Ch.13 Carbohydrates

Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition

Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook

Timberlake 13th Edition

Ch.13 Carbohydrates

Problem 9a

Chapter 13, Problem 9a

Classify each of the following monosaccharides as an aldopentose, ketopentose, aldohexose, or ketohexose:
a. Psicose is present in low amounts in foods.

Verified step by step guidance

Identify the functional group of the monosaccharide. Aldoses contain an aldehyde group (-CHO) at the first carbon, while ketoses contain a ketone group (C=O) typically at the second carbon.

Determine the number of carbon atoms in the monosaccharide. Pentoses have 5 carbon atoms, while hexoses have 6 carbon atoms.

Combine the functional group classification (aldo- or keto-) with the number of carbons (-pentose or -hexose) to classify the monosaccharide.

For Psicose, examine its structure (if provided in the image) to identify whether it has an aldehyde or ketone group and count the number of carbon atoms.

Based on the functional group and carbon count, classify Psicose as either an aldopentose, ketopentose, aldohexose, or ketohexose.

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Key Concepts

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

Monosaccharides

Monosaccharides are the simplest form of carbohydrates, consisting of single sugar molecules. They can be classified based on the number of carbon atoms they contain and the type of carbonyl group present, which can either be an aldehyde or a ketone. Common examples include glucose and fructose, which serve as fundamental building blocks for more complex carbohydrates.

Aldoses and Ketoses

Aldoses are monosaccharides that contain an aldehyde group (-CHO), while ketoses contain a ketone group (C=O). This distinction is crucial for classifying sugars, as it affects their chemical properties and reactivity. For instance, glucose is an aldohexose, whereas fructose is a ketohexose, highlighting the importance of the functional group in determining the sugar's classification.

Pentoses and Hexoses

Pentoses are monosaccharides with five carbon atoms, while hexoses have six. The classification into pentoses and hexoses is essential for understanding the structure and function of these sugars in biological systems. Examples include ribose (a pentose) and glucose (a hexose), both of which play vital roles in metabolism and cellular processes.

Classify each of the following monosaccharides as an aldopentose, ketopentose, aldohexose, or ketohexose:a. Psicose is present in low amounts in foods.