Honor Bio 7.1

Question 1

What are the similarities in the structure of all amino acids?

Answer 1

All amino acids have a central carbon atom (alpha carbon), an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a unique R group (side chain).

Question 2

What are the differences in the structure of amino acids?

Answer 2

Different R groups.

Question 3

What defines the primary structure of a protein?

Answer 3

The sequence of amino acids in a polypeptide chain.

Question 4

What is the secondary structure of a protein?

Answer 4

Folding into alpha-helices and beta-sheets stabilized by hydrogen bonds.

Question 5

What characterizes the tertiary structure of a protein?

Answer 5

The 3D shape of a single polypeptide chain formed by interactions between side chains (R groups).

Question 6

What is quaternary structure?

Answer 6

The arrangement of multiple polypeptide chains into a functional protein complex.

Question 7

What happens during protein denaturation?

Answer 7

A protein loses its secondary, tertiary, and quaternary structure due to external stress (e.g., heat, pH changes), causing it to lose its function.

Question 8

How do hydrophobic interactions contribute to tertiary structure?

Answer 8

Hydrophobic side chains cluster together in the interior of the protein, avoiding water.

Question 9

How do hydrophilic interactions contribute to tertiary structure?

Answer 9

Hydrophilic side chains are exposed on the protein surface, interacting with water.

Question 10

How do acidic and basic side chains interact in tertiary structure?

Answer 10

Acidic (-COO⁻) and basic (-NH₃⁺) side chains form ionic bonds, stabilizing the structure.

Question 11

How do cysteine side chains contribute to tertiary structure?

Answer 11

Cysteine side chains form disulfide bonds (S-S), providing strong covalent links.

Question 12

What is the role of enzymes in proteins?

Answer 12

Enzymes catalyze chemical reactions by lowering activation energy.

Question 13

What is the function of structural proteins like collagen?

Answer 13

Provide support and shape to cells and tissues.

Question 14

How do transport proteins like hemoglobin function?

Answer 14

Carry substances (e.g., oxygen) through the body.

Question 15

What role do antibodies play as proteins?

Answer 15

They are involved in immune defense, recognizing and neutralizing pathogens.

Question 16

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

Answer 16

Substituting a hydrophobic amino acid with a hydrophilic one can disrupt the protein’s tertiary structure by altering hydrophobic interactions, potentially causing misfolding and loss of function.

Question 17

How are the effects of protein denaturation different from the effects of a mutation?

Answer 17

Denaturation: Temporary loss of function due to structural changes; the primary structure remains intact.
Mutation: Permanent change in the amino acid sequence, potentially altering protein folding, structure, and function.