Fatty Acid metabolism

Question 1

What contains more energy- fatty acids or glucose?

and why?

Answer 1

Fatty acids as they only produce triglycerides

Glucose produces glycogen + 2x mass odf H2O

Question 2

What are the 3 types of lipases?

Answer 2

ATGL- Adipose TG Lipases
HSL- Hormone-sensitive Lipase
MGL- Monoacylglycerol Lipase

Question 3

Can fatty acids bind the Human Serum Albumin?

Answer 3

FREE fatty acids can bind

Question 4

How are Fatty Acids hydrolysed and how do Fatty acids enter the cells?

Answer 4

After FA are hydrolysed and bind to Human serum Albumin,

they unbind and are activated at the outer membrane of a mitochondrion

Question 5

State the equation for Fatty Acid activation

Answer 5

FA + Co-A -> Acyl CoA
( catalysed by Acyl CoA synthetase which is ATP consuming)

It is 2 steps
FA + ATP-> Acyl adenylate + PPi

Acyl Adenylate + HS-CoA -> ACl CoA + AMP

Question 6

Describe the entry of the FA into the mitochondria.

Answer 6

Acyl-CoA can cross outer
mitochondrial membrane
CoA must be swapped for 
carnitine to cross the inner 
mitochondrial membrane
 Acyl-carnitine is transported
across the bilayer by a
Translocase antiporter
 Acyl chain is reattached to 
CoA once in the matrix

Question 7

In Beta oxidation. Where is the first cleavage?

Answer 7

Next to the Beta carbon

Question 8

In beta oxidation, what are the products?

And where are they used?

Answer 8

Acetyl CoA- used in TCA cycle

Acyl CoA- round 2 of beta oxidation

Question 9

In beta oxidation how many steps is it to release each 2C for a FA?

Answer 9

4 steps

Question 10

Describe the first step of the Beta oxidation mechanism

Answer 10

ACyl CoA-> Trans- Triangle squared- Enoyl CoA

With FAD-> FADH2 and oxidation of alpha and beta carbons

Question 11

Where does the FADH2 produced in the first step f beta oxidation go?

Answer 11

To the ETC

Question 12

How does PUFA get a trans double bond?

In beta oxidation

Answer 12

Additional isomerase enzymes to convert cis-double bond to trans double bond.

Question 13

Describe the 2nd step of the Beta oxidation mechanism

Answer 13

Trans- delta squared-Enoyl CoA -> L-3-Hydroxyacl CoA

Hydration reaction
w/ hydratase

Question 14

Describe the 3rd step of the Beta oxidation mechanism

Answer 14

L-3-Hydroxyacl CoA->3-ketoacyl CoA

dehydrogenase
w/ NAD+ to NADH to the ETC
and dehydrogenase

Question 15

Describe the 4th step in the beta oxidation mechanism

Answer 15

3-Ketoacyl CoA -> Acyl CoA + Acetl CoA

w/ thiolase and COA

Question 16

Where do the products from the 4th step of beta oxidation go?

Answer 16

Go to the TCA cycle

Question 17

What is produced each cycle of the beta oxidation?

Answer 17

1x Acetyl CoA
1x FADH2
1x NADH

Question 18

How do you know how many cycle are in the beta oxidation?

Answer 18

carbons/2 -1

Question 19

7 cycles means how much CoA, FAD and NAD+ is needed for the reaction?

Answer 19

8 CoA
7 FAD
7 NAD+

Question 20

7 cycles produces how much Acetyl CoA, FADH2, NADH H+

Answer 20

8 Acetyl CoA,
7 FADH2,
7 NADH
7 H+

Question 21

7 cycles produces how much ATP

Answer 21

Each NADH=3
FADH= 2
Acetyl CoA= 12

SO 129 ATP

Question 22

What are ketone bodies and when are they made?

Answer 22

When Acetyl CoA builds up in the liver beyond the capacity
of the TCA cycle to use it, ketone bodies are made
. This happens during period of starvation when the level of TG Hydrolysis is

Question 23

Why are ketone bodies a rapid source of energy?

Answer 23

Require little conversion to enter the TCA cycle

Question 24

Describe Ketogenesis
How many steps
What are the products

Answer 24

4 steps

Products= Acetone and D-beta Hydroxybutyrate

Question 25

What ketone bodies are used as fuel?

Answer 25

Acetoacetate

Beta hydroxybutyrate

Question 26

How does KB react in destination tissue?

Answer 26

Acetoacetyl-CoA is
recreated, then split into
2 x Acetyl CoA