Proteins Review

ProteinsThis structure represents a polymer.

1. What are the individual units called?

They are called monomers

Proteins2. What does poly mean?

3. What does mono mean?Mono means ‘one’ and monomer means ‘one piece.’

Poly means ‘many’ and polymer means ‘many pieces.’

Proteins

4. What kind of molecule makes up its monomers?

The amino acid

This structure represents a protein.

ProteinsThis structure represents a protein.

5. What are the bonds that link the amino acid monomers called?

The bonds are peptide linkages

ProteinsThis 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

ProteinsThis structure represents a protein.

7. What molecule is released when an amino acid is added to the polypeptide?

A water molecule is released

(Click once to see animation)

ProteinsThis structure represents a protein.

8. What molecule must be added in order to remove an amino acid from the polypeptide?

A water molecule is added

(Click once to see animation)

Proteins9. How many different kinds of amino acids are common to living things?

There are twenty different kinds

Proteins10. Draw the basic amino acid structure and label its functional groups.

C

HHC

H H

O

R

N Carboxyl group

Amino group

Variable group

Proteins11. Some amino acids are hydrophilic. What does that mean?

12. Some amino acids are hydrophobic. What does that mean?

It means the amino acids are attracted to water.

It means the amino acids are repelled by water.

Proteins13. Briefly describe the four levels of protein organization.

Example: Hair Example: Spider silk

Example: Insulin Example: Hemoglobin

Proteins14. 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.

Proteins15. 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.

Proteins16. 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

Act as enzymes to speed up chemical reactions

17. List at least four functions of proteins?

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

Proteins18. List the functions of these common proteins?

Amylase:

Hemoglobin:

Keratin:

An enzyme that breaks down starches.

A protein that carries oxygen from the lungs to the body cells.The main component in hair, nails, and feathers.

Antibodies: Protects the cell from pathogens.

Insulin: A hormone that helps regulate blood sugar levels.

ProteinsHere is an additional list of major digestive enzymes.

Proteins19. 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.

Proteins20. Name some foods that are rich in proteins.

Cheese

Turkey

Fish

Pork

Lean Beef

Tofu

Beans

Eggs

Yogurt & milk

Nuts & seeds