Chapter 3.2.3 (Exam 1) Protein Structure

Question 1

What are oligopeptides/peptides?

Answer 1

Short polymers of 20 or fewer amino acids

Question 2

What are polypeptides?

Answer 2

Longer polymers, can be hundreds or even thousands of monomers combined

Question 3

How are amino acids bonded together?

Answer 3

Covalently in a condensation reaction by peptide linkages (peptide bonds)

Question 4

Which part of the amino acid chain is the beginning?

Answer 4

Called the N-terminus

The side with the amino group

Question 5

Which part of the amino acid chain is the end?

Answer 5

Called the C-terminus

The side with the carboxyl group

Question 6

Describe the primary structure of proteins.

Answer 6

Sequence of amino acids stabilized by peptide bonds

Question 7

What determines the 2D and 3D structure of proteins?

Answer 7

Properties of side chain functional groups determine how the protein can twist and fold

Question 8

Describe the secondary structure of proteins.

Answer 8

regular, repeated spatial patterns in different regions of the polypeptide stabilized by hydrogen bonds

Two of these structures are:
α helix
β pleated sheet

Question 9

Describe an α helix.

Answer 9

right-handed coil resulting from hydrogen bonding between N–H groups and C=O groups

Question 10

Describe a β pleated sheet.

Answer 10

two or more polypeptide chains are aligned; hydrogen bonds form between the chains

Can also form in a single polypeptide (polypeptide folds on itself)

Question 11

Describe the tertiary structure of proteins.

Answer 11

Folding results in the specific 3-D shape

Determined by interactions between R-groups (disulfide bonds, hydrogen bonds, hydrophobic interactions)

Question 12

How does the tertiary structure of proteins interact with other molecules?

Answer 12

The outer surfaces present functional groups that can interact with other molecules