Which substance is commonly demonstrated by PAS stain because it contains carbohydrates?

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Multiple Choice

Which substance is commonly demonstrated by PAS stain because it contains carbohydrates?

Explanation:
Periodic acid–Schiff detects carbohydrates by oxidizing them to aldehydes with periodic acid, then Schiff reagent binds to those aldehydes to produce a magenta color. Glycogen is a carbohydrate polymer stored in cells, so it shows strong PAS positivity. A diastase-digestion step can remove glycogen, causing loss of PAS staining, which helps confirm glycogen as the source of the positivity. The other substances listed are proteins or lipids and do not provide the carbohydrate-rich structure that PAS highlights, so they do not stain with PAS in the same characteristic way.

Periodic acid–Schiff detects carbohydrates by oxidizing them to aldehydes with periodic acid, then Schiff reagent binds to those aldehydes to produce a magenta color. Glycogen is a carbohydrate polymer stored in cells, so it shows strong PAS positivity. A diastase-digestion step can remove glycogen, causing loss of PAS staining, which helps confirm glycogen as the source of the positivity. The other substances listed are proteins or lipids and do not provide the carbohydrate-rich structure that PAS highlights, so they do not stain with PAS in the same characteristic way.

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