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Proteins Review
Proteins
This structure represents a polymer.
1. What are the individual units called?
They are called monomers
Proteins
2. What does poly mean?
Poly means ‘many’ and polymer
means ‘many pieces.’
3. What does mono mean?
Mono means ‘one’ and monomer
means ‘one piece.’
Proteins
This structure represents a protein.
4. What kind of molecule makes up its
monomers?
The amino acid
Proteins
This structure represents a protein.
5. What are the bonds that link the
amino acid monomers called?
The bonds are peptide linkages
Proteins
This structure represents a protein.
6. Proteins can be made of one or more
strands of amino acids. What is the name
given to a single strand of amino acids?
Individual strands are called polypeptides
Proteins
This structure represents a protein.
7. What molecule is released when an amino
acid is added to the polypeptide?
(Click once to see animation)
A water molecule is released
Proteins
This structure represents a protein.
8. What molecule must be added in order to
remove an amino acid from the polypeptide?
(Click once to see animation)
A water molecule is added
Proteins
9. How many different
kinds of amino acids
are common to living
things?
There are twenty
different kinds
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10. Draw the basic amino acid structure and label
its functional groups.
H
H
Amino
group
N
H
C
O
C
R
Variable group
H
Carboxyl
group
Proteins
11. Some amino acids are hydrophilic. What does
that mean?
It means the amino acids are attracted to
water.
12. Some amino acids are hydrophobic. What
does that mean?
It means the amino acids are repelled by
water.
Proteins
13. Briefly describe the four levels of protein organization.
Example: Spider silk Example: Hair
Example: Insulin
Example: Hemoglobin
Proteins
14. Proteins in our bodies operate efficiently at about
98.6 °F (37 °C), which is normal body temperature.
Study the graph below. What will happen to protein
function when a person has a very high fever, say
approaching 105 °F (41 °C)?
The weak interactions holding
proteins in their tertiary
structure will break down,
causing the protein to unravel
(denature) and lose function.
Proteins
15. Give a brief interpretation of this graph?
The graph shows that the optimal operating
pH for the enzyme pepsin is pH 2, and trypsin
around pH 8.
Proteins
16. Trypsin is an enzyme that breaks down proteins in
the small intestine. Pepsin also breaks down
proteins, however, based on its operating pH,
what organ of the body would you expect to find it?
Pepsin would most
likely be found in the
stomach, which has
strong acidic juices
with a low pH.
Proteins
17. List at least four functions of proteins?
Act as enzymes to speed up chemical reactions
Help transport substances across membranes
Store substances the organism needs
Help give the cell structure and movement
Provides protection against pathogens
Helps regulate metabolic processes
Proteins
18. List the functions of these common proteins?
Amylase:
An enzyme that breaks down
starches.
Hemoglobin:
A protein that carries oxygen
from the lungs to the body cells.
The main component in hair,
nails, and feathers.
Keratin:
Antibodies:
Protects the cell from pathogens.
Insulin:
A hormone that helps regulate
blood sugar levels.
Proteins
Here is an additional list of major digestive enzymes.
Proteins
19. Describe a simple test for detecting proteins in food.
a. Put blended samples of the food in a test
tube filled with blue Biuret’s reagent.
b. Place the test tube in a hot water bath for
3 minutes.
If protein is present, the blue
color will turn a purple color.
Proteins
20. Name some foods that are rich in proteins.
Tofu
Turkey
Fish
Cheese
Eggs
Lean Beef
Pork
Yogurt & milk
Beans
Nuts & seeds