Session 2-Energy Production:Lipids

Question 1

True or false: lipids are generally soluble in water

Answer 1

FALSE - insoluble

Question 2

Lipids are more reduced than carbs. What are the consequences of this?

Answer 2

Lipids release more energy when oxidised

Question 3

What are the three classes of lipids?

Answer 3

1) Fatty acid (FA) derivatives
2) Hydroxy-methyl-glutaric (HMG) acid derivatives
3) Vitamins

Question 4

Which vitamins are lipid molecules?

Answer 4

A, D, E and K

Question 5

Which fatty acid derivatives do we need to know?

Answer 5

Fatty acids

Triacylglycerols (triglycerides)

Question 6

What are FA stored as?

Answer 6

Triacylglycerols

Question 7

Which HMG acid derivative do we need to know?

Answer 7

Ketone bodies (C4)

Question 8

What are ketone bodies?

Answer 8

Water soluble fuel molecules-alternative substrate when glucose is low, solubilise energy in fat

Question 9

Which process produces triacylglycerols (TAG)?

Answer 9

Esterification

Question 10

True or false: triacylglycerols (TAG) are hydrophilic

Answer 10

FALSE - hydrophobic

Question 11

How are triacylglycerols (TAG) stored within cells?

Answer 11

Lipid droplets

Question 12

When are TAGs utilised?

Answer 12

Prolonged exercise
‘Starvation’
During pregnancy

Question 13

How is the storage/mobilisation of TAGs controlled by hormones?

Answer 13

Glucagon mobilises fat

Insulin puts fat into store

Question 14

What are chylomicrons?

Answer 14

Lipoproteins formed to package FA and allow them to be transported in the blood

Question 15

Which enzyme catalyses the breakdown of lipids in the small intestine?

Answer 15

Pancreatic lipase

Question 16

How are FA carried to tissues?

Answer 16

Albumin-FA complex

Question 17

Complete the sentence:

FA can be saturated, ___________ or _____________

Answer 17

Unsaturated

Amphipathic

Question 18

Why are some polyunsaturated FA essential?

Answer 18

Because mammals cannot introduce a double bond beyond C9

Question 19

Where does triacylglycerol metabolism occur?

Answer 19

GI tract, extracellular

Question 20

Where does FA metabolism occur?

Answer 20

Mitochondria

Question 21

What activates FA outside the mitochondrion?

Answer 21

Linking to coenzyme A by the action of fatty acyl CoA synthase

Question 22

How are FA transported across the inner mitochondrial membrane?

Answer 22

Carnitine shuttle

Question 23

How many carbons are removed with each cycle of FA catabolism?

Answer 23

2

Question 24

What inhibits the transport of fatty acyl-CoA across the mitochondrial membrane?

Answer 24

Malonyl-CoA

Question 25

What is another term for FA catabolism?

Answer 25

Beta-oxidation

Question 26

How many ATP molecules are produced from C6 FA?

Answer 26

41

Question 27

Why doesn't FA metabolism occur in the brain?

Answer 27

FA cannot pass through the blood/brain barrier

Question 28

Why doesn't FA metabolism occur in RBCs?

Answer 28

No mitochondria

Question 29

Where is glycerol metabolised?

Answer 29

Liver

Question 30

What is the main convergence point for catabolic pathways?

Answer 30

Acetyl CoA

Question 31

Which vitamin does CoA contain?

Answer 31

B5

Question 32

Which atom links CH3CO group to coenzyme A?

Answer 32

S-atom

Question 33

True or false: ketone bodies are more hydrophilic than lipid

Answer 33

TRUE

Question 34

Which three ketone bodies are produced in the body?

Answer 34

1) Acetoacetate 2) Acetone 3) beta-hydroxybutyrate

Question 35

True or false: acetone is produced by the spontaneous decarboxylation of acetoacetate

Answer 35

TRUE

Question 36

What is the normal plasma ketone body concentration?

Answer 36

<1mM

Question 37

What is the plasma ketone body concentration in untreated type 1 diabetes?

Answer 37

>10mM

Question 38

What synthesises ketone bodies?

Answer 38

Liver mitochondria

Question 39

What ensures that acetyl-CoA doesn't enter the TCA cycle and instead forms ketone bodies?

Answer 39

NADH-high energy signal which inhibits the enzymes in the TCA cycle so acetyl-CoA doesn't enter the TCA cycle

Question 40

Complete the sentence: When the insulin/glucagon ratio is high (ie fed state), _______ is inhibited, _____________ is activated and this leads to the synthesis of cholesterol

Answer 40

Lyase | Reductase

Question 41

Complete the sentence: When the insulin/glucagon ratio is low (ie starvation, diabetes), ______ is activated, ___________ is inhibited, leading to the synthesis of ________ _________

Answer 41

Lyase Reductase Ketone bodies

Question 42

What is ketonuria?

Answer 42

Excretion of large amounts of ketone bodies in the urine

Question 43

What can ketonuria be a test for?

Answer 43

Diabetes

Question 44

Volatile acetone may be excreted via which organ?

Answer 44

Lungs