BGM1002/L27 Lipid Metabolism Flashcards

1
Q

Name 2 metabolic processes involving fats.

A

Lipolysis
Beta-oxidation

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2
Q

How are fats stored in the body?

A

Triglycerides (triacylglycerol)

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3
Q

Describe the structure of a typical triglyceride.

A

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

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4
Q

What kind of tissue stores fats?

A

White adipose tissue

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5
Q

What function is brown adipose tissue linked to?

A

Thermal insulation

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6
Q

Describe the structure of an adipocyte.

A

Large fat reservoir
Organelles all bunched up together

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7
Q

Name the 2 types of fat stores.

A

Visceral fat
Subcutaneous fat

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8
Q

How many calories are generated per gram of carbohydrate?

A

4

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9
Q

How many calories are generated from 1g of proteins?

A

4

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10
Q

How many calories are generated per gram of fat?

A

9

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11
Q

Give 2 products of triglyceride oxidation.

A

Metabolic water
CO2

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12
Q

Give 2 uses of fats in extreme environments.

A

Insulation
Buoyancy

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13
Q

Name the 3 stages of lipid metabolism.

A

Lipolysis
Activation of fatty acids
Oxidation of fatty aids

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14
Q

How is lipolysis mediated?

A

Hormone mediated
By glucagon, epinephrine

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15
Q

Name the 3 main types of lipase enzymes.

A

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

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16
Q

What enzyme is involved in phosphorylation of glycerol?

A

Glycerol kinase

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17
Q

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

A

Glycerol phosphate dehydrogenase

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18
Q

How are fatty acids activated?

A

Addition of Coenzyme A to form acyl CoA

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19
Q

How is energy provided for activation of fatty acids?

A

Coupling to hydrolysis of pyrophosphate

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20
Q

How is the acyl group transported into the mitochondria?

A

As acyl-carnitine

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21
Q

Where does beta-oxidation occur?

A

Mitochondrial matrix

22
Q

How many main steps make up beta-oxidation?

A

4

23
Q

What occurs in step 1 of beta oxidation?

A

Activated fatty acid is oxidised by FAD

24
Q

What enzyme is involved in step 1 of beta oxidation?

A

Acyl-CoA dehydrogenase

25
Q

What occurs in step 2 of beta oxidation?

A

Hydration brings in an oxygen

26
Q

What enzyme is involved in step 2 of beta oxidation?

A

Enoyl CoA hydratase

27
Q

What occurs in step 3 of beta oxidation?

A

Dehydrogenate oxidises beta carbon

28
Q

What enzyme is involved in step 3 of beta oxidation?

A

L-3-hydroxyacyl CoA dehydrogenase

29
Q

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

A

NADH2

30
Q

What occurs in step 4 of beta oxidation?

A

Cleavage or thiolysis

31
Q

What enzyme is involved in step 4 of beta oxidation?

A

3-ketoacyl thiolase

32
Q

What is the product of beta oxidation?

A

Acetyl CoA and 2CO2

33
Q

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

A
  1. Step FA oxidation by FAD
  2. Hydration
  3. Oxidation by dehydrogenase
  4. Thiolysis
34
Q

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

A

108 ATP
0.42 ATP per Dalton

35
Q

Where are ketone bodies mainly produced?

A

Liver

36
Q

What organs can use ketones as an energy source?

A

Brain and heart

37
Q

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

A

Type 1 diabetes

38
Q

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

A

Malonyl CoA

39
Q

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

A

Citrate
Palmitoyl CoA

40
Q

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

A

Non Alcohol Fatty Liver Disease (NAFLD)

41
Q

Where does fatty acid synthesis occur?

A

Cytoplasm

42
Q

What is the activating carrier in fatty acid synthesis?

A

Acyl carrier protein

43
Q

What is the electron carrier in fatty acid synthesis?

A

NADPH from pentose phosphate pathway

44
Q

What is the 2C unit in fatty acid synthesis?

A

Donated from malonyl CoA (3C)

45
Q

Where does fatty acid degradation occur?

A

Mostly mitochondrial matrix

46
Q

What is the activating carrier in fatty acid degradation?

A

CoA

47
Q

What is the electron carrier in fatty acid degradation?

A

NAD+/FAD

48
Q

What is the 2C unit in fatty acid degradation?

A

Leaves as acetyl CoA (2C)

49
Q

Name the 4 main steps of fatty acid synthesis.

A

Condensation
Reduction
Dehydration
Reduction

50
Q

Name the key enzyme controlling fatty acid synthesis.

A

Acetyl CoA carboxylase