http://www.ck12.org Chapter 26. Biochemistry
26.1 Carbohydrates
Lesson Objectives
- Describe the general structures of the simple sugars, glucose and fructose.
- Describe how two simple sugars can be linked to form a disaccharide.
- Compare the simple sugar components of sucrose, lactose, and maltose.
- Identify the structure and function of the polysaccharides starch, glycogen, and cellulose.
Lesson Vocabulary
- carbohydrates
- disaccharide
- monosaccharide
- polysaccharide
Check Your Understanding
Recalling Prior Knowledge
- What are aldehydes, ketones, and alcohols?
- What is the relationship between monomers and polymers?
Carbohydrates constitute a class of compounds that serves many functions in living organisms. Among the most
important is the storage of energy in the form of starch and glycogen. Carbohydrates can also act as structural
components, such as cellulose in plants, and are a part of the important genetic molecules DNA and RNA. In this
lesson, you will learn about the basic structures and functions of carbohydrates.
Monosaccharides
Some foods that are high in carbohydrates include bread, pasta, and potatoes. Endurance athletes often prepare for
competition by consuming large amounts of carbohydrate-heavy foods to allow them to perform at a high level for
long periods of time (Figure26.1).
The term carbohydrate comes from the fact that the majority of carbohydrates contain carbon, hydrogen, and oxygen
in a ratio of 1:2:1, making for an empirical formula of CH 2 O. This is somewhat misleading, because the molecules
are not actually hydrates of carbon at all. Carbohydratesare monomers and polymers of aldehydes and ketones
that have multiple hydroxyl groups attached.