Proteins

Question 1

Describe the formation of a peptide bond

Answer 1

Carboxylic acid condenses with amino group with release of water

Question 2

What is primary structure?

Answer 2

Amino acid sequence

Question 3

What is secondary structure?

Answer 3

Alpha helix or beta pleated sheets

Question 4

What is tertiary structure?

Answer 4

3D structure formed by assembly of secondary structure

Question 5

What is quaternary structure?

Answer 5

Structure formed by more than one polypeptide chains

Question 6

What are the 2 types of proteins?

Answer 6

Fibrous and globular

Question 7

What is are some examples of fibrous proteins?

Answer 7

Keratin and collagen

Question 8

Where is keratin found?

Answer 8

Hair and nails

Question 9

Where is collagen found?

Answer 9

Skin

Question 10

What are some examples of globular proteins?

Answer 10

Pepsin, insulin and haemoglobin

Question 11

Where is pepsin found and its function?

Answer 11

• enzyme in stomach
• digests proteins

Question 12

Where is insulin produced and its function?

Answer 12

• prancreas
• regulates glucose in blood

Question 13

Where is haemoglobin found and its function?

Answer 13

• red protein pigment in red blood cell
• transports oxygen in blood

Question 14

What is haemoglobin comprised of?

Answer 14

4 subunits each containing iron atom bound to haem group

Question 15

What are the properties of fibrous proteins?

Answer 15

• no tertiary structure
• long fibres or sheets in shape
• insoluble in water
• length of polypeptide chain may vary
• structural functions

Question 16

What are the properties of globular proteins?

Answer 16

• tertiary structure and sometimes quaternary
• spherical shape
• soluble in water
• length of polypeptide chain is always identical
• metabolic functions