BGM1002/L27 Lipid Metabolism

Question 1

Name 2 metabolic processes involving fats.

Answer 1

Lipolysis
Beta-oxidation

Question 2

How are fats stored in the body?

Answer 2

Triglycerides (triacylglycerol)

Question 3

Describe the structure of a typical triglyceride.

Answer 3

Glycerol backbone
3 fatty acid chains (sn-1-3)

Question 4

What kind of tissue stores fats?

Answer 4

White adipose tissue

Question 5

What function is brown adipose tissue linked to?

Answer 5

Thermal insulation

Question 6

Describe the structure of an adipocyte.

Answer 6

Large fat reservoir
Organelles all bunched up together

Question 7

Name the 2 types of fat stores.

Answer 7

Visceral fat
Subcutaneous fat

Question 8

How many calories are generated per gram of carbohydrate?

Answer 8

4

Question 9

How many calories are generated from 1g of proteins?

Answer 9

4

Question 10

How many calories are generated per gram of fat?

Answer 10

9

Question 11

Give 2 products of triglyceride oxidation.

Answer 11

Metabolic water
CO2

Question 12

Give 2 uses of fats in extreme environments.

Answer 12

Insulation
Buoyancy

Question 13

Name the 3 stages of lipid metabolism.

Answer 13

Lipolysis
Activation of fatty acids
Oxidation of fatty aids

Question 14

How is lipolysis mediated?

Answer 14

Hormone mediated
By glucagon, epinephrine

Question 15

Name the 3 main types of lipase enzymes.

Answer 15

Adipose triglyceride lipase (ATGL)
Hormone-sensitive lipase (HSL)
Monoglyceride lipase (MGL)

Question 16

What enzyme is involved in phosphorylation of glycerol?

Answer 16

Glycerol kinase

Question 17

What enzyme converts L-glycerol-3-phosphate to dihydroxyacetone phosphate?

Answer 17

Glycerol phosphate dehydrogenase

Question 18

How are fatty acids activated?

Answer 18

Addition of Coenzyme A to form acyl CoA

Question 19

How is energy provided for activation of fatty acids?

Answer 19

Coupling to hydrolysis of pyrophosphate

Question 20

How is the acyl group transported into the mitochondria?

Answer 20

As acyl-carnitine

Question 21

Where does beta-oxidation occur?

Answer 21

Mitochondrial matrix

Question 22

How many main steps make up beta-oxidation?

Answer 22

4

Question 23

What occurs in step 1 of beta oxidation?

Answer 23

Activated fatty acid is oxidised by FAD

Question 24

What enzyme is involved in step 1 of beta oxidation?

Answer 24

Acyl-CoA dehydrogenase

Question 25

What occurs in step 2 of beta oxidation?

Answer 25

Hydration brings in an oxygen

Question 26

What enzyme is involved in step 2 of beta oxidation?

Answer 26

Enoyl CoA hydratase

Question 27

What occurs in step 3 of beta oxidation?

Answer 27

Dehydrogenate oxidises beta carbon

Question 28

What enzyme is involved in step 3 of beta oxidation?

Answer 28

L-3-hydroxyacyl CoA dehydrogenase

Question 29

What other product is produced from step 3 of beta oxidation?

Answer 29

NADH2

Question 30

What occurs in step 4 of beta oxidation?

Answer 30

Cleavage or thiolysis

Question 31

What enzyme is involved in step 4 of beta oxidation?

Answer 31

3-ketoacyl thiolase

Question 32

What is the product of beta oxidation?

Answer 32

Acetyl CoA and 2CO2

Question 33

Give a brief overview of the 4 steps of beta oxidation.

Answer 33

1. Step FA oxidation by FAD 2. Hydration 3. Oxidation by dehydrogenase 4. Thiolysis

Question 34

How many molecules of ATP are yielded from one molecule of palmitate?

Answer 34

108 ATP 0.42 ATP per Dalton

Question 35

Where are ketone bodies mainly produced?

Answer 35

Liver

Question 36

What organs can use ketones as an energy source?

Answer 36

Brain and heart

Question 37

In what disease are there high levels of ketones in the blood?

Answer 37

Type 1 diabetes

Question 38

What is the key molecule in the committed step of fatty acid synthesis?

Answer 38

Malonyl CoA

Question 39

Give 2 allosteric modulators for fatty acid synthesis via aceyl CoA carboxylase.

Answer 39

Citrate Palmitoyl CoA

Question 40

What occurs as a result of insulin resistance in type 2 diabetes?

Answer 40

Non Alcohol Fatty Liver Disease (NAFLD)

Question 41

Where does fatty acid synthesis occur?

Answer 41

Cytoplasm

Question 42

What is the activating carrier in fatty acid synthesis?

Answer 42

Acyl carrier protein

Question 43

What is the electron carrier in fatty acid synthesis?

Answer 43

NADPH from pentose phosphate pathway

Question 44

What is the 2C unit in fatty acid synthesis?

Answer 44

Donated from malonyl CoA (3C)

Question 45

Where does fatty acid degradation occur?

Answer 45

Mostly mitochondrial matrix

Question 46

What is the activating carrier in fatty acid degradation?

Answer 46

CoA

Question 47

What is the electron carrier in fatty acid degradation?

Answer 47

NAD+/FAD

Question 48

What is the 2C unit in fatty acid degradation?

Answer 48

Leaves as acetyl CoA (2C)

Question 49

Name the 4 main steps of fatty acid synthesis.

Answer 49

Condensation Reduction Dehydration Reduction

Question 50

Name the key enzyme controlling fatty acid synthesis.

Answer 50

Acetyl CoA carboxylase