Exam 4 - Lipid Biosynthesis

Question 1

What are 4 functions of Lipids?

Answer 1

Signaling Molecule

Structure of cell - membranes

Energy Storage

Insulation

Question 2

Are all FA synthesized in the body?

Answer 2

No, some are obtained through our diet

Question 3

What is the building block for most lipids?

Answer 3

Some form of Acetyl CoA

Question 4

Fatty Acids are long [] chains with a [] group…

Answer 4

Hydrocarbon

carboxyl

Question 5

[] Fats are made from the hydrogenation of cis fats

Answer 5

Trans

Question 6

Palmetic Acid has how many Carbons?

Stearic Acid has how many Carbons?

Oleic Acid has how many Carbons?

Answer 6

• 16
• 18
• 20?? - double check this

Question 7

Why does the body like to pool Free Fatty acids in the body?

Answer 7

• Psyche!
• The body does not pool free fatty acids because itd be like having a bunch of soap in your body.

Question 8

Rank in order of energy supply ability?

MAG, TAG, DAG

Answer 8

TAG > DAG >MAG

Question 9

Where is the location of Fatty Acid Synthesis?

Answer 9

Cytosol

Question 10

What are the two types of essential Fatty Acids?

Answer 10

Linoleic

Linolenic

Question 11

FA biosynthesis occurs by sequential [] carbon additions to a growing acyl-chain

Includes a:

[] Molecule

Extender Molecule

Answer 11

1. two carbon
2. Starter and Extender

Question 12

Acetly CoA is generated in the [] by breakdown of [], [] and [] ??

Answer 12

1. Mitochondria
2. AA, FA, Pyruvate

Question 13

What is the enzyme that catalyzes the two-carbon additions to the growing acyl chain?

Answer 13

Fatty Acid Synthase

Question 14

Is FAS just one enzyme?

Answer 14

No, it is a collection of enzymatic activity

Question 15

What type of reaction is first catalyzed by FAS and what substrates does it use?

Answer 15

• Condensation
• Involving Acetly-ACP and Malonyl-ACP

Question 16

What is the first committed step of FA biosynthesis?

Answer 16

• Acetyl-CoA Carboxylase - Adds CO2 to Acetly CoA making Malonly-CoA
• Requires 1 ATP

Question 17

[] - uses ATP and bicarbonate to catalyze the addition of CO₂ ont acetyl CoA forming malonyl-CoA…

Where does this reaction take place?

Answer 17

Acetyl -CoA Carboxylase

Cytosol

Question 18

What type of regulation controls ACCase?

Answer 18

Covalent modification

Question 19

What are the two basic stages of FA synthesis?

Answer 19

Priming

Elongation

Question 20

[] transfers the acetyl group from CoA to ACP

Answer 20

Acetyl-CoA-ACP transacylase

Question 21

What does KAS catalyze in the first steps of FAS?

Answer 21

• Transfers the acyl group from the ACP to a Cysteine residue on FAS

Question 22

[] - catalyzes the condensation reaction involving the KAS bound acyl group and the ACP bound malonyl group with release of CO₂ (from malonyl group)

Answer 22

B-ketoacyl-ACP synthase

Question 23

What are the 4 general reactions of the FAS system?

Answer 23

• Condensation
• Reduction
• Dehydration
• Reduction

Question 24

What does B-ketoacyl-ACP-reductase do in FAS?

Answer 24

Reduces the B-keto group to a hydroxyl group using electrons from NADPH

Question 25

[] - removes a water molecule forming an enoyl group

Answer 25

B-hydroxyacyl-ACP dehydratase

Question 26

What is the final step of elongation in FAS?

Answer 26

* Reduction of enoyl group using electrons from NADPH to form a four carbon FA - butyryl-ACP * Enoyl-ACP reductase

Question 27

How many times must elongation in FAS occur to reach a 16 carbon polmitoyl-ACP?

Answer 27

7 times.

Question 28

What "portion" of FAS removes the final carbon chain from the final ACP group so that elongation can continue?

Answer 28

KAS

Question 29

This enzyme terminates elongation by catalyzing the hydrolysis of the thioester linkage between the acyl group and ACP?

Answer 29

Acyl-ACP Thiesterase

Question 30

How much ATP must be spent to form 1 molecule of palmitic acid?

Answer 30

* 15 ATP * 8 ATP for Citrate --\> Acetly CoA * 7 ATP for Acetyl-CoA --\> Malonyl-CoA * 14 NADPH * 8 from malic enzyme * 6 from pentose phosphate pathway * 2.5 ATP for each NADPH!

Question 31

What is the difference between Prokaryotic and Eukaryotic FAS?

Answer 31

* Eukaryotic - multifunctional protein * Prokaryotic - multicomponent protein complex

Question 32

What are the three fates of Palmitate?

Answer 32

* Elongation * Desaturation * Hydroxylatiobn

Question 33

1. Elongation in the mitochondria uses [] - [] long carbons? 2. This doesn't use [] acid

Answer 33

1. 10-14 Carbons 2. Palmitic Acid

Question 34

Where does Palmitic Acid elongation take place?

Answer 34

ER and Mitochondria

Question 35

Where does desaturation of Palmitic Acid take place?

Answer 35

ER

Question 36

[]-[] fatty acids are produced in mitochondria and nervous tissue

Answer 36

alpha-hydroxy

Question 37

De Novo production of additional Fatty Acids 1. Bulk product of FAS is [] 2. [] chain fatty acids can be made in some secretory glands 3. [] [] can be formed from acyl-CoA 1. these are dominate in nervous system []

Answer 37

1. Palmitate 2. Branched 3. Fatty Alcohols 1. membranes