Proteins

Question 1

Primary sequence?

Answer 1

Sequence of amino acids in a polypeptide

Question 2

Secondary structure?

Answer 2

Spatial arrangement of R groups that are near each other in a sequence

Question 3

What are the types of secondary structure?

Answer 3

• Alpha helices
• Beta sheets
• Turns

Question 4

How are alpha helices stabilised?

Answer 4

H bonds between NH and CO groups in the next “spin” of the helix

Question 5

What stabilises beta sheets?

Answer 5

H bonds between amide groups of sheets running parallel

Question 6

Tertiary structure?

Answer 6

Interactions between R groups that are far away from each other in the sequence

Question 7

What stabilises tertiary structure?

Answer 7

• Van der waals
• Ionic
• H bonds
• Disulphide bridges
• Hydrophobic interactions

Question 8

What residue forms disulphide bridges?

Answer 8

Two cysteine residues

Question 9

Where can disulphide bridges form?

Answer 9

• Intermolecularly

- Between two different polypeptides

Question 10

Quaternary structures?

Answer 10

• Spatial arrangement of polypeptide chains in multi chain proteins

Question 11

What structure remains in tact after denaturation?

Answer 11

Primary

Question 12

What does denaturation effect?

Answer 12

• Reduces solubility
• Loses biological activity
• Easier to digest

Question 13

What is glycosylation?

Answer 13

Post translational modification where a sugar is added via an amino acid

Question 14

What is one example of a glycoprotein?

Answer 14

Immunoglobulins

Question 15

Where does glycolysation occur in the cell?

Answer 15

• ER

- Golgi

Question 16

Function of lipoproteins?

Answer 16

Transport through the blood

Question 17

What do lipoproteins transport in the blood?

Answer 17

• Water
• Fat
• Cholesterol

Question 18

What are metalloproteins?

Answer 18

• Protein with a bound metal ion

Question 19

Function of metalloproteins?

Answer 19

• Enzymes
• Signalling
• Transport

Question 20

What is co-operative binding using haemoglobin as an example

Answer 20

• O2 binds to one subunit

- Conformational change in other subunits increases their affinity for O2

Question 21

What causes sickle cell anaemia?

Answer 21

HYDROPHILIC glutamic acid substituted by HYDROPHOBIC Valine

Question 22

What is the structure of collagen?

Answer 22

Coiled polypeptides in a helix structure

Question 23

What is scurvy caused by?

Answer 23

Vitamin C deficiency

Question 24

What does a vitamin C deficiency cause?

Answer 24

Formation of weaker collagen

Question 25

Effects of osteogenesis imperfecta?

Answer 25

• Collagen can’t form the tight coil

- Secondary and tertiary structure lost so brittle collagen produced

Question 26

What happens if a mutation causes no LDL receptors to reach the cell membrane?

Answer 26

• No receptors

- LDL not released

Question 27

What disease can result from the LDL receptor mutation?

Answer 27

Familial hypercholesterolemia

Question 28

What does FH result in?

Answer 28

Early CVD