Proteins

Question 1

What are globular proteins

Answer 1

They are round and compact.

The hydrophilic R groups on amino acids are pushed outside the molecule, so they tend to be soluble and easily transported.

Reactive.

Question 2

What are fibrous proteins

Answer 2

Tough and rope shaped.

Insoluble and strong.

They’re structural and unreactive.

Question 3

Haemoglobin

Answer 3

It’s a globular protein that carries oxygen around in red blood cells.

It is a conjugated protein so it’s a protein with a non-protein group attached.

It has a prosthetic group, which is the non-protein part. This is called haem, which contains iron that oxygen binds to.

Four polypeptide chains.

Question 4

Insulin

Answer 4

Globular protein.

Two polypeptide chains held by disulfide bonds.

Question 5

Amylase

Answer 5

Globular protein.

Catalyses starch.

Single amino acid chain with both alpha helix and beta pleated sheets.

Question 6

Collagen

Answer 6

FIBROUS

Animal connective tissues, like bone.

Strong.

Minerals can bind to increase its rigidity.

Question 7

Keratin

Answer 7

FIBROUS

Found in external structures, such as hair and nails.

Flexible or hard and tough.

Question 8

Elastin

Answer 8

FIBROUS

Elastic connective tissue, such as skin or ligaments.

Can return to original shape.