ketose
Học thuậtThân thiện
Definition
Noun: A ketose is any monosaccharide sugar whose molecule contains a ketone group (C=O) or its cyclic hemiacetal form. This distinguishes it from an aldose, which contains an aldehyde group.
Usage
Ketoses are a fundamental class of simple sugars in biochemistry. The term is used to classify sugars based on their carbonyl functional group. * Fructose is a common ketose found in fruits and honey. * In metabolism, the ketose ribulose is an important intermediate in the Calvin cycle. * Biochemists test for ketoses using specific chemical reactions like Seliwanoff's test.
Advanced Usage
- Structural Isomerism: A ketose and an aldose with the same number of carbon atoms (e.g., fructose and glucose) are functional group isomers.
- Tautomerization: In solution, ketoses can exist in equilibrium between their open-chain ketone form and cyclic furanose or pyranose hemiacetal forms.
Variants and Related Words
- Ketosis (n): A metabolic state characterized by elevated levels of ketone bodies in the blood, not directly related to dietary ketose sugars.
- Aldose (n): The complementary class of monosaccharides containing an aldehyde group.
- Triose, Tetrose, Pentose, Hexose: Terms that classify monosaccharides by the number of carbon atoms (e.g., a "ketohexose" like fructose).
Synonyms
- Keto sugar
- Monosaccharide ketone
Related Phrases
- Reducing sugar: Most ketoses are reducing sugars due to the presence of a potentially free anomeric carbon in their hemiacetal form.
- Keto-enol tautomerism: The chemical equilibrium relevant to the structure of ketoses.
Noun
- any monosaccharide sugar that contains a ketone group or its hemiacetal