Name ___________________________________ Date ______________ Block _________
Carbohydrates: Chemistry & Identification
Sugar, the building block of carbohydrates!!
Carbohydrates are molecules made up of smaller molecules called sugars. The major function of
carbohydrates in the body is for “quick energy”. There are 3 sizes of carbohydrates depending on
the amount of sugars included in the carbohydrate.
1. Give the adjective for each of the following carbohydrates according to the amount of sugars in
the molecule.
a. 1 sugar: ___________________________________
b. 2 sugars: __________________________________
c. Many sugars: _______________________________
Carbohydrates are made of the elements: carbon, hydrogen, and oxygen. The hydrogen and
oxygen are in a ratio of 1:2 no matter what size of carbohydrate is being discussed. Refer to figure
below for the structural formulas of 3 of the single sugar carbohydrate molecules.
2. What is the molecular formula for the the following monosaccharides?
a. glucose: C ____ H ____ O _____
b. fructose: C ____ H ____ O _____
c. galactose: C ____ H ____ O _____
3. What do you notice about the ratio of hydrogen to oxygen in each monosaccharide? _____
4. What is the ratio of hydrogen to oxygen in the molecule water? __________________________
5. What do you notice about all of the monosaccharide molecular formulas?
___________________________________________________________________________
6. What is the difference between the monosaccharides? ________________________________
7. What do the straight lines between the atoms in each molecule represent? ________________
8. What does it mean when there are two lines in between atoms? _________________________
9. When you put atoms together with the straight lines, are you storing or releasing energy?
______________________________________________________________________________
10. What functional group is contained in a carbohydrate? _______________________________
When you want to make a disaccacharide, you must remove a hydroxyl group from one
monosaccharide and a hydrogen atom from another. This leaves a place open on each of the
molecules then to connect to each other. This process is called dehydration synthesis. Humans
usually do this when they have already digested plant polysaccharides into their monosaccharides
and now they want to make human disaccharides or polysaccharides.
11. In the figure below, what are the monosaccharides represented? _______________________
12. What molecule has to be removed in the figure below in order to connect the two
monosaccharides? ______________________________________________________________
13. What is the name of the process shown in the figure below? __________________________
Name of
process
shown here?