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Flashcards in Lipids II Deck (45)
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1
Q

citrate cleavage pathway

A

how excess acetyl-CoA is export4ed from teh mitochondria

2
Q

how does citrate get through the innermitochondrial membrane

A

tricarbozyl acid transport

3
Q

what happens with citrate gets into the cytopalsm

A

ATP citrate lyase separates citrate into OAA and acetyl CoA

4
Q

how do you get OAA into the mitochondrial matrix

A

malate dehydrogeanse and malic enzyme convert into pyruvate and CO2

5
Q

what happens when OAA gets converted into pyruvate and CO2

A

turns NADH into NADPH

6
Q

what do high cytoplasmic citrate conc indicate

A

CAC is not able to process all the actyl CoA

7
Q

what does high cytoplasmic citrate trigger

A

glycolysis slows down

FA synthesis ramps up

8
Q

what is the committed step of malonyl CoA

A

Acetyl-CoA caarboxylase

9
Q

how does FA synthesis start

A

transfer of acetyl group for acetyl CoA to acyl carrie rprotein on FA synthase

10
Q

what happens to the acetyl group on FA synthase

A

moves from A site to C site

11
Q

what happens to the empy A site

A

malonyl group transfered ther

12
Q

what happens to the acetyl group on the C site

A

transferred to alpha carbon of teh maloyn group on A site

CO32 released

13
Q

what happens to the acetyl group after its on the alpha carbon

A

keto group on beta carbon is removed, saturated fatty acids transferred back to C site

14
Q

how many carbons is palmitic acid

A

16

15
Q

what do you need to make 1 molecule of pamitic acid

A

8 acetyl CoA
7 ATP
14 NADPH

16
Q

what happens after palmitic acid has been released from FA synthase

A

linked to CoA and modified by elongation and desautration

17
Q

where does elongation of FA take place

A

ER or mitochondria

18
Q

what happens to FA in ER

A

elongated in process similiar to FA syntehsis

19
Q

what happens to FA in mitochondria

A

FA elongaed in process simliar to reverse beta oxidation

20
Q

what end to elongation of FA take plac

A

carboxyl end

21
Q

where does destuartion of FA occur

A

ER

22
Q

what does desaturation of FA require

A

p450 monoxygenase system

23
Q

whawt carbon can you not make a double bond past

A

9

24
Q

what are important features of lipid droplets

A

they are surrounded by phospholipid monolayer
covered with structural proetins
bind to enzymes required for TAG synthesis and degration

25
Q

TAGs

A

triacyglycerols

26
Q

what are the msot active tissues in fat synthesis

A

adipose, liver, muscles

27
Q

synthesis of TAGs requires what

A

glycerol

28
Q

how do activate FA

A

bind to COenzyme A using ATP

29
Q

what is the committed step of fat synthesis

A

acyl-COA dicyglycerol acltransferases (DGAT)

30
Q

what are the 3 signals that regulate fat synthesis and degration

A

nutritional status
engery status
presence of lipids

31
Q

how does insulin affect FA synthesis

A

induces expression of actyl-CoA carboxylase, FA synthase

32
Q

both fatty acid synthase and actyl CoA carboylase is activated by what

A

citrate

33
Q

what happens to FA and TAG synthesis in the fasting state

A

decrease

34
Q

how does cAMP affect FA synthesis

A

activates PKA, which inactivates acetyl-CoA carboxylase

35
Q

what do high levels of AMP activate

A

AMPK, which inactivates acetyl-CoA carboxylase

36
Q

how does malonyl-CoA affect FA degration

A

inhibits

37
Q

what is the main regulated step of FA degration

A

import of FA into mitochondrion by CPT1

38
Q

what inhibits CPT1

A

maylonyl CoA

39
Q

what do free fatty acids stimulate

A

FA degration an dketogensis

40
Q

what do fatty acids bind to

A

PPARalpha

41
Q

PPARalpha

A

transcription activater binds to PPRE in promotre region of genes for fatty acid oxidation and ketogensis

42
Q

really of free fatty acids from adipose tissue is regulated by waht

A

glucagon/insulin ration

43
Q

high glucagon/insulin ration in fasting state leas to what

A

release of FA from adipose tissue

44
Q

how does glucagon leads to realse of FA from adipose tissue

A

activation of PKA via cAMP
PKA activates perilipin and hormone sensitive lipiase
lipase cleaves storage fat, reeases free FAs into circulation

45
Q

function of hormone senstive lipase

A

turns TAG into FFA and glycerol