Glycogen, Lysosomes, FA, Lipids Flashcards Preview

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Flashcards in Glycogen, Lysosomes, FA, Lipids Deck (67)
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31

Describe the process of FA synthesis...location, shuttle, enzymes, cofactors

Citrate from Mt matrix leaves via the citrate shuttle to the cell cytoplasm to make Acetyl-CoA via ATP citrate lyase =>
Biotin & CO2 are added to make Malonyl-CoA =>
FA synthesis is now done w/ Palmitate (16C FA)

32

Describe the process of FA degradation...location, shuttle, enzymes, cofactors. What will block this pathway?

FA & CoA via FA-CoA synthetase makes Acyl-CoA =>
Acyl-CoA will go from cytoplasm through the carnitine shuttle unchanged into the Mt matrix =>
Acyl-CoA is then Beta-oxidized (broken down into acetyl-CoA groups) =>
Ketone bodies are formed & TCA can start

Malonyl-CoA can block Acyl-CoA from entering carnitine shuttle & trapping it in cytoplasm

33

Where are FA & AA metabolized and into what?

in liver, they are metabolized into acetoacetate & Beta-hydroxybutyrate (to be used in muscle & brain)

34

What can cause the production of ketone bodies? How?

prolonged starvation & DKA cause OAA to deplete for gluconeogenesis;
Alcoholism has excess NADH so OAA is shunted to malate;

Both cause buildup of Acetyl-CoA so glucose & FFA production is halted & ketone bodies are produced

35

How will a person undergoing ketone production present? What will not be present?

Breath smells fruity due to acetone

Urine test for ketones does NOT detect Beta-hydroxybutyrate

36

What are the metabolic processes after a meal (fed state)?

Glycolysis & aerobic respiration;

Insulin stimulates storage of lipids, proteins, glycogen

37

What are the metabolic processes between meals (fasting)?

hepatic glycogenolysis (major);
hepatic gluconeogenesis, adipose release of FFA (minor)

Glucagon, Epi stimulate use of fuel reserves

38

In the starvation state of 1-3 days, how is blood glucose maintained?

Hepatic glycogenolysis;
Adipose release of FFA;
muscle & liver which shift fuel use from glucose to FFA;
hepatic gluconeogenesis from peripheral tissue lactate & alanine & from adipose tissue glycerol & propionyl-CoA

39

What is the only triacylglycerol component that contributes to gluconeogenesis?

propionyl-CoA (from odd chain FFA)

40

During starvation, how long does it take glycogen reserves to be depleted?

1 day

41

Starvation after 3 days leads to what source of energy being used? What is key for this source?

Adipose stores are used & ketones are primary source for brain;
Once depleted, protein degradation accelerates leading to organ failure & death (amount of stores determine survival)

42

What is the rate limiting step in cholesterol synthesis? How does it work? what induced it?

HMG-CoA reductase (induced by insulin) converts HMG-CoA to mevalonate

43

A majority of plasma cholesterol is esterified by what?

Lecithin-cholesterol acyltransferase (LCAT)

44

What is the MOA of statins?

competitively & reversible inhibit HMG-CoA reductase

45

role of Pancreatic lipase

degradation of dietary triglycerides (TG) in small intestine.

46

role of lipoprotein lipase

degradation of TG circulating in chylomicrons and VLDLs. Found on vascular endothelial surface

47

role of Hepatic TG lipase (HL)

degradation of TG remaining in IDL.

48

role of hormone sensitive lipase

degradation of TG stored in adipocytes.

49

role of Cholesterol ester transfer protein (CETP)—

mediates transfer of cholesterol esters to other
lipoprotein particles (VLDL, IDL, LDL

50

What are the major apolipoproteins? function?

E => mediates remnant uptake
A-1 => activates LCAT
C-2=> lipoprotein lipase cofactor
B-48 => mediates chylomicron secretion
B-100=> binds LDL receptor

51

What apolipoproteins function with chylomicron?

E
A-1
C-2
B-48

52

What apolipoproteins function with chylomicron remnant?

E
B-48

53

What apolipoproteins function with VLDL?

E
C-2
B-100

54

What apolipoproteins function with IDL?

E
B-100

55

What apolipoproteins function with LDL?

B-100

56

What apolipoproteins function with HDL?

E
A-1
C-2

57

What are lipoproteins made of? What are the primary carriers of cholesterol?

cholesterol, TGs, phospholipids;

LDL transports cholesterol from liver to tissues;
HDL transports cholesterol from periphery to liver

58

What is the role of the chylomicron?

Delivers dietary TGs to peripheral tissue;
Delivers cholesterol to liver in the form of chylomicron remnants, which are mostly depleted of their triacylglycerols;
Secreted by intestinal epithelial cells.

59

What is the role of VLDL?

Delivers hepatic TGs to peripheral tissue.
Secreted by liver.

60

What is the role of IDL?

Formed in the degradation of VLDL;
Delivers TGs and cholesterol to liver.