Student misconceptions with Protein Structure and Function.
Protein composition: (Proteins are made of amino acids)
There is a problem with the interchange and incorrect use of “Amino Acids” and
“Proteins” as vocabulary. Also, a few stated that “proteins are amino acids” or “that
enzymes and amino acids fit together”
Students tend to think of proteins as something to be eaten! The connection between
”protein” as food and “protein as structural and functional machines” in the body hasn’t
been fully made. The whole “proteins are eaten and digested into amino acids,
transported to cells to be turned into other proteins useful to the organism” storyline is
weak and needs re-enforcement (the “collective protein” in the diet is converted into
“specific proteins” for the metabolic networks.
Enzyme function: (Enzymes are proteins with a catalytic function)
The 3D model of Insulin, finished off with paperclips then shaken to disrupt the weaker
bonds was highly effective is getting across the concept of heat altering the shape and
therefore the function of proteins.
Some students stated that:
 Heat changes the structure of amino acids (NO: heat changes the structure of
proteins)
 Enzymes only work on sugars (NO: there are thousands of other examples that
work on other substrates)
 Enzymes break down food (Actually some enzymes do! For example amylase in
your saliva starts to break down starch. Just be sure you are clear that you
understand that isn’t their only role!)
Students forget that it is the affinity between the functional groups on the amino acids
that affects the shape (and therefore the function) of the protein.
The Importance of Proteins: (The proteins of your body are either structural or
perform some kind of work. They are made of amino acids that you obtain from
your diet)
Students stated that:
 They are good for you. (WHY)
 You need them to be healthy (WHY) and build muscle (HOW).
Many students neglected to offer an explanation and fail to fully demonstrate their
understanding.
REMEMBER:
Proteins are the machines of a living cell.
1. Like machines they each have a specific function.
2. Like machines they are reusable (but not infinitely so).
3. Like machines they do work (either structural work or mechanical work).
4. Like machines their shape determines what they do and how well they do
it.