Lipid Metabolism

Question 1

major sites of fatty acid synthesis

Answer 1

liver, lactating titties

Question 2

minor sites of fatty acid synthesis

Answer 2

kidney, adipose tissue

Question 3

precursors of FA synthesis

Answer 3

Acetyl CoA, ATP, NADPH, CO2, Biotin

Question 4

FA synthesis occurs where

Answer 4

cytoplasm, son.

Question 5

configuration of double bonds in unsaturated FA

Answer 5

cis

Question 6

location of double bonds in linolenic acid

Answer 6

9, 12, 15

Question 7

location of double bonds in arachidonic acid

Answer 7

5, 8, 11, 14

Question 8

key intermediate between fat and carbohydrate metabolism

Answer 8

acetyl CoA

Question 9

main source of acetyl CoA for FA synthesis

Answer 9

pyruvate

Question 10

how does acetyl CoA get into the cytoplasm

Answer 10

converted to Citrate via citrate synthase

Question 11

after citrate is in the cytoplasm, what breaks it down to acetyl CoA and OAA

Answer 11

ATP-Citrate lyase

Question 12

enzyme that produces NADPH in cytoplasm for FA synthesis

Answer 12

malic enzyme

Question 13

rate limiting enzyme for FA synthesis

Answer 13

Acetyl CoA Carboxylase (ACC)

Question 14

ACC coenzyme needed

Answer 14

biotin. (because of carboxylase)

Question 15

first committed step of FA synthesis

Answer 15

acetyl CoA to malonyl CoA via ACC

Question 16

shifts ACC toward inactive dimer form

Answer 16

palmitoyl CoA (allosteric regulation)

Question 17

shifts ACC toward active polymer form

Answer 17

Citrate (allosteric regulation)

Question 18

short term inactive regulation of ACC is done by which hormones

Answer 18

glucagon, epi and NE.

Question 19

explain how ACC is phosphorylated due to glucagon presence

Answer 19

cAMP activates pKA. pKA phosphorylates AMPKK, AMPKK phosphorylates AMPK which phosphorylates ACC to make it inactive.

Question 20

FAS can exist as a monomer or dimer. which form is more active

Answer 20

dimer

Question 21

where do the carbons come from when elongating fatty acetyl chain

Answer 21

malonyl CoA. (gives off 2 carbons per molecule)

Question 22

what does FAS need to work

Answer 22

NADPH

Question 23

fatty acyl desaturation & elongation takes place where

Answer 23

ER

Question 24

enzyme that introduces sites of desaturation.

Answer 24

fatty acyl CoA desaturase

Question 25

fatty acyl CoA desaturase introduces double bonds at which positions?

Answer 25

5, 6, or 9

Question 26

fatty acyl desaturase system is an electron transport system in the ER that involves

Answer 26

cytochrome b5, desaturase, NADPH-cytochrome b5 reductase

Question 27

which tissue makes medium chain fatty acids de novo

Answer 27

lactating mammary glands

Question 28

common end product of fatty acid synthesis

Answer 28

palmitate. (immediately converted to palmitoyl CoA)

Question 29

converts palmitate to palmitoyl CoA

Answer 29

fatty acyl CoA synthetase

Question 30

enzyme that forms free palmitate from palmitoyl ACP

Answer 30

thioesterase