LECTURE 24

Question 1

common in many lipids and in TG?

Answer 1

palmitic acid
stearic acid
oleic acid

Question 2

how many carbons comprise palmitic acid?

Answer 2

16:0

Question 3

how many carbons comprise stearic acid?

Answer 3

18:0

Question 4

how many carbons comprise oleic acid?

Answer 4

18:1

Question 5

these are essential FA’s because we can’t synthesize them?

Answer 5

linoleic acid

linolenic acid

Question 6

how many carbons comprise linoleic acid?

Answer 6

18:2

Question 7

how many carbons comprise linolenic acid?

Answer 7

18:3

Question 8

this is a fatty acid made from linoleates and is precursor of PGs?

Answer 8

arachidonic acid

Question 9

how many carbons comprise arachidonic acid?

Answer 9

20:4

Question 10

these contain FAs of 24 carbons, so name this FA and example?

Answer 10

cerebrosides

nervonic acid

Question 11

where does fatty acid synthesis primarily occur?

Answer 11

Liver and mammary cells

Question 12

where does fatty acid synthesis start? describe the initial step that starts the process?

Answer 12

mitochondrial matrix of the liver and mammary cells

AcCoA to citrate via citrate synthase with OAA in the mitochondrial matrix then into the cytosol via citrate transporter and converted to Acetyl CoA via citrate lyase where OAA is also released

Question 13

what converts the AcCoA to malonyl CoA? why is this significant?

stimulated by?
inhibited by?

keep in mind that malonyl CoA is converted to malonyl ACP, what enzyme is this?

Answer 13

acetyl CoA carboxylase

key regulatory enzyme for fatty acid synthesis

stimulated by citrate and insulin
inhibited by malonyl CoA, palmitoyl CoA and epinephrine

malonyl transacylase

Question 14

what energizes AcCoA? what is the necessary cofactor for holding the activated CO2?

Answer 14

carboxylation

biotin

Question 15

what converts Acetyl CoA to Acetyl ACP?

Answer 15

acetyl transacylase

Question 16

how does the cycle continue when we finally have the ACP substrates, just name the important concepts?

Answer 16

both converted to acetoacetyl-ACP via acyl-malonyl ACP condensing enzyme

this is converted to D-3 hydroxybutyric ACP by B-ketoacyl-ACP reductase, NADPH is also used

D-3 hydroxybutyric ACP to Crotonyl-ACP via 3-hydroxyacyl-ACP dehydratase, H2O released

Crotonyl-ACP to Butyric ACP via enoyl ACP reductase, another NADPH used

Question 17

what can Acetyl CoA use in place of AcCoA? what is unique about the carbon yield

Answer 17

Propional CoA which yields FAs with odd# of carbons

Question 18

what are the products after fatty acid synthesis is finished?

Answer 18

8 AcCoA with 7 ATPs, 14 NADPHs used and 7 HCO3 to yield palmitate, 8 CoA, 7 ADP, 14 NADP, 7 CO2, 7 Pi

Question 19

what is the other source for NADPH?

Answer 19

citrate to acetyl CoA than to the fatty acid synthesis cycle

Question 20

how is palmitate made into longer chains and can become unsaturated if this is the product?

Answer 20

it goes to the mitochondria or microsome on the ER where malonyl CoA is added to the carboxyl end of the acyls to elongate them

Question 21

what is a TAG comprised of?

Answer 21

glycerol and 3 fatty acids

Question 22

where does most denovo synthesis of TGs occur?

Answer 22

liver and adipocytes

Question 23

what converts the DHAP and glycerol -PO4?

Answer 23

glycerol-PO4 dehydrogenase providing the backbone to build off

Question 24

what are the sources for glycerol-PO4 synthesis?

Answer 24

liver and cytosol

Question 25

what activates the fatty acid, the glycerol-PO4 to start the elongation process?

in this process what is the simplest phospholipid? the second messenger?

this final product is stored in the liver or packaged in VLDLs for export to the body?

Answer 25

fatty acyl CoA synthase

phosphatidate
diacylglycerol

TAG