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Flashcards in Fatty Acid Synthesis Deck (74)
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1

Fatty acids are synthesized primarily in the ___

liver.

2

how to get FA from pyrvuate?

1. pyvuvate --> citrate

2. citrate leaves mitocondira

3. citrate ---> acetyl CoA

3. acetyl CoA --> malonyl CoA

5. manlonyl CoA is 2C donot for FA synthesis

3

____ is 2C donot for FA synthesis

manlonyl CoA

4

what is the product of FA synthesis? what is its structure? 

palmitic acid, a sixteen carbon saturated fatty acid.

5

pyruvate --> Pyruvate dehydrogenase by?? 

Pyruvate dehydrogenase

6

pyruvate --> oxaloacetate (OAA) by?? 

 Pyruvate carboxylase

7

 Pyruvate carboxylase and Pyruvate dehydrogenase  are regulated based on what? 

e level of acetyl CoA in the mitochondria

8

When Acetyl CoA is at high concentration the Pyruvate dehydrogenase is ____

inhibited

9

When Acetyl CoA is at high concentration the Pyruvate dehydrogenase is inhibited causing ----> 

 an INC  Pyruvate carboxylasse ---->INC OAA.

10

The reduction in acetyl CoA leads to 

1.  activation of the dehydrogenase

2. inhibition of carboxylase.

11

What happens with Citrate in the cytosol

cleaved to Acetyl CoA and OAA by Citrate Lyase. 

12

in the cytosol, citrate is cleaved to Acetyl CoA and OAA by ___

Citrate Lyase. 

13

Whybreak down citrate in the cytosol too when you have already produced Acetyl CoA and OAA in the mitochondria?

• The Pyruvate dehydrogenase is only found in the mitochondria.
Acetyl CoA cannot cross the mitochondrial double membrane.

14

NADPH is required for the ___ of Fatty Acids.

NADPH

15

NADPH is required for the synthesis of Fatty Acids.

One source of NADPH for synthesis of FA is the recycling of the OAA

what are the two steps? 

1. OAA is reudced to Malate by  NADH dependent maltase dehydrogenase

2. Malate converted to NADP-dependend Malix enzyme

3. Malic enzyme oxidizes and decboxyltes Malate --> pyruvate

16

sources of NADPH for FA synthesis (2)

1. recycling OAA

2. Pentose Phosphate pathway

17

2 enzymes involved in FA synthesis?

 Acetyl CoA Carboxylase  and  Fatty Acid Synthase

18

___ enzymes is involved in the rate controlling step of FA synthesis

 Acetyl CoA Carboxylase  

19

what rxn does  Acetyl CoA Carboxylase   catlayze in Fa synthesis?

Acetyl CoA ---> Malonyl COA

20

Acetyl CoA ---> Malonyl COA

what is the cofactor ACC binds to?

biotin

21

Acetyl CoA ---> Malonyl COA

waht is consumed? generated?

ATP hydrolysized to ADP + Phosphate

22

What regulates Acetyl CoA Carboxylase?

1. Citrate -- causes it to polymerize

2. Insulin stim. phopshatase

3. Caloric intake/ACC transcription levels

4. Glucagon/Epinephrine stimulated A-Kinase

5. Palmitoyl CoA levels

6. AMP (low energy levels)

23

5 steps in FA synthesis? 

1. Activation: carboxylation of acetyl CoA to malonyl CoA  
2. Condensation: formation of the β -keto group
3. Reduction of the β -keto group
4. Dehydration of the a, b carbons
5. Reduction of the a, b double bond

24

what are steps 2-5 of FA synthesis catalyzed by?

Fatty Acid Synthase (FAS)

25

WHat does Fatty Acid Synthase  do to MALONYL COA? 

takes 2C FROM MALONYL COA, GIVES IT TO GROWING FATTY ACYL CHAIN 

26

each subunit of Fatty Acid Synthase contains (2)

1. 7 catalytic activities

2. an acyl carrier protein in a single polypeptide chain

27

Phosphopantetheine is linked to a serine within the ____) portion of fatty acid synthase

acyl carrier protein (ACP)

28

___ of fatty aci synthase reacts with malonyl COA to form a thioester fond

sulfhydral group

29

fatty acid synthase

the two subunits associate ____o that the phospho-pantetheinyl sulfhydryl group on one subunit is close to the cysteinyl sulfhydryl group on the other subunit.

head-to-tail s

30

what is fatty acid synthase derived from?

pantothemnic acid?