Type Flashcards
(25 cards)
Qu’est-ce qu’une liaison glycosidique?
Une liaison covalente formée entre le carbone anomérique d’un ose et un groupement hydroxyle, amine ou thiol d’une seconde molécule.
Quels types de liaisons glycosidiques existent?
O-glycosidique, N-glycosidique, S-glycosidique.
Quel type de liaison est formé dans les polymères d’oses?
Des liens O-glycosidiques.
Que se passe-t-il lorsque le carbone anomérique d’un ose forme une liaison glycosidique?
Il n’y a plus de mutarotation et la configuration anomérique est gelée.
Quelle est la configuration du carbone anomérique pour une liaison α glycosidique?
Carbone anomérique gelé en position α.
Quelle est la configuration du carbone anomérique pour une liaison β glycosidique?
Carbone anomérique gelé en position β.
Vrai ou faux: La formation d’une liaison glycosidique permet la linéarisation de l’ose.
Faux.
Complétez: Les résidus d’oses dans les polymères sont liés par des _______.
liens O-glycosidiques.
What are holosides?
Polymers formed exclusively of oses or derivatives of oses linked by O-glycosidic bonds
Holosides consist of monosaccharides linked together, which can vary in structure and complexity.
How are O-glycosidic bonds formed?
Between the anomeric carbon of one ose and a hydroxyl group of another ose
This type of bond is crucial for the formation of disaccharides and polysaccharides.
What does the versatility of the glycosidic bond indicate?
It leads to a great diversity of holosides
The various configurations and linkage possibilities contribute to the structural diversity of carbohydrates.
How many possible glycosidic linkages can be formed between two oses?
10 possible linkages
This is due to the anomeric carbon’s ability to link with multiple hydroxyl groups and its configuration.
What configurations can the anomeric carbon take before forming a glycosidic bond?
α or β configuration
The choice of configuration affects the properties and digestibility of the resulting glycosidic bond.
How is a glycosidic bond described?
By indicating the anomeric configuration followed by the carbon atom numbers involved
This notation helps in identifying the specific type of bond and its structure.
How are holosides categorized?
According to the number of residues they contain
The main categories are monosaccharides, disaccharides, and polysaccharides.
What are disaccharides made of?
2 residues of oses or derivatives of oses linked together
Disaccharides are a common form of sugar, such as sucrose and lactose.
Fill in the blank: Holosides are linked by _______.
O-glycosidic bonds
This type of bond is essential for carbohydrate structure.
What are holosides?
Polymers formed exclusively of sugars or sugar derivatives linked by O-glycosidic bonds.
Holosides consist of monosaccharides connected through glycosidic linkages.
How are O-glycosidic bonds formed?
Between the anomeric carbon of one sugar and a hydroxyl group of another sugar.
This type of bond is crucial for the formation of disaccharides and polysaccharides.
What is the significance of the versatility of glycosidic bonds?
It explains the great diversity of holosides.
Different configurations and bonding options lead to a variety of polysaccharides.
How many possibilities of glycosidic linkages exist between two sugars?
10 possibilities.
This is due to the five hydroxyl groups on the second sugar and the two anomeric configurations (α and β) of the first sugar.
What is indicated when describing a glycosidic bond?
The anomeric configuration followed by the carbon atom numbers involved.
This notation helps in identifying the specific type of glycosidic linkage.
Fill in the blank: The carbon anomeric of the first sugar can take the configuration _______ or _______ before forming the bond.
α, β
True or False: The diversity of holosides is solely due to the number of different sugars involved.
False
