Chapter 4: Protein 3D structure (Test 1)

Question 1

Polypeptides are linked by?

Answer 1

• Peptide/amide bonds

Question 2

What are disulfide bonds?

Answer 2

• The oxidation of two cysteines to make a cystine

Question 3

Which configuration are peptide bonds in to minimize steric clashes?

Answer 3

• Trans config

Question 4

What are the types of secondary structures?

Answer 4

• α-helix

- β-sheets

Question 5

Which bonds stabilize β-sheets ?

Answer 5

• Hydrogen bonds

Question 6

What are supersecondary structures?

Answer 6

• The combination of α-helices and β-sheets

Question 7

What is keratin?

Answer 7

• A structural protein found in wool and hair

- A member of coiled-coil proteins

Question 8

What is collagen?

Answer 8

• A structural protein found in skin, bone, tendons, cartilage, and teeth
• Consist of 3 intertwined helical chains
• Glycine appears every third residue
• Stabilized by the steric repulsion in proline

Question 9

What is osteogenesis imperfecta?

Answer 9

• Brittle bone disease

- Mutation from the substitution of another amino acid in place of glycine

Question 10

What are globular proteins?

Answer 10

• e.g. myoglobin
• form complicated 3D structures
• exterior consists of charged and polar amino acids

Question 11

What are the forces found in tertiary structures?

Answer 11

• Noncovalent interactions

- Covalent interactions

Question 12

What are the ways to denature a proteins?

Answer 12

• Heat
• pH
• Detergents
• Urea
• Guanidine hydrochloride

Question 13

What are intrinsically unstructured proteins (IUPs)?

Answer 13

• They do not have a defined structure under physiological conditions until they interact with other molecules

Question 14

What are chaperones?

Answer 14

• Aid in the correct and timely folding of proteins