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Ch.6 Carbohydrates Life's Sweet Molecules
Frost - General, Organic and Biological Chemistry 4th Edition
Frost4th EditionGeneral, Organic and Biological ChemistryISBN: 9780134988696Not the one you use?Change textbook
All textbooksFrost 4th EditionCh.6 Carbohydrates Life's Sweet MoleculesProblem 32a
Chapter 3, Problem 32a

Identify the following reactions as condensation or hydrolysis:
(a) two monosaccharides reacting to form a disaccharide

Verified step by step guidance
1
Understand the definitions of condensation and hydrolysis reactions: Condensation reactions involve the combination of two molecules with the loss of a small molecule, often water. Hydrolysis reactions involve the breaking of a bond in a molecule using water.
Analyze the reaction described in part (a): Two monosaccharides are reacting to form a disaccharide. This suggests that two smaller molecules are combining to form a larger molecule.
Consider whether water is involved in the reaction: In the formation of a disaccharide from two monosaccharides, a molecule of water is typically lost during the process. This is a key characteristic of a condensation reaction.
Compare the reaction to the definition of condensation: Since two molecules are combining and water is lost, this aligns with the definition of a condensation reaction.
Conclude that the reaction described in part (a) is a condensation reaction based on the combination of two monosaccharides and the loss of water.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Condensation Reaction

A condensation reaction is a chemical process where two molecules combine to form a larger molecule, releasing a small molecule, often water, as a byproduct. In the context of carbohydrates, this reaction typically occurs when two monosaccharides join to form a disaccharide, resulting in the formation of a glycosidic bond.
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Hydrolysis Reaction

Hydrolysis is a chemical reaction that involves the breaking down of a compound by the addition of water. In the case of carbohydrates, hydrolysis occurs when a disaccharide is split into two monosaccharides, breaking the glycosidic bond and utilizing water in the process. This reaction is essential for digestion and energy release.
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Glycosidic Bond

A glycosidic bond is a type of covalent bond that connects a carbohydrate (sugar) molecule to another group, which can be another carbohydrate or a different type of molecule. This bond is formed during condensation reactions and is crucial for the structure and function of polysaccharides and disaccharides in biological systems.
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Related Practice
Textbook Question

Pentoses also exist in a ring form, but they most commonly occur as furanose rings. D-Ribose exists in its furanose ring form in the nucleic acid RNA. Using the structure of D-ribose from Table 6.1, draw the furanose form of β-D-ribose.

Textbook Question

Name the glycosidic bond present in mannobiose, shown in the following figure:

Textbook Question

The sugar alcohol erythritol is often included in low-calorie sweeteners. It is 70% as sweet as table sugar. Erythritol is the reduced form of the aldotetrose erythrose. Draw erythritol.

Textbook Question

Lactulose is a disaccharide used in the treatment of chronic constipation. Its formal name is galactose β(1→4) fructose.

(a) Draw the structure of lactulose.

Textbook Question

For each of the following disaccharides, name the glycosidic bond and draw the monosaccharide units produced by hydrolysis:

(a)

Textbook Question

The sugar alcohol ribitol is a component of the vitamin riboflavin and the energy transfer molecule FAD. Ribitol is formed when the monosaccharide ribose undergoes reduction at carbon 1. Draw the structure of ribitol.