2.3.4 Globular & Fibrous Proteins

Question 1

Describe the structure of globular proteins.

Answer 1

1. compact
2. roughly spherical
3. soluble in water

Question 2

Why do globular proteins have spherical shapes?

Answer 2

1. non-polar hydrophobic R groups are orientated towards the center
2. polar hydrophilic are oriented away from the center

Question 3

Why globular proteins are soluble?

Answer 3

Water molecules can surround the polar hydrophilic R groups

Question 4

List some functions of globular proteins

Answer 4

1. transport proteins (hemoglobin)- because of its solubility
2. enzymes and immunoglobins - specific shapes

Question 5

Describe the structure of fibrous proteins

Answer 5

• long strands of polypeptide chains that have cross linkages dure to hydrogen bonds
• little or no tertiary structure

Question 6

Why fibrous proteins are insoluble

Answer 6

Due to the large number of hydrophobic R groups

Question 7

What makes fibrous proteins suitable to be in nails and keratin?

Answer 7

1. highly repetitive sequence of amino acids making it strong
2. insolubility