Chapter 24 (Desaturases/Elongation/Eicosanoids)

Question 1

Which Cytochrome is associated with desaturases

Answer 1

Cyto b3

Question 2

All desaturases make (cis/trans) double bonds

Answer 2

cis

Question 3

In order to use a desaturase we need to:

Answer 3

active the acid by using acetyl-CoA synthetase

Question 4

Mammals cannot synthesize double bonds on FA after C#

Answer 4

10

Hence the need for essential FAs

Question 5

Trans FAs are bad because:

Answer 5

They inhibit desaturases

Question 6

Delta 9 Desaturase (enzyme)

Answer 6

Will add a double bond after C#9
Requires: O2 + NADH
Produces: 2 H2O + NAD+
Irreversible

Question 7

The #e- from Desaturase will go to:

Answer 7

4e-

to the conversion of Stearoyl-CoA + O2 to Oleoyl Coa + 2 H2O

Question 8

Elongase

Answer 8

Adds a Malonyl-CoA to the S-CoA end of a FA
Requires: Malonyl-CoA
Produces: CO2 + CoA
Irreversible

Question 9

Beta-Ketoacyl-CoA Reductase

Answer 9

Turns the carbonyl group on gamma carbon into a hydroxyl group
Requires: NADPH + H
Produces: NADP+

Question 10

Beta-hydroxyacyl-CoA Dehydrogenase

Answer 10

Turns the hydroxyl group on the gamma carbon into a double bond between the beta and gamma carbons
Produces: H2O
Irreversible

Question 11

Enoyl-CoA Reductase

Answer 11

Completely reduces the double bond between the gamma and beta carbons
Requires: NADPH + H
Produces: NADP+

Question 12

All enzymes that are associated with FA elongation are attached to ___

Answer 12

CoA

Question 13

Whats involved in going from an activated (S-CoA) FA back to a normal FA (COO-)

Answer 13

It is a nonenzymatic reaction
Requires: H2O
Produces: CoA

Question 14

Arachidonate is only synthesized by ___

Answer 14

mammals

Question 15

Arachidonic Acid is synthesized from ___

Answer 15

Linoleate (which we get from our diet)