교과서 질문
Draw a structure for a compound that meets each of the following descriptions:
b. An aldehyde with four carbons
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Ch.15 Aldehydes and Ketones
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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TOC.tableOfContents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187당신이 사용하는 게 아니라요?교과서 변경
15장, 문제 24
Glucose is the major sugar in mammalian blood. We often see it represented as either the "free aldehyde" or the cyclic hemiacetal forms shown here. Of the two forms of glucose, the cyclic hemiacetal is the preferred form found in blood. Can you suggest two reasons why?
검증된 단계별 안내1
The first reason why the cyclic hemiacetal form of glucose is preferred in blood is due to its stability. The cyclic structure forms a six-membered ring (pyranose), which is more thermodynamically stable compared to the open-chain free aldehyde form. This stability arises because the ring structure minimizes the exposure of the reactive aldehyde group, reducing its likelihood of participating in unwanted side reactions.
The second reason is related to the reactivity of the aldehyde group in the free aldehyde form. Aldehydes are highly reactive and can easily undergo oxidation or react with other molecules in the bloodstream. By forming the cyclic hemiacetal, the aldehyde group is converted into a less reactive hydroxyl group, making the molecule less prone to undesirable chemical reactions in the biological environment.
The cyclic hemiacetal form also allows glucose to exist in equilibrium between its alpha and beta anomers (anomeric forms), which is important for its biological functions. This equilibrium is not possible in the free aldehyde form.
The formation of the cyclic hemiacetal is an intramolecular reaction, where the hydroxyl group on carbon 5 reacts with the aldehyde group on carbon 1. This reaction is energetically favorable and occurs spontaneously in aqueous solutions, such as blood.
In summary, the cyclic hemiacetal form is preferred because it is more stable, less reactive, and better suited for the biological environment of the bloodstream, where glucose plays a critical role in energy metabolism.
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주요 개념
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Cyclic Hemiacetal Formation
Glucose can exist in two forms: an open-chain form (free aldehyde) and a cyclic form (cyclic hemiacetal). The cyclic form is formed when the aldehyde group reacts with a hydroxyl group on the same molecule, creating a stable ring structure. This transformation is energetically favorable and results in a more stable configuration, which is crucial for its biological functions.
추천 영상:
가이드 코스
2:55
Cyclic Hemiacetals Concept 2
Stability in Aqueous Solutions
In biological systems, glucose predominantly exists in aqueous environments, such as blood. The cyclic hemiacetal form is more stable in these conditions due to reduced steric hindrance and the formation of intramolecular hydrogen bonds. This stability minimizes the likelihood of glucose reverting to its less stable open-chain form, ensuring efficient transport and utilization in metabolic processes.
추천 영상:
가이드 코스
01:39Solutions
Biological Function and Reactivity
The cyclic hemiacetal form of glucose is not only more stable but also plays a critical role in its reactivity and interaction with enzymes. This form allows glucose to participate effectively in various biochemical pathways, such as glycolysis and cellular respiration. The ability to readily convert between forms also facilitates its role as a substrate for energy production in cells.
추천 영상:
가이드 코스
02:16Logarithmic Functions
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교과서 질문
The carbonyl group can be reduced by addition of a hydride ion (H–) and (H+) a proton. Removal of H– and H+ from an alcohol results in a carbonyl group.
a. To which atom of the carbonyl is the hydride ion added and why?
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교과서 질문
The carbonyl group can be reduced by addition of a hydride ion (H–) and (H+) a proton. Removal of H– and H+ from an alcohol results in a carbonyl group.
b. In the reaction, indicate which direction represents reduction and which represents oxidation.
895
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교과서 질문
Draw a structure for a compound that meets each of the following descriptions:
c. An alpha-bromoaldehyde, C4H7BrO
840
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교과서 질문
A fundamental difference between aldehydes and ketones is that one can be oxidized to carboxylic acids but the other cannot. Which is which? Give an example of a test to differentiate aldehydes from ketones.
794
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교과서 질문
Draw a structure for a compound that meets each of the following descriptions:
a. A 6-carbon cyclic ketone with a methyl group on the beta carbon
1002
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