CH 28

Question 1

Where does fatty acid synthesis occur in the cell?

Answer 1

The cytoplasm

Question 2

The committed step in fatty acid synthesis is the formation of
___
in a reaction catalyzed by
___

Answer 2

The committed step in fatty acid synthesis is the formation of
malonyl CoA
in a reaction catalyzed by
acetyl CoA carboxylase 1.

Question 3

Fatty acid synthesis begins with a preparatory step in which
____
is transferred from the
____
to the
____
. However, it cannot pass through the membrane, so it is transported as
____
, which is cleaved to
____
and
____
.

In the cytosol, acetyl-CoA is converted to
____
, a three-carbon compound.

Fatty acid synthesis begins with the transfer of the acetyl group from acetyl-CoA to the fatty acid synthase.

__
–carbon groups, supplied by
____
, are added to the growing acyl chain in a series of steps involving condensation, reduction, and dehydration reactions.

Elongation of the fatty acid chain stops at
__
carbon atoms, after
__
cycles, as the free fatty acid is released.

Answer 3

Fatty acid synthesis begins with a preparatory step in which
acetyl-CoA
is transferred from the
mitochondria
to the
cytoplasm
. However, it cannot pass through the membrane, so it is transported as
citrate
, which is cleaved to
acetyl-CoA
and
oxaloacetate
.

In the cytosol, acetyl-CoA is converted to
malonyl-CoA
, a three-carbon compound.

Fatty acid synthesis begins with the transfer of the acetyl group from acetyl-CoA to the fatty acid synthase.

2
–carbon groups, supplied by
malonyl-CoA
, are added to the growing acyl chain in a series of steps involving condensation, reduction, and dehydration reactions.

Elongation of the fatty acid chain stops at
16
carbon atoms, after
7
cycles, as the free fatty acid is released.

Question 4

Select the essential fatty acids.

Answer 4

linoleic acid

linolenic acid

Question 5

Which of the molecules regulate the enzyme that catalyzes malonyl‑CoA synthesis?

Answer 5

citrate

fatty acids or fatty acyl-CoA

Question 6

Which of the enzymes does malonyl‑CoA regulate?

Answer 6

carnitine acyltransferase

Question 7

Which molecules directly participate in fatty acid synthesis by acting as energy sources?

Answer 7

NADPH
ATP

Question 8

Which enzyme directly generates the majority of the acetyl‑CoA used in fatty acid synthesis?

Answer 8

ATP‑citrate lyase