Biochemistry of the liver - Week 6

Question 1

What are the principal roles of the liver?

Answer 1

First destination of most nutrients & xenobiotics
Bile production
Elimination of unwanted molecules
Secretion of plasma proteins
Storage of fuels, iron and vitamins

Question 2

What change in stool may be present in end-stage liver disease?

Answer 2

Change to be very pale

Question 3

What are the main plasma proteins found in blood?

Answer 3

Albumin
alpha globulins
beta globulins
gamma globulins

Question 4

Immunoglobulins are which kind of globulins?

Answer 4

Gamma globulins

Question 5

What are the main functions of plasma proteins?

Answer 5

Maintenance of osmotic pressure
Transport of hydrophpbic substances
pH buffering
Enzymatic
Immunity

Question 6

What is the role of albumin?

Answer 6

transport of hydrophobic substances

Question 7

Give 2 examples of beta globulins.

Answer 7

Transferrin & Fibrinogen

Question 8

What is the role of transferrin?

Answer 8

Transports Fe3+

Question 9

What is the most abundant plasma protein?

Answer 9

Albumin

Question 10

Which factors may result in reduced albumin levels?

Answer 10

Liver disease or starvation/low protein diet

Question 11

Albumin is used to transport hydrophobic proteins such as…

Answer 11

fatty acids, bilirubin, thyroid hormones

Question 12

Albumin is important in the transport of exogenous substances such as…

Answer 12

Aspirin

Question 13

Iron is an essential component of…

Answer 13

haemoglobin, myoglobin and cytochromes

Question 14

Iron is transported as…

Answer 14

Ferric ion (Fe3+)

Question 15

Are thyroid hormones hydrophobic or hydrophillic?

Answer 15

Hydrophobic

Question 16

How is thyroxine transported?

Answer 16

thyroid-binding globulin

Question 17

How is cortisol transported?

Answer 17

cortisol-binding globulin

Question 18

How is Copper transported in the blood?

Answer 18

bound to ceruloplasmin

Question 19

Lipoproteins are synthesised by…

Answer 19

The liver

Question 20

Name the lipoproteins in increasing density.

Answer 20

Chylomicrons, VLDL, IDL, LDL, HDL

Question 21

What is the function of LDLs?

Answer 21

Cholesterol transport to peripheral tissues

Question 22

What is the function of HDLs?

Answer 22

Reverse cholesterol transport

Question 23

Which molecule carries out reverse cholesterol transport?

Answer 23

HDL

Question 24

How is excess cholesterol removed from the body?

Answer 24

Excreted as bile salts in faeces

Question 25

Which vitamins are stored in the liver?

Answer 25

A, D and B12

Question 26

Iron comes from the breakdown of…

Answer 26

Haemoglobin

Question 27

Cholesterol is a precursor of…

Answer 27

Bile acids, steroid hormones and Vitamin D

Question 28

What happens to the majority of cholesterol?

Answer 28

esterified to a wide range of long-chain fatty acids

Question 29

What is the main regulating enzyme in cholesterol synthesis?

Answer 29

HMG-CoA Reductase

Question 30

How many carbons does Cholesterol have?

Answer 30

27C

Question 31

HMG-CoA Reductase is the target for…

Answer 31

Statins

Question 32

Which factors inhibit HMG-CoA Reductase?

Answer 32

Dietary cholesterol and high intrahepatocyte cholesterol

Question 33

Cholesterol is used to synthesise which Vitamin?

Answer 33

D3

Question 34

Which steroid hormones are synthesised using cholesterol?

Answer 34

Corticosteroids, androgens, oestrogens

Question 35

What is the role of anion exchange resins?

Answer 35

bind bile salts and inhibit reabsorption in the enterohepatic circulation

Question 36

What is the main role of Cytochrome P450?

Answer 36

function to metabolize potentially toxic compounds, including drugs and products of endogenous metabolism such as bilirubin, principally in the liver.