Types of proteins

Question 1

Globular proteins properties

Answer 1

• compact
• roughly spherical
• water soluble (non-polar/hydrophobic R groups folded on the inside of the protein with polar/hydrophilic R groups on the outside)

Question 2

What structures do globular proteins contain?

Answer 2

tertiary or quaternary

Question 3

Example of globular protein

Answer 3

Insulin@:
- soluble so can be transported in the bloodstream
- specific structures to bind to specific receptors on target cell-surfaces

Question 4

Conjugated proteins

Answer 4

Type of globular protein that contains a
prosthetic group (proteins without prosthetic groups are called simple proteins)

Question 5

Examples of conjugated proteins

Answer 5

Haemoglobin:
- quaternary protein (x2 alpha x2 beta)
- haem prosthetic group x4

Catalase:
- quaternary protein
- haem prosthetic group x4
- Fe2+ ions interact with H2O2

Question 6

Fibrous proteins properties

Answer 6

• long (repetitive primary structure)
• water insoluble (high proportion of non-polar/hydrophobic R groups)

Question 7

What structures do fibrous proteins contain?

Answer 7

primary or secondary

Question 8

Examples of fibrous proteins

Answer 8

• keratin (skin, hair, nails)
• elastin (blood vessels, alveoli)
• collagen (connective tissue in skin, tendons, ligaments and nervous system)