Biology Section____ Name_____________________________________
Dr. Wexler
Protein Structure Quiz 2
Date_______

1. The two types of protein secondary structure are:

A.

B.

2. Draw a molecular model of a dipeptide, including all atoms and covalent bonds. Represent the side chains as R1 and R2. Circle the peptide bond.

3. What two levels of protein structure are lacking in fibrous proteins such as keratin?

A.

B.

4. Draw a model of a fibrous protein:

5. List two ways in which a protein can be denatured (ie. its structure altered):

A.

B.

6. Globular proteins such as casein (the major protein in milk) are roughly spherical in shape and soluble in water. Fibrous proteins such as keratin are elongated and insoluble.

A. Which type of protein is found in fingernails? How do you know?

B. Which type of protein is found in serum (the liquid portion of blood)? How do you know?

7. Scleroderma is a severe condition characterized in part by a thickening and hardening of the skin. The uncontrolled deposition of which type of protein results in this symptom?

A. Globular protein

B. Fibrous protein

8. In the Lock-and-Key model of enzyme action, the part of the enzyme that recognizes the substrate is known as the

A. enzyme-substrate complex
B. product
C. enzyme-product complex
D. active site

9. Which of the following will increase the rate of an enzyme-catalyzed reaction?
A. Lowering the temperature to 0°C
B. Raising the temperature to 70°C
C. Adding alcohol
D. Adding more substrate

10. Compare the activation energy needed in the presence or absence of enzyme in enzyme-mediated reactions.

11. Illustrate your answer to question 10 using an energy diagram.