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Flashcards in FA's Synthesis Deck (15)
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1
Q

What are the 4 functions of lipids?

A

fuel storage
structural components
cell signaling
other (insulation, generation of heat)

2
Q

How much would a man weight if TAG was changed to Gylcogen?

A

70kg man weight 134kg (6.75 more energy for fats)

3
Q

FA synthesis occurs primarily in what organ?

Other organs also carry out process?

A

Liver

Also adipose tissue, kidney, brain, lactatiting mammary gland

4
Q

What is the first enzyme in FA synehtesis? What RXn catalyze?

A

Citrate synthase First step in CAC

Shuttle out Citrate into cytoplasm

5
Q

Positive and Negative Regulations of

ATP Citrate synthesis?

A

+: Glucose, insulin induce gene expression
Phosphorylation of enzyme
-: PUFA (Polyunsaturated Fatty Acid), leptin

6
Q

What is the rate limiting step of FA synthesis?

What is used as a cofactor for this enzyme?

A

Conversion of acetyl CoA to malonyl CoA by Acetyl CoA Carboxylase also uses CO2 and ATP
Cofactor: Biotin (B7)

7
Q

Positive and Negative Regulations for Acetyl CoA Carbozylase (ACC)?

A

allosteric binding + citrate ; - Palmate (long chain FA)
Phosphorylation (-)/Dephosphorylation (+)
• Insulin (+) via activation of protein phosphatase
• Epinephrine (-) via activation of protein kinase A
• Glucagon (-) via activation of protein kinase A
• AMP (-) via activation of AMP kinase (energy sensor) Induction/repression
• Gene expression up-regulated by high carb/low fat diet

8
Q

What does Malonyl CoA do for degradation of FA?

A

Works as an inhibitor for carnitine acetyltransferase used for FA degradation so do not occur similtaneously

9
Q

Fatty Acid Sythase is made up of?

A

2 dimers arranged head to tail with 7 enzyme activities and Acyl carrier protein

10
Q

How is the Fatty Acid Synthetase regulated?

A

• Allosteric effect (presence of phosphorylated
sugars) – increase activity
• Induction and repression at gene level
– Insulin and glucocorticoid hormones increase
synthesis
– High carb/low fat diets increase synthesis.
– High fat diets as well as starvation lowers synthesis.
– High PUFA suppresses synthesis

11
Q

What did Leptin Show us?

A

Leptin hormone secreted by adipose tissue (in proportion) and regulated body weight by inhibiting food intake, stimulating energy expenditure
binds in hupothalamus to receptor

12
Q

Where can palmate be enlogated?

What are the two carbon donators?

A

SER and Mitocondria

SER uses Malonyl CoA and Mitocondria Acetyl Co A

13
Q

What enzyme is used as a desaturase? Where can they desaturate on the molecule?

A

Aceyl Co A desaturases

4, 5, 6, 9 only all other require essential FA’s

14
Q

What are the homones that regulate the desaturase?

A

Insulin induce and Polyunsaturated FA will suppress

Cholesterol induces Delta 9, suppresses others

15
Q

What are the Essential FA’s? What can they make?

A

Lenoleic, Lenolenic Acids are Essential
Lenoleic used to make arachadonic acid
Lenolenic used to make eicosapentanoic acid (EPA) (20:5 ω3) and docosahexanoic acid (DHA) (22:6 ω3)