Synthesis of fatty acids

Question 1

what is fatty acid synthesis not the reverse of

Answer 1

b oxidation

Question 2

where does fatty acid synthesis occur

Answer 2

in the cystol of our liver cells and in lactating mammary glands

Question 3

what are the reductants in fatty acid synthesis

Answer 3

NADPH

Question 4

why does elongation occur

Answer 4

due to the sequential addition of two carbon units derived from the acetyl CoA

Question 5

when does elongation stop

Answer 5

at 16 carbohydrates

Question 6

where are enzymes attached

Answer 6

to a single poly peptide chain “fatty acid synthase”

Question 7

how do we remove xs citrate from the TCA cycle

Answer 7

via the pyruvate malate cycle

Question 8

how does the pyruvate malate cycle work

Answer 8

citrate is moved out of the matrix by a transport protein and then converted back into oxaloacetate and Acetyl CoA by ATP citrate lyase using ATP

Question 9

why is the pyruvate malate cycle important

Answer 9

it is a way of getting citrate out of the cycle

and it is a source of NADPH production

Question 10

what is insulin uprugulate

Answer 10

ATP citrate lyase

Question 11

what is the RDS in forming fatty acids

Answer 11

malonyl CoA step

Question 12

describe the formation of malonyl coA

Answer 12

CO2- biotin enzyme + acetyl coA —-> malonyl coA + biotin enzyme using the enzyme acetyl coA carboxylase( biotin) and citrate

Question 13

how is the formation of of malonyl coA regulated

Answer 13

by a high AMP:ATP ratio
and by insulin
and glucagon and epinephrine( inhibit phosphatase)

Question 14

how does a high AMP:ATP ratio regulate malonyl coA formation

Answer 14

as the enzyme kinase is used and ATP to inactivate the acetyl CoA carboxylase enzyme

Question 15

how does insulin regulate malonyl coA formation

Answer 15

as insulin up regulates the enzyme phosphatase which converts the inactive form of acetyl coA carboxylase into the activated from

Question 16

what is a derivative of pantothenic acid (vitamin B5)

Answer 16

4’ phosphopentetheine

Question 17

what does 4’ phosphopentetheine carry units

Answer 17

acetyl and acyl units on the terminal thiol group during fatty acid synthesis

Question 18

describe step 1

Answer 18

acetyl coA + ACP-SH via the enzyme Acetyl Coa ACP transacylase—> to form acetyl S ACP + coA

Question 19

what is the end product of fatty acids synthesis

Answer 19

palmitate

Question 20

describe step 2

Answer 20

the transfer from Acetyl S ACP+ enzyme SH—->acetyl s enzyme + ACP -SH

Question 21

describe step 3

Answer 21

malonyl coA + ACP-SH—> Malonyl- S-ACP + CoA

via malonyl CoA-ACP transacylase

Question 22

describe step 4

Answer 22

malonyl S ACP+ acetyl S enzyme —-> acetoacetyl S ACP and also removes one co2 MOLECULE

Question 23

how many cycles of the fatty acid synthesis occurs to produce a 16 carbon chain

Answer 23

7

as 2 come from malonyl every time

Question 24

what are the end products

Answer 24

7 CO2 PRODUCED
7 ATP USED
14 NADPH UTILISED

Question 25

describe step 5 of fatty acid synthesis

Answer 25

acetoacetyl-S-ACP + NADPH +H+----> Beta hydroxybutyryl ACP + oxidised NADP via the b ketoaceyl ACP reductase

Question 26

describe step 6

Answer 26

Beta hydroxybutyryl ACP is dehydrated to form crotonyl S ACP

Question 27

describe step 7

Answer 27

crotonyl S ACP + NADPH +H+ ----> butyrylS ACP + oxidised NADP

Question 28

what might palmitate lengthen to form

Answer 28

stearate 18C

Question 29

where are the lengthening enzymes found

Answer 29

on the ER and in the mitochondria

Question 30

which pathway do we use for the lengthening of short chain fatty acids

Answer 30

mitochondrial pathway

Question 31

which three enzymes are found in the desaturation of fatty acids

Answer 31

NADH cytochrome b5 reductase cytochrome b5 fatty acid desaturase

Question 32

where do mammalian systems produce double bonds

Answer 32

at the 2,,5,6,9 positions

Question 33

how can double bonds be in molecules

Answer 33

cis and trans

Question 34

what can arachidonic acid be produced by

Answer 34

from linoleic acid through the destraturation and elengation

Question 35

why is arachondonic acid important

Answer 35

important in biological signalling molecules that act as short range messengers

Question 36

what is arachodonic acid converted into

Answer 36

prostaglandins forming an intermediate prostaglandin H2

Question 37

what can prostaglandin H2 form

Answer 37

prostacyclin other prostaglandins thromboxane

Question 38

what does prostacyclin do

Answer 38

inhibits platelet activation also a vasodilator

Question 39

what do other prostaglandins do

Answer 39

inflammatory response production of pain and fever

Question 40

what do thromboxane do

Answer 40

vascoconstrictor hypersensitive agent and facilitates platelet aggregation

Question 41

which drugs inhibits the prostaglandin synthase

Answer 41

aspirin

Question 42

what does aspirin inhibit

Answer 42

the cyclooxyrgenase activity of COX

Question 43

what do NON STEROIDAL ANTI INFLAMMATORY DRUGS block

Answer 43

cox 2

Question 44

what side effects occur when cox 2 is inhibited

Answer 44

stomach ulceration and kidney damage

Question 45

what binds with adipocytes

Answer 45

monoacylglycerols diacylglycerols triacylglycerols to form micelles

Question 46

how dow e activate fatty acids to form TAG

Answer 46

BY fatty acid and fatty acyl coA synthetase and ATP to from fatty acyl COA

Question 47

what is the initial accept of fatty acids during the synthesis of TAG

Answer 47

g3p

Question 48

how is G3P produced

Answer 48

from glucose to DHAP and then g3P in glycolysis OR glycerol and glycerol kinase in the liver

Question 49

describe TAG synthesis

Answer 49

G3P to PHOSPHATIDATE by acyltransferase | phosphatide to diacylglycerol by phosphatase and then diacylglycerol to TAG via acyltransferase