Lipid Synthesis And Degredation

Question 1

What is the definition of a lipid?

Answer 1

Macromolecules soluble in non-polar solvents

Question 2

Give some examples of lipids

Answer 2

Fatty acids
Glycolipids
Glycerolphospholipids
Sphingolipids
Triglycerides
Cholesterol

Question 3

When are fats synthesised and stored?

Answer 3

When our calorific intake exceeds the immediate needs of the body

Question 4

How does the energy content of fat per gram compare to carbs and protein?

Answer 4

1g fat= 37kj
1g protein = 17kj
1g carbs = 16kj

Question 5

What percentage of the energy from the British diet is fat?

Answer 5

40%

Question 6

How much did obesity rise in adults from 1993->2014?

Answer 6

14.9%->25.6%

Question 7

What BMI is classified as obese?

Answer 7

30Kg/M^2

Question 8

What are fats most often made from?

Answer 8

Dietary carbs

Question 9

What is the preferred energy source for cardiac muscle?

Answer 9

Fats

Question 10

What is the preferred energy source for the brain?

Answer 10

Glucose

Question 11

Where and how are fats stored?

Answer 11

In adipose tissue as triglycerides

Question 12

Give the features of fatty acids

Answer 12

Chains of methyl groups
Terminal carboxylic acid
Double bonds (if present) are usually in cis conformation
No double bonds in less than position nine

Question 13

What happens to the citrate when the amount of ATP is high and the need for glucose is low?

Answer 13

Citrate is transported out of the mitochondria

Question 14

What happens to the citrate when its outside the mitochondria?

Answer 14

Converted back to acetyl coA and then synthesised into fatty acids

Question 15

What happens to the fatty acids once made?

Answer 15

They will either stay in the liver or transported into the bloodstream

Question 16

Where is cholesterol transported to?

Answer 16

Non-hepatic tissue

Question 17

What does fatty acid synthesis require?

Answer 17

Acetyl coA
NADPH
ATP

Question 18

What does the citrate-malate antiPorter do?

Answer 18

Transfer of the acetyl coA to the cytosol

Question 19

What are the starting and ending molecules in the citrate-maleate antiPorter?

Answer 19

Acetyl coA- oxaloacetate

Question 20

How is the NADPH provided for the citrate- malate antiPorter?

Answer 20

By the pentose phosphate pathway

Question 21

What is the first step in fatty acid synthesis activated by?

Answer 21

Citrate

Question 22

What is the first step in fatty acid synthesis inhibited by?

Answer 22

Palmatic acid

Question 23

What does the first step in fatty acid synthesis require?

Answer 23

The vitamin biotin

Question 24

What is fatty acid synthase responsible for?

Answer 24

Fatty acid synthesis

Question 25

What are the intermediates in fatty acid synthase covalently linked to?

Answer 25

6 acyl carrier protein

Question 26

What does fatty acid synthase enable?

Answer 26

The efficient and rapid movement of the growing fatty acid chain to be passed from one active site to the next

Question 27

What are the three steps in fatty acid degradation

Answer 27

Mobilisation (adipocytes) Activation (liver cytosol) Degradation (liver mitochondria)

Question 28

What hormones stimulate the mobilisation of fatty acids?

Answer 28

Glucagon | Adrenaline

Question 29

What are fatty acids activated by in the liver cytoplasm

Answer 29

Acyl CoA synthase

Question 30

What does fatty acid coA react with to from fatty acyl carnitine?

Answer 30

The alcohol carnitine

Question 31

Where is the long chain FA activated?

Answer 31

On the outer mitochondrial membrane

Question 32

What can carnitine deficiency cause?

Answer 32

Muscle weakness or death

Question 33

What is fatty acid transport inhibited by?

Answer 33

Malonyl coA

Question 34

What is the result of fatty acid/ beta oxidation?

Answer 34

FADH2, NADH and acetyl coA

Question 35

Where does fatty acid/ beta oxidation occur?

Answer 35

In the liver mitochondria

Question 36

What are the sequence of steps in fatty acid/ beta oxidation?

Answer 36

Oxidation Hydration Oxidation Thiolysis

Question 37

In non-hepatic tissue how many ATPs does complete oxidation of palmitate yield?

Answer 37

106

Question 38

Why does ketogenesis happen?

Answer 38

Fasting, uncontrolled diabetes, prolonged exercise

Question 39

What happens in ketogenesis?

Answer 39

Stimulates fatty acid breakdown producing acetyl coA

Question 40

Where does the metabolism shift towards in ketogenesis?

Answer 40

Maintain blood glucose

Question 41

What does the loss of oxaloacetic acid do?

Answer 41

Limits energy production from acetyl coA

Question 42

What is excess acetyl coA used for?

Answer 42

To form ketone bodies

Question 43

What are ketone bodies made up of?

Answer 43

Acetoacetate, 3 betahydroxybutyrate and acetone

Question 44

Where are ketone bodies used?

Answer 44

Cardiac muscle and renal cortex and by the brain (only during starvation)

Question 45

What does the breakdown of triglycerides give?

Answer 45

Acetyl coA and glycerol

Question 46

What is glycerol used for in the liver?

Answer 46

The synthesis of glucose by gluconeogenesis

Question 47

What is glycerol used for in the muscle?

Answer 47

In glycolysis and oxidative phosphorylation to produce ATP

Question 48

What does insulin increase?

Answer 48

Glycolysis in the liver Fatty acid synthesis in the liver Triglyceride in adipose tissue

Question 49

What does insulin decrease?

Answer 49

Beta oxidation

Question 50

What do glucagon and adrenaline increase?

Answer 50

Triglyceride mobilisation