Section 3 - Compartmentalization of Lipid Metabolism and FA Synth.

Question 1

FA synthesis occurs in

Answer 1

Cytosol (chloroplasts of plants)

Question 2

FA elongation occurs in

Answer 2

Mitochondria and ER

Question 3

PL synthesis occurs in

Answer 3

ER

Question 4

The long carbon chains of FA are assembled in a

Answer 4

Repeating four-step reaction sequence

Question 5

These 4-step reaction sequences yield

Answer 5

a saturated acyl group (FA) which becomes the substrate for condensation with an activated malonyl group (contributes 2 carbons)

Question 6

Each time the fatty acyl chain passes through the cycle, the FA chain is lengthened by

Answer 6

2 carbons (repeats until 16 carbons long)

Question 7

When the acyl chain reaches 16 carbons

Answer 7

the product leaves the cycle

Question 8

The product after 16 carbons are added

Answer 8

Palmitic Acid 16:0

Question 9

Carbons are added in the direction of

Answer 9

16 –> 1

Question 10

Carbons 15 and 16 in the palmitate molecule are derived from

Answer 10

the methyl and carboxyl carbon atoms of the acetyl-CoA that initially primed the cycle

Question 11

All the other carbon atoms in the FA chain are derived from

Answer 11

acetyl-CoA by the way of malonyl-CoA

Question 12

All of the reactions of FA synthesis are carried out by

Answer 12

Fatty Acid Synthase

Question 13

Fatty Acid Synthase

Answer 13

A multi enzyme complex with 7 separate activiites

Question 14

In bacteria and plants, there are

Answer 14

7 activities in 7 different polypeptides

Question 15

In yeast there are

Answer 15

7 activités in 2 separate polypeptides

Question 16

In vertebrates, there are

Answer 16

7 activities in a single large polypeptide

Question 17

The biosynthesis of FA requires

Answer 17

1. Acetyl-CoA
2. ATP
3. NADPH

Question 18

The group transfer potential of ATP is used to

Answer 18

Add CO2 to acetyl-CoA to form malonyl-CoA

Question 19

NADPH is used to

Answer 19

Reduce the double bonds that are inserted in the growing acyl chain when malonyl-CoA condenses with acetyl-CoA

Question 20

Palmitic acid serves as the

Answer 20

precursor for the biosynthesis of long-chain saturated FAs in animal cells

Question 21

C-18, C-20, and longer FA are formed by

Answer 21

FA elongation systems in the Smooth ER and mitochondria

Question 22

Palmitoyl-CoA is extended by 2 carbons to form

Answer 22

Stearoyl-CoA
This process involves different enzymes than those involved in palmitate synthesis, and CoA is the acyl carrier rather than ACP

Question 23

Palmitoyl-CoA to Stearoyl-CoA

Answer 23

2 carbons are donated by malonyl-CoA, the reduction, dehydration, and reduction
CoA is the acyl carrier, not ACP

Question 24

Unsaturated FAs are formed by the action of

Answer 24

Fatty Acyl-CoA Desaturases

Question 25

Fatty Acyl-CoA Desaturases are

Answer 25

types of mixed function oxidases that make double bonds

Question 26

Mixed function oxidase

Answer 26

When the enzyme oxidizes two entirely different substrates simultaneously

Question 27

In the case of fatty acyl-CoA desaturases, the two different substrates are the

Answer 27

Fatty Acid and NADH or NADPH

These two substrates undergo simultaneous 2-electron oxidations

Question 28

Removal of prostaglandins

Answer 28

cures pain

build up of these causes inflammation

Question 29

Aspirin effect on prostaglandins

Answer 29

Aspirin inhibits cyclooxgenase activity of COX by acetylating the amino acid

Question 30

FA can be desaturated (add double bonds) while

Answer 30

attached to the phospholipid

Question 31

Phospholipids containing arachidonate

Answer 31

If arachidonate is released from PL it can be acted on by COX causing cyclization and removal of double bonds converting it into prostaglandins