Proteins 2.2

Question 1

Properties and functions of collagen?

Answer 1

FIBROUS
- provides mechanical strength
-found in artery walls, tendons, cartilage

Question 2

Properties and function of Keratin?

Answer 2

FIBROUS
-Rich in cysteine (lots of disulfide links - very strong)
-impermeable barrier to infection and is hard + waterproof
-E.g nails, claws, hair

Question 3

Properties and function of Elastin?

Answer 3

FIBROUS
-cross linking and coiling makes it very stong
-stretch + recoil
-E.g in skin, blood vessels (maintain blood pressure)

Question 4

Properties and function of Haemoglobin?

Answer 4

GLOBULAR
-conjugated protein
-contains 4 prosthetic haem groups
-haem group contains an iron ion
-carry O2 from lungs to tissues

Question 5

Structure and function of Insulin?

Answer 5

GLOBULAR
-hydrophillic amino acids associate on outside of the molecule > This makes it soluble in water
-binds to glycoprotein receptors on muscle and fat cells to increase their uptake of glucose from blood

Question 6

Structure and function of pepsin?

Answer 6

GLOBULAR
-digests protein in the stomach
-Has many acidic R groups to survive in acidic conditions in stomach

Question 7

Fibrous proteins

Answer 7

regular, repetitive sequences of amino acids
Usually insoluble in water
Form fibres which tend to have structural function.

Question 8

Globular Proteins

Answer 8

Tend to be spherical
Hydrophillic groups exposed on outside makes it soluble in water