Sean - B oxidation Question

Question 1

List the molecules of B-oxidation of saturated fats
(5)

Answer 1

Palmitoyl-CoA
Trans-Delta2-Enoyl-CoA
L-B-Hydroxy-acyl-CoA
B-Ketoacyl-CoA
(Cn) Fatty Acyl CoA + Acetyl CoA

Question 2

List the enzymes of B-oxidation of saturated fats
(4)

Answer 2

Acyl-CoA dehydrogenase
Enoyl-CoA hydratase
B-hydroxyacyl-CoA dehydrogenase
thiolase

Question 3

What happens in the first step of B-oxidation
(4)

Answer 3

Palmitoyl-CoA is converted into Trans-Delta2- Enoyl CoA

Acyl-CoA dehydrogenase catalyses the formation of a double bond at B carbon by removal of 2 H

The 2H are donated to FAD to form FADH2

Electrons are then transferred from FADH2 to the electron transport chain

Question 4

What is the second step in the B-oxidation of saturated fats
(3)

Answer 4

H2O is added across the double bond between the alpha and beta carbons

Catalysed by enoyl-CoA hydratase

The hydroxyl group is always added to the B group (B-oxidation)

Question 5

What happens in reaction 3 of the B-oxidation of saturated fatty acids?
(4)

Answer 5

Two hydrogens are removed from the B carbon to form a carboxyl group

Catalysed by B-hydroxyacyl-CoA dehydrogenase

NAD+ is reduced to NADH (accepts electrons)

NADH then donates it’s electrons to the electron transport chain to generate ATP

Question 6

What happens in reaction 4 of the B-oxidation of fatty acids?
(6)

Answer 6

The sulphur of a CoA-SH molecule attacks the chain (between a and B)

This causes the chain to split, with a 2 carbon acetyl group and a fatty acyl-CoA group being formed

The 2 carbon acetyl group covalently attaches to the CoA to form Acetyl Co-A

The fatty acyl-CoA will undergo B-oxidation again to produce more acetyl-CoA

The acetyl-CoA produced is fed into the citric acid cycle

Catalysed by thiolase (acyl-CoA acetyltransferase)