W5- Lecture 24- fatty acid synthesis

Question 1

describe fatty acid synthesis step 1

rate limiting factor ?

Answer 1

production of malonyl CoA from Acetyl CoA
this is catalysed by Acetyl CoA carboxylase
with the use of HCO3-(bicorbonate ) and ATP
outputting Pi + ADP

rate limiting- biotic cofactor Acetyl CoA carboxylase

Question 2

describe fatty acid synthesis step 2

Answer 2

production of Acetyl-ACP +Malonyl-ACP
Acetyl-ACP is produced from Acetyl CoA
catalysed by Acetyl transacylase
conversting ACP to CoA in the process

Malonyl-ACP is produced by malonyl CoA
catalysed by malonyl transacylase
again converting ACP to CoA

Question 3

how many carbons does each loop of fatty acid synthesis add on ?

Answer 3

2 carbons from condensation with Malonyl-ACP

Question 4

what what point does the synthetic cycle stop ?
where does it take place ?
how many ATP used
how many NADPH

Answer 4

until C16 palmitoyl-ACP is formed.
in cytosol

7 ATP
14 NADPH

Question 5

Where does Further extension and de-saturation of palmitoyl-ACP take place

Answer 5

smooth endoplasmic reticulum

Question 6

where is Acetyl-coA available?

Answer 6

in mitochondria

Question 7

how is Acetyl-coA transported into the cytosol ?

how is this process able to be recycled ?

Answer 7

Acetyl-coA + oxaloacetate = citrate
citrate transported into cytosol
citrate + ATP= cetyl-coA + oxaloacetate + ADP+Pi

oxaloacetate + NADPH + H+=NAD+ +Malate
catalysed by malate dehydrogenase

Malate + NADP+ = pyruvate + NADPH + CO2

Pyruvate transported into mitochondria
Pyruvate + CO2 +ATP=oxaloacetate+ ADP +Pi
catalysed by pyruvate carboxylase