Carbohydrates (3.1.1.2)
All organisms need energy. Most organisms use glucose in the process of cellular
respiration to get the energy they need. Glucose is a carbohydrate, a molecule containing
carbon, hydrogen, and oxygen arranged in a ringed structure. If a carbohydrate has only
one ring, it is called a monosaccharide. Glucose is a monosaccharide. If a carbohydrate
has two rings, it is called a disaccharide. Sucrose is a disaccharide. If a carbohydrate has
more than two rings, it is called a polysaccharide.
There are many examples of polysaccharides. Cellulose is used to make the cell
walls of plants. Humans cannot digest cellulose, but it is important to their health. It is
referred to as dietary fiber. Dietary fiber increases the movement of solid wastes through
the digestive tract, which is believed to help prevent cancer. Chitin is another
polysaccharide. It is found in the cell walls of fungi and in exoskeletons of animals like
insects and crabs. Starch is an important molecule of stored energy in plants. Glycogen
is an important molecule of stored energy in animals.
Matching
_____ 1. glucose
a. a polysaccharide found in exoskeletons
_____ 2. carbohydrate
b. a polysaccharide that gives us dietary fiber
_____ 3. monosaccharide
c. a polysaccharide that is stored energy in plants
_____ 4. disaccharide
d. a polysaccharide that is stored energy in animals
_____ 5. sucrose
e. a molecule containing carbon, hydrogen, and
_____ 6. polysaccharide
oxygen arranged in a ringed structure.
_____ 7. cellulose
f. an example of a disaccharide
_____ 8. chitin
g. an example of a monosaccharide
_____ 9. starch
h. a carbohydrate with only one ring
_____ 10. glycogen
i. a carbohydrate with two rings
j. a carbohydrate with many rings
True or False
_____ 1. Carbohydrates are a group of molecules that contain carbon, nitrogen, hydrogen
an oxygen.
_____ 2. A carbohydrate is composed in rings.
_____ 3. A monosaccharide has one ring.
_____ 4. Sucrose is an example of a monosaccharide.
_____ 5. Glucose is an example of a monosaccharide.
_____ 6. A disaccharide has many rings.
_____ 7. Starch is an example of a disaccharide.
_____ 8. Starch is an example of a polysaccharide.
_____ 9. Starch and cellulose are both made by plants.
_____ 10. Chitin and glycogen are both made by plants.
Fill in the Blank
glucose
carbohydrates
monosaccharides
disaccharides
polysaccharides
cellulose
chitin
starch
glycogen
sucrose
1. _____________________ are molecules that provide energy for organisms.
2. There are three groups of carbohydrates: _____________________,
________________________, and ________________________________.
3. _______________ is an example of a monosaccharide, a carbohydrate with only one
ring.
4. _______________ is an example of a disaccharide, a carbohydrate with two rings.
5. _________________ and ____________________ are polysaccharides used for
energy.
6. __________________ and ______________________ are polysaccharides used for
structure.
Answer the following.
1. What elements are found in carbohydrates?
2. How many rings does a monosaccharide have? What is an example?
3. How many rings does a disaccharide have? What is an example?
4. How many rings does a polysaccharide have? What is an example?