Proteins Review

1. Proteins Review

2. This structure represents a polymer. Proteins 1. What are the individual units called? They are called monomers

3. 2. What does poly mean? Poly means ‘many’ and polymer means ‘many pieces.’ Proteins 3. What does mono mean? Mono means ‘one’ and monomer means ‘one piece.’

4. This structure represents a protein. Proteins 4. What kind of molecule makes up its monomers? The amino acid

5. This structure represents a protein. Proteins 5. What are the bonds that link the amino acid monomers called? The bonds are peptide linkages

6. This structure represents a protein. Proteins 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

7. This structure represents a protein. Proteins 7. What molecule is released when an amino acid is added to the polypeptide? (Click once to see animation) A water molecule is released

8. This structure represents a protein. Proteins 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

9. 9. How many different kinds of amino acids are common to living things? Proteins There are twenty different kinds

10. 10. Draw the basic amino acid structure and label its functional groups. Proteins O N C C R Carboxyl group Amino group H H H H Variable group

11. 11. Some amino acids are hydrophilic. What does that mean? Proteins 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.

12. 13. Briefly describe the four levels of protein organization. Proteins Example: Spider silk Example: Hair Example: Insulin Example: Hemoglobin

13. 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)? Proteins The weak interactions holding proteins in their tertiary structure will break down, causing the protein to unravel (denature) and lose function.

14. 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

15. 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? Proteins Pepsin would most likely be found in the stomach, which has strong acidic juices with a low pH.

16. 17. List at least four functions of proteins? 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

17. 18. List the functions of these common proteins? An enzyme that breaks down starches. Amylase: Proteins 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.

18. Here is an additional list of major digestive enzymes. Proteins

19. 19. Describe a simple test for detecting proteins in food. Put blended samples of the food in a test tube filled with blue Biuret’s reagent. Place the test tube in a hot water bath for 3 minutes. Proteins If protein is present, the blue color will turn a purple color.

20. 20. Name some foods that are rich in proteins. Turkey Tofu Proteins Fish Cheese Lean Beef Eggs Yogurt & milk Pork Nuts & seeds Beans