Textbook Question
If one sweetener packet of Splenda, Sweet’N Low, or Equal has the same sweetness as two tablespoons of sugar, according to Table 6.2, which of the packets contains the smallest amount of the sweetener?
Ch.6 Carbohydrates Life's Sweet Molecules
Frost4th EditionGeneral, Organic and Biological ChemistryISBN: 9780134988696
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Table of contents
- Ch.4 Introduction to Organic Compounds75
- Ch.5 Chemical Reactions19
- Ch.6 Carbohydrates Life's Sweet Molecules62
- Ch.7 States of Matter and Their Attractive Forces8
- Ch.8 Solution Chemistry Sugar and Water Do Mix4
- Ch.10 Proteins Workers of the Cell89
- Ch.11 Nucleic Acids Big Molecules with a Big Role69
- Ch.12 Food as Fuel An Overview of Metabolism65
Frost4th EditionGeneral, Organic and Biological ChemistryISBN: 9780134988696Not the one you use?Change textbook
Chapter 3, Problem 38a
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.
Verified step by step guidance1
Understand the structure of lactulose: Lactulose is a disaccharide composed of galactose and fructose linked by a β(1→4) glycosidic bond. This means the bond connects the 1st carbon of galactose to the 4th carbon of fructose.
Draw the structure of galactose: Galactose is a hexose sugar with the molecular formula C₆H₁₂O₆. It has an aldehyde group (-CHO) at the first carbon and hydroxyl groups (-OH) attached to the other carbons in a specific orientation.
Draw the structure of fructose: Fructose is also a hexose sugar with the molecular formula C₆H₁₂O₆. It has a ketone group (C=O) at the second carbon and hydroxyl groups (-OH) attached to the other carbons in a specific orientation.
Link galactose and fructose: Use a β(1→4) glycosidic bond to connect the hydroxyl group on the 1st carbon of galactose to the hydroxyl group on the 4th carbon of fructose. Ensure the bond orientation matches the β configuration.
Finalize the structure: Verify that all atoms are correctly bonded, the glycosidic linkage is properly drawn, and the stereochemistry of galactose and fructose is accurate. Label the carbons and functional groups for clarity.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Disaccharides
Disaccharides are carbohydrates formed by the combination of two monosaccharides through a glycosidic bond. In the case of lactulose, it consists of galactose and fructose. Understanding disaccharides is essential for grasping how they function in the body, including their role in digestion and their effects on conditions like constipation.
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Types of Disaccharides Concept 1
Glycosidic Bond
A glycosidic bond is a type of covalent bond that links a carbohydrate (sugar) molecule to another group, which can also be a carbohydrate. This bond is formed during a dehydration reaction, where a water molecule is released. Recognizing how glycosidic bonds form and their significance in carbohydrate structure is crucial for drawing and understanding the structure of lactulose.
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Chemical Structure Representation
Chemical structure representation involves illustrating the arrangement of atoms within a molecule, including bonds and functional groups. For lactulose, this means accurately depicting the two sugar units and their connections. Mastery of structural representation is vital for visualizing molecular interactions and predicting the behavior of compounds in biological systems.
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Related Practice
Textbook Question
Based on the sweetness index in Table 6.2, if you tasted a drop of each of the syrups below, which would taste the sweetest?
(a) light corn syrup (100% glucose)
Textbook Question
Name the glycosidic bond present in mannobiose, shown in the following figure:
Textbook Question
Identify a disaccharide that fits each of the following descriptions:
(a) ordinary table sugar
Textbook Question
Identify the following reactions as condensation or hydrolysis:
(a) two monosaccharides reacting to form a disaccharide
Textbook Question
For each of the following disaccharides, name the glycosidic bond and draw the monosaccharide units produced by hydrolysis:
(a)