Which statement correctly describes enzyme demonstration use of frozen sections?

• A. Frozen sections are specified for demonstration of most enzymes.
• B. Frozen sections are not useful for enzyme demonstration.
• C. Paraffin sections are preferred for demonstrating enzymes.
• D. Enzyme demonstration requires dehydration first.

Answer: (A)

Enzyme demonstrations in tissue rely on keeping the enzyme activity intact. Frozen sections preserve that activity because they skip the fixation and dehydration steps that inactivate many enzymes during paraffin processing. By cutting unfixed or lightly fixed cryosections and exposing them to specific substrates, you can visualize where the enzyme is active in the tissue. That’s why frozen sections are specified for demonstrating most enzymes. In contrast, paraffin sections require dehydration and fixation, which destroy enzyme activity, so they’re not the preferred method for many enzyme demonstrations; dehydration itself is not needed and would hinder the reaction.