DISACCHARIDES: Definition and Formation via Glycosidic Bonds

In disaccharide formation, a glycosidic bond always forms between the anomeric carbon of the first sugar and a non-anomeric carbon of the second sugar.

• TRUE

• FALSE

Disaccharides consist of two monosaccharide units joined together by a glycosidic bond

• TRUE

• FALSE

Which of the following disaccharides is non-reducing?

•  Maltose

• Sucrose

•  Lactose

• Cellobiose

Which of the following accurately describes a class of carbohydrates based solely on the number of glycosidic linkages?

• Monosaccharides: no glycosidic linkages and no carbonyl group

• Disaccharides: contain one glycosidic linkage between two monosaccharide units

• Oligosaccharides: contain fewer glycosidic linkages than disaccharides

• Polysaccharides: formed by multiple peptide linkages between sugars

Which of the following statements best compares the structures of lactose and sucrose?

• Both are composed of glucose and galactose linked by an α(1→4) glycosidic bond.

• Lactose is a non-reducing sugar, while sucrose is a reducing sugar.

• Sucrose contains a glucose and fructose linked by an α(1→2)β bond, making it non-reducing.

• Lactose is made of glucose and fructose and is more stable than sucrose.

A patient’s stool sample tests positive for reducing sugars but negative for glucose? Which disaccharide is most likely present in the stool?

• Sucrose

• Glucose

• Lactose

• Maltose

Sucrose

• Glucose + Galactose, β(1→4) bond

• Glucose + Fructose, α(1→2) bond

• Glucose + Glucose, β(1→4) bond

• Glucose + Glucose, α(1→4) bond

Maltose

• Glucose + Galactose, β(1→4) bond

• Fructose + Glucose, α(1→2) bond

• Glucose + Glucose, β(1→4) bond

• Glucose + Glucose, α(1→4) bond

Lactose is abundantly found in…

• Milk

• Bread

• Honey

• Apples

Sucrose is also known as…

• Malt sugar

• Milk sugar

• Cane sugar

• Table sugar