Biology I IP
Name:_______________________________
Period: ________
Carbohydrates
An important group of biological compounds are the saccharides, which are the sugars of carbohydrates.
Carbohydrates contain carbon (C), hydrogen (H), and oxygen (O). The many different types of sugars
have been grouped into three main categories: monosaccharides (single-sugar carbohydrates),
disaccharides (carbohydrates made of two linked monosaccharides), and polysaccharides (carbohydrate
chains of multiple mono- and disaccharides).
Monosaccharides (Simple Sugars)
Monosaccharides are the monomers that make up longer carbohydrate chains.
1. Examine the structural formulas for the three monosaccharides shown above. What three elements are
present in monosaccharides?
2. Write the molecular formulas for fructose and galactose. Add the proper subscripts to the following:
EXAMPLE: Glucose is C6H12O6
Fructose is C H O
Galactose is C H O
3. Compare the number of hydrogen atoms to the number of oxygen atoms in each sugar. What is the
ratio of hydrogen to oxygen (that is, how many hydrogen atoms are there for each oxygen atom) in
fructose, glucose, and galactose?
4. How does the hydrogen-to-oxygen ratio in these monosaccharides compare to the hydrogen-to-oxygen
ratio in water (H2O)?
5. Why do you think that sugars like glucose, galactose, and fructose are called carbohydrates?
Honors IP Continues on Back of Page
HONORS: Molecules of monosaccharides may have the same molecular formula but differ in threedimensional structure. This is called isomerism. Describe isomerism in your own words using the
structural formulas as a guide, as well as your own resources.
HONORS: Circle the differences between the structures of glucose, galactose, and fructose on the
structural formulas on the front of this IP.
HONORS: One of the three monosaccharides is significantly different (structurally) from the other two.
Which one, and how is it different?
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