Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

9. Carbohydrates

Reducing Sugars Tests

Biochemistry

9. Carbohydrates

Reducing Sugars Tests

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Multiple Choice

Which of these statements is false?

The Fehling's test allows us to detect the presence of reducing sugars.

The Benedict's test allows us to detect the presence of sugars with a free aldehyde or ketone group.

All simple, linear monosaccharides are reducing sugars.

All disaccharides have exposed carbonyl groups and are also reducing sugars.

Sucrose and other non-reducing sugars will not react with Tollens' solution.

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Verified step by step guidance

Understand the concept of reducing sugars: Reducing sugars are carbohydrates that can donate electrons to another molecule, typically through their free aldehyde or ketone group. This property allows them to reduce certain chemical reagents, such as those used in Fehling's, Benedict's, and Tollens' tests.

Review the Fehling's test: Fehling's test is used to detect the presence of reducing sugars. It involves the reduction of copper(II) ions to copper(I) oxide, which forms a red precipitate. This test is positive for sugars with free aldehyde groups.

Examine the Benedict's test: Similar to Fehling's test, Benedict's test detects reducing sugars. It uses copper(II) sulfate in an alkaline solution, which is reduced to copper(I) oxide, forming a red precipitate. This test is positive for sugars with free aldehyde or ketone groups.

Consider the statement about monosaccharides: All simple, linear monosaccharides are reducing sugars because they have free aldehyde or ketone groups that can participate in redox reactions.

Evaluate the statement about disaccharides: Not all disaccharides are reducing sugars. For example, sucrose is a non-reducing sugar because its glycosidic bond involves the aldehyde group of glucose and the ketone group of fructose, preventing them from reacting with Tollens' solution or other similar reagents.