Energy Production In Lipids

Question 1

True or false: lipids are hydrophilic

Answer 1

False - they’re hydrophobic

Question 2

Are lipids soluble in water?

Answer 2

No

Question 3

True or False: Lipids are more reduced than carbohydrates

Answer 3

True. This means they release more energy when oxidised

Question 4

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

Answer 4

True - lipids are more reduced than carbohydrates

Question 5

Give 3 examples of fatty acids derivatives

Answer 5

1. fatty acids
2. Triacylglycerols
3. Phospholipids

Question 6

Give 3 examples of Hydroxy-methyl-glutaric acid derivatives

Answer 6

1. Ketone bodies
2. Cholesterol
3. Bile acids and salts

Question 7

Give 4 examples of lipid soluble vitamins

Answer 7

A, D, E and K

Question 8

What are fatty acids stored as

Answer 8

Triacylglycerols

Question 9

Where do you get lipid soluble vitamins from

Answer 9

Diet

Question 10

What are triacylglycerols made up of

Answer 10

3 carbon glycerol backbone and 3 fatty acid side chains

Question 11

What process produces triacylglycerols

Answer 11

Esterification

Question 12

What process breaks down triacylglycerols

Answer 12

Lipolysis

Question 13

Are triacylglycerols hydrophobic or hydrophilic

Answer 13

Hydrophobic

Question 14

Where are triacylglycerols stored

Answer 14

Adipose tissue

Question 15

How are triacylglycerols stored?

Answer 15

In an anhydrous form of lipid droplets

Question 16

What hormone mobilises fat

Answer 16

Glucagon

Question 17

What hormone causes the storage of fat

Answer 17

Insulin

Question 18

What are chylomicrons

Answer 18

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

Question 19

What hydrolyses lipids in the pancreas

Answer 19

Pancreatic lipases

Question 20

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

Answer 20

Albumin fatty acids complexes

Question 21

What happens to fatty acids in consumer tissues

Answer 21

Oxidised to produce energy

Question 22

In which cells does metabolism of fatty acids not occur

Answer 22

1. RBC as they have no mitochondria

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

Question 23

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

Answer 23

Releases it to be used as an alternative fuel

Question 24

What does it mean if fats are saturated and unsaturated

Answer 24

• saturated = no double bonds

- unsaturated = one or more double bonds

Question 25

What does amphipathic mean

Answer 25

Contains both hydrophobic and hydrophilic groups

Question 26

Why are some polyunsaturated fatty acids essential

Answer 26

Mammals cant make a double bond beyond carbon 9

Question 27

Where does fatty acid metabolism occur

Answer 27

Mitochondria

Question 28

How are fatty acids activated in their metabolism

Answer 28

By linking them to coenzyme A outside the mitochondria

Question 29

What transports the activated fatty acids across the inner mitochondrial membrane

Answer 29

Carnitine shuttle

Question 30

What enzyme activates fatty acids

Answer 30

Fatty acyl CoA synthase

Question 31

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

Answer 31

False - this is why they require the carintine shuttle transporter

Question 32

Is ATP needed for fatty acid activation

Answer 32

Yes

Question 33

What is the activated fatty acid called

Answer 33

Fatty acylCoA

Question 34

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

Answer 34

The inner mitochondrial membrane is impermeable

Question 35

How does the carnitine shuttle transport work

Answer 35

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

Question 36

What enzyme is used in the carnitine shuttle transport

Answer 36

Carnitine acyltransferase

Question 37

What is the carnitine shuttle transporter inhibited by

Answer 37

Malonyl CoA

Question 38

What can defects in the carnitine shuttle transporter cause

Answer 38

Exercise Intolerance and lipid droplets in muscle

Question 39

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

Answer 39

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

Question 40

What is the end product of beta-oxidation

Answer 40

Acetyl CoA

Question 41

Does beta-oxidation occur in the absence of oxygen

Answer 41

No

Question 42

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

Answer 42

None

Question 43

Where is glycerol metabolised

Answer 43

Liver

Question 44

Outline glycerol metabolism

Answer 44

- 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.

Question 45

What enzyme is used to convert glycerol into glycerol phosphate

Answer 45

Glycerol kinase

Question 46

What is CoA derived from

Answer 46

B vitamins

Question 47

Where are ketone bodies produced

Answer 47

Liver

Question 48

Give 3 examples of ketone bodies

Answer 48

1. Acetoacetate 2. Acetone 3. Beta- hydroxybutyrate

Question 49

How is acetone produced

Answer 49

Spontaneous (non-enzymatic) decarboxylation of acetoacetate

Question 50

What is normal plasma ketone levels

Answer 50

Less than 1 mM

Question 51

Outline the production of ketone bodies

Answer 51

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

Question 52

What enzyme converts acetyl CoA into Hydroxymethy glutaryl-CoA

Answer 52

Synthase

Question 53

What enzyme converts Hydroxymethy glutaryl-CoA into ketone bodies

Answer 53

Lyase

Question 54

What do statin drugs do

Answer 54

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

Question 55

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

Answer 55

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

Question 56

How are ketone bodies metabolised

Answer 56

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

Question 57

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

Answer 57

- in high insulin lyase is inhibited so cholesterol is produced - in high glucagon (starvation) reductase is inhibited so keton bodies are produced

Question 58

What enzymes are used to produce cholesterol

Answer 58

HMG reductase

Question 59

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

Answer 59

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

Question 60

What is ketogenesis

Answer 60

The production of ketone bodies from fatty acids

Question 61

What happens in prolonged starvation

Answer 61

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

Question 62

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

Answer 62

Ketonuria

Question 63

What is ketoacidosis

Answer 63

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

Question 64

How might volatile acetone be excreted

Answer 64

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