∘C37^\circ\text{C} before being added to a starch solution at optimal pH\text{pH}. After incubating for an hour, iodine testing revealed that starch was still present. Which of the following statements explains why starch digestion did not occur?

  1. The high temperature permanently altered the 3D structure of the enzyme active site, causing denaturation.Cevap
  2. B
    The enzyme became temporarily inactive due to high temperature and required freezing to restore its catalytic activity.
  3. C
    Boiling changed the mode of digestion from intracellular enzyme action to extracellular saprophytic nutrition.
  4. D
    The amylase molecules were converted into starch molecules by the extreme heat treatment.

Cevap

The high temperature permanently altered the 3D structure of the enzyme active site, causing denaturation.
Enzymes are protein molecules with precise three-dimensional active sites. Exposing salivary amylase to 100∘C100^\circ\text{C} causes heat denaturation, breaking bonds that maintain its tertiary structure. This structural collapse permanently destroys the active site, preventing starch binding even after the temperature returns to 37∘C37^\circ\text{C}.

Adım Adım Çözüm

1
Identify the nature of salivary amylase and the impact of extreme heat.
Salivary amylase is a protein enzyme designed to function optimally around body temperature (37∘C37^\circ\text{C}).
Enzyme activity depends heavily on its specific three-dimensional tertiary structure and active site shape.
2
Analyze the biological effect of boiling (100∘C100^\circ\text{C}) on protein enzymes.
High temperatures break chemical bonds holding the tertiary protein structure together, leading to irreversible denaturation.
Once denatured, the active site can no longer bind its substrate (starch), so catalysis cannot take place even after cooling back to 37∘C37^\circ\text{C}.

Anahtar Kavram

Effect of Temperature on Digestive Enzyme Structure and Function
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Konular

Animal Nutrition and Digestive System

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