Lipid Uptake and Synthesis Flashcards Preview

IUSM Biochemistry > Lipid Uptake and Synthesis > Flashcards

Flashcards in Lipid Uptake and Synthesis Deck (48)
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1
Q

What does pancreatic lipase do?

A

Breaks apart triacylglycerol into 2 fatty acids and monoacylglycerol

2
Q

What drug is a reversible inhibitor of pancreatic lipase?

A

Orlistat (OTC = xenical, alli)

3
Q

What is a common side effect of pancreatic lipase inhibitory drugs? ir orlistat, xenical, alli, …

A

Unable to absorb fat soluble vitamins like A, D, E, and K

4
Q

What are the main two functions of Cholestyramine?

A

Removes bile acids, which stimulates liver bile acid synthesis from cholesterol.
Stimulates LDL receptor in liver causing reduced serum cholesterol

5
Q

Secretion of pancreatic enzymes occurs in response to what gut hormone?

A

cholecystokinin

6
Q

What is the primary function of bile salts?

A

To aide in digestion by forming micelles to package long and very long chain fatty acids

7
Q

What are the 5 major lipoproteins that enable fats and cholesterol to move within the water-based bloodstream?

A

chylomicrons, IDL, HDL, VLDL, LDL

8
Q

Where are chylomicrons produced?

A

Intestinal epithelia

from dietary fat

9
Q

Where are VLDLs produced?

A

In liver mainly from dietary CHO

10
Q

Where are IDLs produced?

A

In the blood after Triacylglycerol digestion

VLDL remnant

11
Q

Where are LDLs produced?

A

In the blood after triacylglycerol digestion
Remnant of IDL
End product of VLDL

12
Q

Where are HDLs produced?

A

Liver and Intestine

13
Q

What are the two major functions of HDLs?

A

Exchanges proteins and lipids with other lipoproteins

returns cholesterol from peripheral tissues to liver

14
Q

What are the most and least dense lipoproteins?

A
Chylomicrons = least dense
HDL = most dense
15
Q

Why are certain lipoproteins more dense than others?

A

The ones with more proteins relative to TG are more dense

16
Q

What major apolipoproteins are found in VLDLs?

A

B-100
C-II
E

17
Q

What major apolipoproteins are found in chylomicrons?

A

B-48
C-II
E

18
Q

What major apolipoproteins are found in LDLs?

A

B-100

19
Q

What major apolipoproteins are found in HDLs?

A

A-1
C-II
E

20
Q

What two apolipoproteins are encoded on the same gene? A difference in mRNA encoding determines which is produced

A

B-48

B-100

21
Q

Where is apoB-48 produced?

A

intestine

22
Q

Where is apoB-100 produced?

A

liver

23
Q

What is lipoprotein lipase activated by?

A

ApoCII

24
Q

Lipoprotein Lipase is anchored to capillary walls of most tissues by?

A

Heparin sulfate

25
Q

What stimulates the synthesis and secretion of adipose isoenzyme of lipoprotein lipase?

A

insulin

26
Q

Where does the synthesis of lipids primarily occur?

A

In the liver

27
Q

How does acetyl CoA get out of mitochondria?

A

It is changed into citrate

28
Q

What are the two major ingredients for fatty acid synthesis?

A

cytosolic acetyl CoA

NADPH

29
Q

What is an important cofactor for acetyl CoA carboxylase?

A

Biotin

30
Q

What does acetyl CoA Carboxylase do?

A

Produces Malonyl CoA from Acetyl CoA

uses ATP

31
Q

What enzyme sequentially adds 2C units from malonyl CoA to the growing fatty acid chain?

A

Fatty Acid Synthase Complex

32
Q

Oxidation of new fatty acids in mito after they are synthesized is prevented by inhibition of _________
by ___________

A

carnitine palmitoyltransferase (CPT1) by malonyl CoA

33
Q

Where does the elongation of fatty acids occur?

A

ER

34
Q

What organ makes especially long fatty acids?

A

Brain (C22 to C24)

35
Q

What is the end product of fatty acid synthesis?

A

Palmitate (C16)

36
Q

In the elongation of Fatty acids, the fatty acyl chain attached to __________ instead of ACP

A

Coenzyme A

37
Q

Where does desaturation of fatty acids occur?

A

In the ER

38
Q

What is required for the desaturation of fatty acids?

A

molecular oxygen

39
Q

What is the main storage form of fatty acids?

A

triacylglycerols

40
Q

What enzyme in the TG synthesis process is found in the liver but not in adipose tissue? converts glycerol to glycerol-3-phosphate

A

glycerol kinase

41
Q

Fatty acid synthase makes palmitate, that can be _________ and _________

A

elongated

desaturated

42
Q

What stimulates the synthesis and secretion of lipoprotein lipase?

A

Insulin

43
Q

What enzyme breaks down TGs to FAs for release by adipose tissue?

A

Hormone sensitive Lipase

44
Q

What is the key intermediate in phospholipid synthesis from fatty acids?

A

CDP-serine intermediate

45
Q

Which fatty acid of phospholipids tends to be unsaturated?

A

C2 position

46
Q

What is the general class of enzymes that cleave phospholipids at different locations on the molecule?

A

phospholipase

47
Q

Phospholipase A2 cleaves phospholipids in the membrane for ________ synthesis?

A

prostaglandin

48
Q

What type of fatty acid derivative is important for the myelin sheath on nerve cells? and are the antigenic determinants for the ABO blood groups

A

sphingolipids