This activity page will offer:
into atomic arrangement of several nutrients
hands-on experience in constructing models
visualization of dehydration synthesis using molecular models
visualization of bond saturation in fat molecules
opportunity to apply critical thinking to atomic modeling
Carbohydrates are a group of nutrients that include sugars and starches.
Perhaps, the most familiar carbohydrate building block is glucose.
Glucose is a monosaccharide, which means that it contains one sugar
unit. Monosaccharides can be joined together to produce larger chains
of carbohydrates. Starch is an example of a long chain of sugar
molecules that are linked together. In this set of activities, you'll
construct a single sugar (glucose) and observe the effects of a
dehydration synthesis reaction.
Gum drops (variety of colors)*
* Or ball and stick models
Examine the study of gumdrops that you will be using to assemble
your molecular models. Now, consider the formula of glucose, C6H12O6.
Based on this formula, how should you assign specific colors to
the component atoms? (The most common color should be assigned
to hydrogen, since hydrogen atoms are the most numerous.)
build the ring version of glucose, let's construct a closed ring
formed by five carbon atoms and one oxygen atom.
let's add the sixth carbon atom. It is attached to the ring carbon
that is immediately to the left of the oxygen atom.
remaining five oxygen atoms are part of hydroxyl (OH) groups.
They are added as shown here.
the model by adding the remaining seven hydrogen atoms so that
each carbon atom forms four bonds.
produce larger carbohydrate molecules, glucose is linked to other
sugar molecules. During this bonding process, two atoms of hydrogen
and one atom of oxygen are removed from the linking sugars. These
atoms join together to produce a molecule of water. Hence, this
type of sugar bonding is called dehydration synthesis.
Construct a second model of the glucose model.
both models side-by-side.Remove the two hydrogen atoms and one
oxygen atom that are associated with dehydration synthesis (identified
by the dashed line).
the free bond of the ring oxygen atom to the free bond of the
carbon atom. Join the three removed atoms together to form a molecule
type of molecule is removed during dehydration synthesis?
happens to the "open" bonds that are created as neighboring sugar
molecules lose component atoms?
might happen if you added water to a starch molecule?
Proteins are macromolecules that are found in every living cell.
Like carbohydrates, they form a critical part of our diet. They
are also the profiled nutrient in the Atkins diet. The basic building
block of a protein molecule is an amino acid. All amino acids share
a common feature. They contain both an amine (NH2) group and a carboxyl
Glycine is the simplest structural amino acid. Like all amino
acids, it has an amine (NH2) group. Use gumdrops to construct
this functional group.
Like all amino acids, glycine also has a carboxyl (COOH) group.
Use gumdrops to construct this functional group. Remember to
retain consistency in your assignment of gumdrop colors.
amine and acid group are both attached to a central carbon atom.
The remaining two bonds of this backbone carbon are saturated
with hydrogen. Your finished glycine model should resemble this
are common features to all amino acids?
Compare and contrast the composition of an amino acid to a sugar.
what you can observe in the molecular structure, can dehydration
synthesis also produce long chains of amino acids? Explain.
and Unsaturated Fats
Although you may not know what they are, chances are you've heard
of saturated and unsaturated fats. Fats are long molecules that
can have more than 20 carbon atoms in their backbone. A saturated
fat has only single bonds in its carbon backbone. An unsaturated
fat has one or more double bonds.
a chain of four carbon atoms.
Add two hydrogen atoms to each carbon atom. Place a toothpick
at both ends of the chain to represent the bond that connects
this section to the rest of the fat molecule.
Now construct a version of this carbon backbone that contains
an unsaturated carbon.
saturated, to how many different atoms can a carbon bond?
must be added to an unsaturated chain, in order to make it saturated?
Infer the structural feature of a "polyunsaturated fat."
There are all sorts of computer molecular modeling programs
on the web. Many are free to use and offer powerful construction
and manipulation tools. Check
out some of these free tools at http://ep.llnl.gov/msds/dvc/viewrs.html.
For MACs running under OS X, iMOL is a powerful program that you
it at http://www.pirx.com/iMol.
Models From a 2D Image
By "freeviewing" two side-by-side images, you can experience
the stereoscopic illusion of depth. This technique is sometimes
used by scientists to help illustrate three dimensional layout of
out this URL
for some screen-popping examples of the freeviewing effect:
Use the Internet and print resources to identify additional
types of molecules that play a role in nutrition. Then, using either
computer-assisted drawing programs or common materials construct
models of these atomic arrangements. From their composition and
structure, make inferences about their role in nutrition.
A reference to the biochemistry of various nutrients and diets.
A comprehensive overview of constructing a variety of glucose molecules
including straight chain and isomer examples.
of the Atom
An overview of fats in the diet presented by the University of Michigan
Advisors for this Guide:
Suzanne Panico, Science Teacher Mentor, Cambridge Public Schools,
Anne E. Jones, Science Department, Wayland Middle School, Wayland,
Gary Pinkall, Middle School Science Teacher, Great Bend Public Schools,
Great Bend, KS
Cam Bennet Physics/Math Instructor Dauphin Regional Comprehensive
Secondary School Dauphin, MB Canada