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Questions and Answers
What is the basis of the test for identifying carbohydrates from other macromolecules?
What is the basis of the test for identifying carbohydrates from other macromolecules?
- Intensity of color directly proportional to carbohydrate amount
- Formation of purple-colored furfural or hydroxymethylfurfural derivatives
- Rapid positive test for monosaccharides
- Reaction of alpha-naphthol with carbohydrates in the presence of sulfuric acid (correct)
What is the specific characteristic of monosaccharides in this test?
What is the specific characteristic of monosaccharides in this test?
- Their color intensity is directly proportional to the amount present
- They form purple-colored derivatives
- They give a rapid positive test (correct)
- They react slower than disaccharides and polysaccharides
What causes the formation of purple-colored furfural or hydroxymethylfurfural derivatives in the test?
What causes the formation of purple-colored furfural or hydroxymethylfurfural derivatives in the test?
- Reaction of disaccharides and polysaccharides with alpha-naphthol
- Presence of sulfuric acid alone
- Sugars reacting with alpha-naphthol in an acidic environment (correct)
- Direct proportionality of color intensity to carbohydrate amount
Starch gives a reddish brown complex with iodine in this test
Starch gives a reddish brown complex with iodine in this test
Glycogen reacts to form blue color with iodine in this test
Glycogen reacts to form blue color with iodine in this test
The purpose of this test is to differentiate polysaccharides from other carbohydrates
The purpose of this test is to differentiate polysaccharides from other carbohydrates
Study Notes
Test for Identifying Carbohydrates
- Tests for carbohydrates differentiate them from other macromolecules based on specific reactivity and color changes.
- Different tests exploit unique properties of carbohydrates to reveal their presence.
Characteristic of Monosaccharides
- Monosaccharides show distinct reactivity and participate in specific reactions, differentiating them from polysaccharides and other macromolecules.
Formation of Derivatives
- The formation of purple-colored furfural or hydroxymethylfurfural derivatives is induced by the dehydration of sugars during the test, leading to color changes indicative of sugar presence.
Starch and Iodine Reaction
- Starch forms a reddish-brown complex when reacted with iodine, a characteristic color indicating the presence of this polysaccharide.
Glycogen and Iodine Reaction
- Glycogen produces a blue color when treated with iodine, differentiating it from starch and highlighting its unique structure and composition in polysaccharides.
Purpose of the Test
- The main purpose of the test is to differentiate polysaccharides from other carbohydrate types, allowing for specific identification and analysis.
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Description
Test your knowledge of identifying carbohydrates using chemical reactions. Learn about the reactions of different types of carbohydrates with alpha-naphthol and sulfuric acid, and the resulting color changes.
