Advanced Placement (AP) Biology Practice Exam

Which of the following statements is true about disaccharides?

1. They are complex carbohydrates composed of many monomers.

2. They consist of two monomer sugars.

3. They are typically formed through hydrolysis.

4. They are always sweet in taste.

The correct answer is: They consist of two monomer sugars.

Disaccharides are carbohydrates that are formed by the combination of two monosaccharides through a process known as condensation or dehydration synthesis, where a glycosidic bond is created and water is released. This characteristic of disaccharides means they are specifically defined by the presence of two sugar units, making the statement about them being composed of two monomer sugars accurate. In contrast, complex carbohydrates, which consist of many monomers, refer to polysaccharides rather than disaccharides. The process of hydrolysis involves breaking down a compound into smaller units, which is the opposite of what occurs during the formation of disaccharides. Furthermore, while many disaccharides can have a sweet taste, not all disaccharides are sweet, ruling out the statement regarding sweetness as universally true.