Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

20. Carbohydrates

Cyclic Structures of Monosaccharides

GOB Chemistry

20. Carbohydrates

Cyclic Structures of Monosaccharides

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3:21 minutes

Problem 35a

Textbook Question

Identify each of the following as the α or ß isomer:
a.

Verified step by step guidance

Step 1: Understand the difference between α (alpha) and ß (beta) isomers. These terms are used to describe the orientation of the hydroxyl (-OH) group attached to the anomeric carbon in cyclic forms of carbohydrates. In the α-isomer, the -OH group on the anomeric carbon is on the opposite side of the ring relative to the CH₂OH group. In the ß-isomer, the -OH group is on the same side as the CH₂OH group.

Step 2: Locate the anomeric carbon in the given structure. The anomeric carbon is the carbon that was part of the carbonyl group (C=O) in the linear form of the sugar and is now bonded to two oxygen atoms in the cyclic form.

Step 3: Identify the orientation of the hydroxyl (-OH) group attached to the anomeric carbon. Check whether it is pointing in the same direction or the opposite direction relative to the CH₂OH group on the reference carbon (usually carbon 5 in hexoses).

Step 4: Compare the orientation of the -OH group on the anomeric carbon to the CH₂OH group. If the -OH group is on the opposite side of the ring as the CH₂OH group, it is the α-isomer. If it is on the same side, it is the ß-isomer.

Step 5: Based on the analysis of the image provided, classify the structure as either the α or ß isomer. Ensure to double-check the orientation to confirm your identification.

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Key Concepts

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

Alpha (α) and Beta (β) Isomers

Alpha (α) and beta (β) isomers refer to the two different configurations of cyclic sugars, particularly in the context of anomeric carbon. In α-isomers, the hydroxyl group on the anomeric carbon is positioned on the opposite side of the ring from the CH2OH group, while in β-isomers, it is on the same side. This distinction is crucial for understanding the reactivity and properties of carbohydrates.

Anomeric Carbon

The anomeric carbon is the carbon atom in a sugar molecule that becomes a new chiral center when the sugar cyclizes. It is typically the carbon that was part of the carbonyl group (aldehyde or ketone) in the linear form of the sugar. The configuration of the anomeric carbon determines whether the sugar is in its α or β form, influencing its biological function and interactions.

Cyclic Sugar Structures

Cyclic sugar structures are formed when the hydroxyl group of a sugar reacts with its own carbonyl group, resulting in a ring formation. This process is essential for the stability and functionality of sugars in biological systems. Understanding the cyclic forms of sugars, including their α and β configurations, is fundamental for studying carbohydrate chemistry and metabolism.

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Textbook Question

In its open-chain form, D-mannose, an aldohexose found in orange peels, has the structure shown here. Coil mannose around and draw it in the cyclic hemiacetal ⍺ and β forms.

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Textbook Question

D-Fructose can form a six-membered cyclic hemiacetal as well as the more prevalent five-membered cyclic form. Draw the α isomer of D-fructose in the six-membered ring.

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Textbook Question

What are the kind and number of atoms in the ring portion of the Haworth structure of glucose?

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Textbook Question

Draw the Haworth structures for α- and ß-D-glucose.

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Textbook Question

The sugar d-gulose is a sweet-tasting syrup.