Lipid Oxidation Flashcards Preview

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Flashcards in Lipid Oxidation Deck (50):
1

what does gall bladder do

emulsify fat into little lipid drolplets to make them more accesible to lipases which break them down into individual FA's and reincorporated into triglycerides and put into a chilomicron

2

Where do chilomicrons tracel

blood vessels and lymph to deliver FA's through lipo protein lipase which is activiated by insulin which helps break down FA's and allow them to be absorbed. Glycerol goes back into bloodstream to be reabsorbed. through

3

What is B-48

protein component of chylomicron recognized by lipoprotein lipase.

4

What are the major classes of human plasma lipoproteins

1. chylomicrons
2. VLDL
3. LDL
4. HDL

5

Which two lipoproteins have the highest amount of triacylglycerols

1. Chylomicrons; dietary lipid
2. VLDL; lipid from liver

6

What is ApoB-100

What LDL receptors bind to and bring it in; if you have a mutation in LDL receptor you get problems with cardiovascular system

7

What is LCAT

enzyme that HDL uses this when it scavengers cholesterol from bloodstream.

8

What activates LCAT

Apo A

9

What are the apolipoproteins

1. Apo A
2. Apo B-100: Ligand for receptor
3. Apo B-48: structural role
4. Apo C-II; Activator of lipoprotein lipase
5. Apo E: ligand for receptor

10

What are the principal enzymes in lipoprotein metabolism

1. LCAT
2. Lipoprotein lipase (LPL
3. Hepatic lipase
4. acid lipase
5. MTP

11

What activates uptake of fat from chylomicrons

lipoprotein lipase

12

What are healthy levels LDL and HDL

LDL: 40 mg/dL mdn
>50 mg/dL women

13

WHat are healthy cholesterol levels

<200

14

What is healthy level of triglycerides

<100-150

15

Where are lipoprotein lipases found

found on endothelial cell surface, mostly around adipose, heart and skeletal muscle

16

what activates lipoprotein lipase

insulin

17

Glycerol remains in bloodstream and is ____to liver for _____

recycled; gluconeogenesis

18

What hormone is released when we're fasting to release free fatty acids and glycerol

Hormone sensitive lipase

19

what are perilipins

keep lipid droplet in adipocyte in tact and prevent release of triglyceride prematurely.

20

What does hormone sensitive lipase do

cleave off individual FA from triglyceride and release it into the bloodstream

21

What are two targets of protein kinase A

perilipins and hormone sensitve lipase

22

Describe fatty acid activation

1. convert FA to acyl coA derivatives using Acyl CoA synthetase

23

Conversion of FA to an activated acyl derivative requires ____high energy phosphate bonds

2

24

FA must be activated to ____in order to be transported into the mitochondria to initiate ____

FACoA; beta oxidation

25

What is carnitine

Derived from lysine; carrier for lipids; transports fatty acyl-CoA into mitochondria for oxidation

26

What happens when you have carnitine deficiency? What if you have too much of it?

hypoketotic hypoglycemia-cant oxidize fat so losing out on production of energy;
too much results in conversion to TMAO by gut flora which promotes atherosclerosis

27

What does carnitine acyltransferase 1 do

Swap CoA carrier to carnitine carrier--> fatty acyl carnitine transfers fatty acyl carnitine in and free carnitine back out.

28

What does carnitine acyltransferase II do

Converts FA from carnitine back to fatty acyl CoA

29

What does malonylCoA inhibit

CAT 1 which prevents futile cycle of FA breakdown and synthesis happening simultaneously

30

What is the first stage of fatty acid oxidation

1. Beta oxidation: NADH and FADH2 made go to electron transport chain. Acetyl CoA go to TCA cycle

31

What happens during beta oxidation

1. Dehydrogenation: Make a keto group on beta carbon by converting single bond to DB by degydrogenation. H's then get donated to FAD to make FADH2 to go into electron transport chain.
2. Hydrate DB to make hydroxyl group by using NAD to make NADH to go to ETC
3. Cleave by thialase to reduce the length of chain to make new fatty acyl CoA and released an acetyl CoA which goes to TCA cycle

32

How many cycles does it take for beta oxidation

7

33

what is the yield for palmitate

8 Acetyl CoA
7 NADH
7 FADH2

34

How many ATPs can you make from oxidation of fat

129

35

What is the deficiency in medium chain Acyl CoA dehydrogenase

Most common defect in fat metabolism; genetic disorder in infants causes fasting hypoglycemia. Dont have energy from fat being produced.

36

Most FA contain ___DB, but in oxidation we produce____DB. Unsaturated fatty acids cause decrease in ATP produced because you have to use energy to move DB around to change its configuration.

cis; trans

37

Oxidation of odd-chain FA can produce what?

Only release acetyl CoA and 3 carbon compound -1 Propionyl CoA which can be converted to succinyl CoA which goes into TCA cycle to form oxaloacetate. This can form glucose!

38

Rate limiting step of FA oxidation

Transport of fats into mitochondria

39

What are the steps of FA synthesis

1. High blood glucose activates insulin
2. Phosphatase removes phosphate groups on acetyl CoA carboxylase and activates it.
3. Low blood glucose activates glucagon which activates protein kinase A which phosphorolates acetyl CoA carboxylase and inactivate it.

40

What can block CAT 1

malonyl CoA; so we cant hook FA to carnitine carrier to get it into mitochondria

41

Fatty acid oxidation occurs in all tissues except ___ and ____

brain and erythrocytes

42

Where does FA oxidation occur

mitochondrial matrix

43

What does FA oxidation require

acetyl CoA, FAD, and NAD+

44

What is FA oxidation inhibited by

malonyl CoA

45

When does FA occur

low energy state (high ADP) and during fasting. (high glucagon)

46

Where does FA synthesis occur

in liver and adipose in cytosol

47

What is required for FA synthesis

Acetyl CoA, NADPH, malonyl CoA

48

What activates FA synthesis

citrate

49

What is FA synthesis inhibited by

long chain acyl CoA

50

When does FA synthesis occur

high energy state. Lots of ATP present; Usually after carbohydrate feeding. (high insulin)