2: Biochemistry of the liver

Question 1

What are some functions of the liver?

Answer 1

First pass metabolism

Bile production

Detoxification

Secretion of plasma proteins

Storage

Question 2

What is stored in the liver?

Answer 2

Glycogen (fuel)

Metal ions (iron and copper)

Vitamins

Question 3

What is produced by amino acid metabolism in the liver?

Answer 3

Urea

Question 4

Which test separates proteins based on their size and charge?

Answer 4

Electrophoresis

Question 5

Which protein, produced by the liver, is a marker of liver function?

Answer 5

Albumin

Question 6

Alpha and beta globulins are released by the ___ and act as transport molecules.

Answer 6

liver

Question 7

Name the alpha globulin responsible for transporting copper.

Answer 7

Caeruloplasmin

Question 8

Name the alpha globulin responsible for transporting Vitamin A.

Answer 8

Retinol binding protein

Question 9

Which beta globulin transports iron?

Answer 9

Transferrin

Question 10

Which protein acts as an indicator of iron deficiency?

Answer 10

Transferrin

Question 11

What inactive form of a blood clotting agent is produced by the liver?

What is the active agent called?

Which type of globulin is it?

Answer 11

Fibrinogen

Fibrin

Beta

Question 12

What is the most abundant plasma protein found in the blood?

Answer 12

Albumin

Question 13

Albumin is small, water-soluble and (positively / negatively) charged.

Answer 13

negatively charged

Question 14

Why may a patient’s albumin levels be low?

Answer 14

Liver disease

Malnutrition (specifically not enough protein)

Question 15

What does albumin transport?

Answer 15

Fatty acids

Bilirubin

Thyroid hormones

Question 16

What antiplatelet drug is transported in the blood by albumin?

Answer 16

Aspirin

Question 17

What is an essential component of haemoglobin, myoglobin and cytochromes?

Answer 17

Iron

Question 18

Which plasma protein transports iron ions?

What form are the iron ions in?

What type of globulin is this plasma protein?

Answer 18

Transferrin

Fe³⁺

Beta globulin

Question 19

What is the storage form of iron in cells?

Answer 19

Ferritin

Question 20

Which plasma protein transports copper in the blood?

What type of globulin is this plasma protein?

Answer 20

Caeruloplasmin

Alpha globulin

Question 21

What is Wilson’s disease?

Answer 21

Deficiency of ceruloplasmin causing copper deposition in liver, brain

Question 22

Steroid hormones are (hydrophilic / hydrophobic).

Answer 22

hydrophobic

Question 23

Can hydrophobic molecules travel in the blood?

Answer 23

No - they require a carrier

Question 24

Can hydrophilic molecules travel in the blood?

Answer 24

Ye

Question 25

Name two hormones which bind to carrier globulins to travel in the blood.

Answer 25

**Thyroxine** **Cortisol**

Question 26

**Carrier globulins** increase the ___ \_\_\_ of hormones, allowing them to work for longer.

Answer 26

**half life**

Question 27

Which type of molecule **transports fat between organs and tissues**?

Answer 27

**Lipoproteins**

Question 28

Name some **lipoproteins** from **least dense** to **most dense**.

Answer 28

**Chylomicrons** **VLDL IDL** **LDL HDL**

Question 29

What does a **chylomicron** do?

Answer 29

**Transports dietary fat to the liver**

Question 30

What does **LDL** do?

Answer 30

**Transports cholesterol from the liver to peripheral tissues**

Question 31

What does **HDL** do?

Answer 31

**Transports cholesterol from peripheral tissues to the liver** i.e the opposite of LDL, making HDL the "good one" and LDL the "bad one"

Question 32

What is the **"bad"** lipoprotein associated with atherosclerosis?

Answer 32

**LDL**

Question 33

What is the **"good"** lipoprotein associated with reversing the action of LDL?

Answer 33

**HDL**

Question 34

What is the only organ which can metabolise and excrete cholesterol?

Answer 34

**Liver**

Question 35

HDL collects cholesterol and transports it back to the liver. In what form can it then be excreted?

Answer 35

**Bile salts** remember that the liver breaks down cholesterol to make into bile salts, and bile salts are usually then recycled into cholesterol

Question 36

**Cholesterol** is an essential component of which part of animal cells?

Answer 36

**Cell membrane**

Question 37

Cholesterol provides ___ for the cell membrane.

Answer 37

**stability**

Question 38

What are two pathologies associated with major **cholesterol** involvement?

Answer 38

**Cardiovascular disease** (atherosclerosis, LDL) **Gall stones** (crystallised cholesterol)

Question 39

**Cholesterol** is a precursor for...

Answer 39

**bile salts** **steroid hormones** **Vitamin D**

Question 40

Can all cells synthesise **cholesterol**?

Answer 40

**Yes**

Question 41

What is the main site of cholesterol synthesis?

Answer 41

**Liver**

Question 42

Synthesis of cholesterol is very energy (**light / intensive**).

Answer 42

**energy-intensive**

Question 43

What is the **rate-limiting enzyme** for cholesterol synthesis?

Answer 43

**HMG-CoA reductase**

Question 44

Which class of drugs **inhibit** HMG-CoA reductase to lower cholesterol levels?

Answer 44

**Statins**

Question 45

What vitamin, derived from **cholesterol**, is involved in calcium and phosphorus metabolism?

Answer 45

**Vitamin D**

Question 46

Name three types of **steroid hormone** derived from cholesterol.

Answer 46

**Corticosteroids** **Androgens** **Oestrogens**

Question 47

What is the main product of cholesterol metabolism?

Answer 47

**Bile salts**

Question 48

By what process are bile salts reabsorbed by the liver?

Answer 48

**Enterohepatic recycling**

Question 49

Which class of drug is used to block bile salt absorption in the terminal ileum, lowering cholesterol levels?

Answer 49

**Bile salt sequestrants**