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MEH > Energy Production In Lipids > Flashcards

Energy Production In Lipids Flashcards

1
Q

True or false: lipids are hydrophilic

A

False - they’re hydrophobic

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2
Q

Are lipids soluble in water?

A

No

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3
Q

True or False: Lipids are more reduced than carbohydrates

A

True. This means they release more energy when oxidised

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4
Q

True or false: complete oxidation of lipids requires more oxygen than carbohydrates

A

True - lipids are more reduced than carbohydrates

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5
Q

Give 3 examples of fatty acids derivatives

A
  1. fatty acids
  2. Triacylglycerols
  3. Phospholipids
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6
Q

Give 3 examples of Hydroxy-methyl-glutaric acid derivatives

A
  1. Ketone bodies
  2. Cholesterol
  3. Bile acids and salts
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7
Q

Give 4 examples of lipid soluble vitamins

A

A, D, E and K

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8
Q

What are fatty acids stored as

A

Triacylglycerols

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9
Q

Where do you get lipid soluble vitamins from

A

Diet

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10
Q

What are triacylglycerols made up of

A

3 carbon glycerol backbone and 3 fatty acid side chains

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11
Q

What process produces triacylglycerols

A

Esterification

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12
Q

What process breaks down triacylglycerols

A

Lipolysis

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13
Q

Are triacylglycerols hydrophobic or hydrophilic

A

Hydrophobic

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14
Q

Where are triacylglycerols stored

A

Adipose tissue

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15
Q

How are triacylglycerols stored?

A

In an anhydrous form of lipid droplets

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16
Q

What hormone mobilises fat

A

Glucagon

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17
Q

What hormone causes the storage of fat

A

Insulin

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18
Q

What are chylomicrons

A

Lipoprotein particles that transport triglycerides in the blood via the lymphatics to adipose tissue

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19
Q

What hydrolyses lipids in the pancreas

A

Pancreatic lipases

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20
Q

How are fatty acids transported from storage in adipose tissue to consumer tissue

A

Albumin fatty acids complexes

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21
Q

What happens to fatty acids in consumer tissues

A

Oxidised to produce energy

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22
Q

In which cells does metabolism of fatty acids not occur

A
  1. RBC as they have no mitochondria

2. Brain as fatty acids cant pass through the blood brain barrier

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23
Q

What does a low glucose level do to fatty acids stores in adipose tissue

A

Releases it to be used as an alternative fuel

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24
Q

What does it mean if fats are saturated and unsaturated

A
  • saturated = no double bonds

- unsaturated = one or more double bonds

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25
Q

What does amphipathic mean

A

Contains both hydrophobic and hydrophilic groups

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26
Q

Why are some polyunsaturated fatty acids essential

A

Mammals cant make a double bond beyond carbon 9

27
Q

Where does fatty acid metabolism occur

A

Mitochondria

28
Q

How are fatty acids activated in their metabolism

A

By linking them to coenzyme A outside the mitochondria

29
Q

What transports the activated fatty acids across the inner mitochondrial membrane

A

Carnitine shuttle

30
Q

What enzyme activates fatty acids

A

Fatty acyl CoA synthase

31
Q

True or false: activated fatty acids can cross the inner mitochondrial membrane readily

A

False - this is why they require the carintine shuttle transporter

32
Q

Is ATP needed for fatty acid activation

A

Yes

33
Q

What is the activated fatty acid called

A

Fatty acylCoA

34
Q

Why can the activated fatty acid complex cross the outer mitochondrial membrane but not the inner one

A

The inner mitochondrial membrane is impermeable

35
Q

How does the carnitine shuttle transport work

A

The activated fatty acid complex exchanges the CoA for carnitine using the enzyme carnitine acyltransferase. This complex can then pass through the transport via facilitated diffusion and then returns back to the CoA complex once inside

36
Q

What enzyme is used in the carnitine shuttle transport

A

Carnitine acyltransferase

37
Q

What is the carnitine shuttle transporter inhibited by

A

Malonyl CoA

38
Q

What can defects in the carnitine shuttle transporter cause

A

Exercise Intolerance and lipid droplets in muscle

39
Q

What happens to the fatty acid CoA complex once it enters the intermitochondrial space

A

The fatty acid goes through a series of oxidation steps with 2 carbons removed in each cycle

40
Q

What is the end product of beta-oxidation

A

Acetyl CoA

41
Q

Does beta-oxidation occur in the absence of oxygen

A

No

42
Q

How many moles of atp are produced in the beta oxidation pathway

A

None

43
Q

Where is glycerol metabolised

A

Liver

44
Q

Outline glycerol metabolism

A
  • Glycerol is converted into glycerol phosphate using atp
  • glycerol phosphate is then either used in triacylglycerol synthesis or produces dihydroxyacetone phosphate which can be used in glycolysis.
45
Q

What enzyme is used to convert glycerol into glycerol phosphate

A

Glycerol kinase

46
Q

What is CoA derived from

A

B vitamins

47
Q

Where are ketone bodies produced

A

Liver

48
Q

Give 3 examples of ketone bodies

A
  1. Acetoacetate
  2. Acetone
  3. Beta- hydroxybutyrate
49
Q

How is acetone produced

A

Spontaneous (non-enzymatic) decarboxylation of acetoacetate

50
Q

What is normal plasma ketone levels

A

Less than 1 mM

51
Q

Outline the production of ketone bodies

A

Acetyl CoA is converted into Hydroxymethy glutaryl-CoA by synthase which then is converted into ketone bodies by lyase

52
Q

What enzyme converts acetyl CoA into Hydroxymethy glutaryl-CoA

A

Synthase

53
Q

What enzyme converts Hydroxymethy glutaryl-CoA into ketone bodies

A

Lyase

54
Q

What do statin drugs do

A

Inhibits the production of cholesterol by inhibiting the action of HMG-CoA reductase

55
Q

When is acetyl CoA used to make ketone bodies instead of entering the Kreb’s cycle

A

Beta oxidation causes high NADH production which inhibits the enzymes in the Kreb’s cycle meaning acetyl CoA cant enter the Kreb’s cycle

56
Q

How are ketone bodies metabolised

A

They are oxidised to reform acetyl CoA when then enters the Kreb’s cycle

57
Q

What determines whether ketone bodies or cholesterol will be produced from hydroxymethyl glutaryl CoA

A
  • in high insulin lyase is inhibited so cholesterol is produced
  • in high glucagon (starvation) reductase is inhibited so keton bodies are produced
58
Q

What enzymes are used to produce cholesterol

A

HMG reductase

59
Q

What does the production of ketone bodies in starvation do to the glucose

A

Spares it so that it is only used by the brain (conserves glucose)

60
Q

What is ketogenesis

A

The production of ketone bodies from fatty acids

61
Q

What happens in prolonged starvation

A

Protein is broken down to amino acids which is converted in to Pyruvate in the liver and then into glucose by gluconeogensis

62
Q

What is it called when the ketone leave is above the threshold and excreted in urine

A

Ketonuria

63
Q

What is ketoacidosis

A

A build up of ketone bodies in the blood as they are acidic

64
Q

How might volatile acetone be excreted

A

In the lung and so you can smell it on their breath

MEH (22 decks)

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