Question

Sucrose and lactose are two carbohydrates that have the same molecular formula (C₁₂H₂₂O₁₁). Which of the following describes why sucrose and lactose have different properties?

1) They are made up of different amino acids.
2) They are monosaccharides with different atoms bonded to their rings.
3) They each have two glucose molecules, but the arrangement differs.
4) They are made of different combinations of monosaccharides.

Answer 1

Sucrose and lactose have different properties because they are composed of different combinations of monosaccharides: sucrose is a molecule of glucose and fructose, and lactose is a molecule of glucose and galactose.

Step-by-step explanation:

The question you've asked pertains to why sucrose and lactose, despite having the same molecular formula (C₁₂H₂₂O₁₁), exhibit different properties. The answer is they are made of different combinations of monosaccharides. Sucrose is composed of glucose and fructose, whereas lactose consists of glucose and galactose. These monosaccharides are classified as isomers, meaning they have the same chemical formula but their atoms are arranged differently, leading to distinct structural properties.

Additionally, the type of glycosidic bond that links the monosaccharides differs between sucrose and lactose, which influences their reactivity, how they are broken down in the body, and consequently, their properties. Therefore, option 4 correctly states that sucrose and lactose are indeed made of different combinations of monosaccharides, imparting them with their unique characteristics.