3.3 Study Guide

Question 1

What are the similarities in amino acid structure?

Answer 1

They all have the same basic structure. In the middle of each amino acid is a carbon called the a carbon, and attached are four groups - a hydrogen, an a- carboxyl group, an a-amine group, and an R-group.

Question 2

What are the differences in amino acid structure?

Answer 2

The R group (side chains) for each of the amino acids will differ in structure, electrical charge, and polarity.

Question 3

What are the four levels of protein structure?

Answer 3

• Primary (1 degree) Structure.
• Secondary (2 degree) Structure.
• Tertiary (3 degree) Structure.
• Quaternary (4 degree) Structure.

Question 4

Please explain what happens during protein denaturation.

Answer 4

The secondary and tertiary structures get destroyed and only the primary structure is retained. Covalent bonds are broken and interaction between amino-acid chains gets disrupted.

Question 5

Please explain how tertiary structure is formed by interactions between hydrophobic interactions.

Answer 5

Amino acids with nonpolar, hydrophobic R groups cluster together on the inside of the protein, leaving hydrophilic amino acids on the outside to interact with surrounding water molecules.

Question 6

Please explain how tertiary structure is formed by interactions between hydrophilic interactions.

Answer 6

Generally stabilized by outside polar hydrophilic, hydrogen, and ionic bond interaction, and internal hydrophobic interactions between nonpolar amino side chains.

Question 7

Please explain how tertiary structure is formed by interactions between cysteine side chains.

Answer 7

Disulfide bonds, covalent linkages between the sulfur-containing side chains cysteines, are much stronger than the other types of bonds that contribute to tertiary structure. They act like molecular “safety pins,” keeping parts of the polypeptide firmly attached to one another.

Question 7

Please explain how tertiary structure is formed by interactions between acidic and basic side chains.

Question 8

Why and how would the structure and function of a protein change if a hydrophobic amino acid was substituted for a hydrophilic one?

Answer 8

They would change because their non attraction to water would change, meaning they would become attracted to water. This could possibly inactivate the protein. This could also lead to unfolding, which could destroy the function.

Question 9

What are the eight functions of proteins?

Answer 9

1. Storage.
2. Movement.
3. Transport.
4. Identification.
5. Defense.
6. Chemical Reactions.
7. Structure.
8. Communication.

Question 10

What are the functions of proteins involved in?

Answer 10

Almost everything.

Question 11

How many different amino acids (monomers) does the structure of protein have?

Answer 11

20.

Question 12

What element does protein have?

Answer 12

Carboxyl.