Chapter 4: Protein Structure And Function

Question 1

Primary structure

Answer 1

Amino Acids
Condensation reaction
In specific sequence
Covalent bonds only

Question 2

Secondary structure

Answer 2

Stable polypeptide folding

Alpha helix: carbonyl group + amino group 4 aa away

Betta sheets: Angled at each carbon, creating pleated sheet. Can be anti parallel or parallel

Question 3

Tertiary structure

Answer 3

3D conformation

Structures are not coiled and not random

Domains: Folded functional area of protein

Question 4

Quaternary structure

Answer 4

Two or more polypeptide chains

Each polypeptide is a subunit

Question 5

Disulfide bonds

Answer 5

They form cross-links between different regions of polypeptide chains

Helps stabilize protein structure

Question 6

Describe when alpha helices will partition into a membrane. What type of amino acids must be present?

Answer 6

The hydrophilic polypeptide backbone (stabilized H bonding) is shielded from the hydrophobic lipid hydrocarbons.
Nonpolar amino acids must be present in order to make it through the environment of the hydrophobic tails of the phospholipids