http://www.ck12.org Chapter 26. Biochemistry
- Two monosaccharides can be joined together in a condensation reaction to form a disaccharide, such as
sucrose, lactose, or maltose. - Starch is a polysaccharide of glucose monomers that stores energy in plants. Glycogen stores energy in
animals. - Cellulose is another polysaccharide of glucose, but it is indigestible to most organisms and serves as a
structural component in plants.
Lesson Review Questions
Reviewing Concepts
- What is the origin of the term carbohydrate, and why is it potentially misleading?
- What are some of the main functions of carbohydrates in nature?
- What functional groups are present in glucose? In fructose?
- Describe the reaction by which monosaccharides combine to form a disaccharide.
- Which monosaccharides combine to form the following disaccharides?
a. lactose
b. maltose
c. sucrose - What are the two main components of starch? Describe their differences.
- What is the difference in function between starch and glycogen?
- Starch is digestible while cellulose is not. Explain this difference.
Problems
- Write a molecular equation for the formation of sucrose from simple sugars.
- 20.0 g of sucrose is dissolved in 100.0 mL of water.
a. What is the molarity of the solution?
b. If the sucrose were completely hydrolyzed, what mass of glucose could be isolated?
Further Reading / Supplemental Links
- TheChemistryofCarbohydratesFoundinFood, http://www.medbio.info/Horn/Time%201-2/CarbChem1.htm
- Carbohydrates–ChemicalStructure, http://www.scientificpsychic.com/fitness/carbohydrates.html
Points to Consider
Proteins are polymers of another class of biomolecules called amino acids.
- How many naturally occurring amino acids are used to form proteins?
- What is the function of an enzyme in biological reactions?