Fatty Acid Beta Oxidation

Question 1

When Are Fatty Acids used as a source of energy/Fuel?

Answer 1

During rest or moderate exercise fatty acids are primary source of energy

Question 2

What must happen to fats so that it can be used as fuel9ATP?

Answer 2

Triacylglycerol must be broken down to Glycerol and 3 Fatty Acids by hydrolysis via Triacylglycerol

Question 3

Where is triacylglycerol stored?

Answer 3

In adipose tissues/fat cells they are mobilized by Hormone Controlled reaction (glucagon and epinephrine)

Question 4

Once Triacylglycerol is broken down by Triacylglycerol Lipase how do the products get transported through the blood?

Answer 4

1) Glycerol enters bloodstream and is transported to the liver where it is converted to pyruvate or glucose via glycolysis or gluconeogenesis
2) Fatty Acids enter the blood stream attached to albumin and transported to other tissues containing mitochondria and undergoes Beta Oxidation to produce Acetyl CoA, NADH and FADH2

Question 5

Triacylglycerol Lipase

-Function

Answer 5

Is to release fatty acids from triacylglycerol in adipose tissue

Question 6

Triacylglycerol Lipase

-Hormonal Control

Answer 6

Epinephrine/Glucagon binds to 7TM cell receptor and increases activity by the signal transduction pathway

1) 7TM cell receptor
2) G protein
3) Adenylate Cyclase-> cAMP
4) Protein Kinase A
5) Perilipin A
6) Triacylglycerol Lipase-Phosphorylated is ON

Question 7

Perilipin A

-function

Answer 7

Remodels fat droplets making fatty acids more accessible for Triacylglycerol Lipase

Question 8

What is happens to the glycerol when it enters the Liver?

Answer 8

1) Glycerol -> Glycerol 3-Phosphate via Glycerol Kinase at the expense of ATP to ADP
2) Glycerol 3-Phosphate -> DHAP + G3P via Glycerol 3-Phosphate Dehydrogenase at expense of NAD+ to NADH
- which feeds into Glycolysis and gluconeogenesis

Question 9

Once the Fatty Acid’s are in the mitochondria, what happens first before beta oxidation can occur?

Answer 9

They are activated by attaching CoA via thioester bond in the cytoplasm of the outer membrane

2 Step Process:
1) Adenylation by ATP
FA + ATP-> Acyl Adenylate + ADP
-via Acyl Adenylase
-hydrolysis of PPi drives reaction

2) Acyl Adenylate + SH-CoA-> Acyl CoA + AMP
- via Acyl CoA Synthetase

Question 10

Once the Fatty Acid’s are in the mitochondria, what happens second before beta oxidation can occur?

Answer 10

Acyl CoA is transferred into the Mt from the cytoplasm

1) Acyl CoA + Carnitine -> Acyl Carnitine + CoA
- via Carnitine transacylase I located in the inter membrane space
- transfers fatty acid from S to O of Carnitine

2) Carnitine Translocase located on inter membrane of mt
- transports Acyl Carnitine from the inter membrane space into the matrix of the mitochondria

3) Acyl Carnitine + SH-CoA-> Acyl CoA + Carnitine
- via Carnitine transacylase II located in the matrix
- transfers fatty acid from O of carnitine to S of CoA

Question 11

Carnitine

Answer 11

Zwitter ionic alcohol