Homework Questions
PROTEINS (p. 40 – 48)
1. a. What is the function of the genetic information in DNA?
b. Why are proteins so important? What two major roles do proteins fulfill?
2. a. In terms of structure, what is a protein?
b. Define conformation.
3. a. Draw and label an amino acid using Figure 28.
b. Amino acids have different properties based on their R group or side chain. List the different groups.
c. What functional group is found in the side chain of an acidic amino acid? A basic amino acid?
4. a. What type of reaction joins amino acids?
b. Sketch the reaction that joins alanine and methionine. Label the bond formed with its bond name and functional group linkage name and show all the products.
5. Define i) polypeptide ii) amino/N terminus iii) carboxyl terminus
6. Refer back to 2b and the 2 major roles of proteins. How is the shape of structural proteins different from that of globular proteins?
7. Define and give a simple sketch of primary, secondary, tertiary and quaternary structure of a protein.
8. Briefly describe the beta-pleated sheet of silk and the alpha-helix of keratin. What benefit do these structures provide for the protein?
9. Tertiary structure begins to take shape as the R groups interact with water. Which two groups are important in this and how do they affect the protein’s shape?
10. As the protein folds and the R groups get closer to one another, the final tertiary shape of the polypeptide chain is maintained by four different types of chemical interactions between the side chains. List and briefly describe four interactions involved in protein folding and the conformation of the protein.
11. True or False:
a. The final shape of a polypeptide (tertiary structure) is dependent on primary structure.
b. The final shape of a polypeptide is dependent on chemical factors like the pH of the surroundings.
c. The final shape of a polypeptide is dependent on physical factors like the temperature.
12. a. What is denaturation?
b. What does denaturation mean for the role of a protein?
13. How does denaturation occur?
14. Is denaturation permanent?
15. Give some examples of how protein denaturation can be both dangerous and useful.