Chapter 5.2 talks about carbohydrates that provide fuel and building materials. Carbohydrates are organic compounds that are made of sugar molecules and there are different kinds of sugars. One kind of a sugar are the simple sugars also known as monosaccharides, such as glucose and frutose, others are disaccharides, which is basically two monosaccharides joined together. There are also a kind of long polymer chains that are composed of simple sugar monomers are called polysaccharides. One example of a polysaccharide is known as starch that is found in plant cells that acts as sugar stockpiles. Animal cells on the other hand, do not contain starch and they store excess sugar in the form of a polysaccharide known as glycogen. There are other kinds of polysaccharides, such as cellulose that acts as building materials. All the carbohydrates are hydrophilic, due to the many hydroxyl groups in their sugar units.
Images:
http://www.mun.ca/biology/scarr/Ribose_sugar.html
(Displays the structure of sugar atoms particularly Ribose)
http://www.mcb.mcgill.ca/~hallett/GEP/Lecture1/Image6.gif
(Displays the structure of Glucose)
For more information:
http://en.wikipedia.org/wiki/Sugar under the Chemistry section
Concept Check:
Explain the differences between a monosaccharide and a disaccharide. Give an example of each.
An example of a monosaccharide is glucose and an example of disaccharide is sucrose.
Compare and contrast starch, glycogen, and cellulose.
Starch is a polysaccharide found in plant cells that consists entirely of glucose monomers, glycogen is a polysaccharide that has a chain that is more highly branched than a starch polymers. Cellulose is a polysaccharide that can be linked together with hydrogen bonds, forming cable-like fibers in the tough walls that enclose plant cells.
How do animals store excess glucose molecules?
Animals store excess glucose molecules in the glycogen.
