Beta-Oxidation

Question 1

What is the starting input for beta-oxidation and what is the final output?

Answer 1

Fatty acids (specifically acyl CoA) are the input required for beta-oxidation to begin.
The most important output of beta-oxidation is acetyl CoA and the reduced coenzymes FADH2 and NADH. 
Each time beta-oxidation is completed one NADH, one FADH2 and one acetyl CoA are made.

Question 2

Where does the input required for beta-oxidation come from?

Answer 2

The fatty acids required as the input come from triacylglycerol
(TAG).
TAGs are the fat storage compounds found in the adipose tissues.
TAG mobilisations allows a TAG to be broken down into three fatty acids and one
glycerol.
The fatty acids can then be used for beta-oxidation.

Question 3

What modification is required so that the fatty acid can be used to start beta-oxidation?
How is the fatty acid derivative moved into the mitochondria where beta-oxidation takes
place?

Answer 3

Before the fatty acid can be used in beta-oxidation, the fatty acid must attach to a
CoA.
After CoA attached to a fatty acid, the compound is called an acyl CoA. Acyl CoA must then move into the matrix of the mitochondria (from the cytosol).
The carnitine transport system is used to facilitate the movement of acyl CoA into
the matrix of the mitochondria (where beta-oxidation occurs).

Question 4

What is the final output of beta-oxidation used for?

For what purpose?

Answer 4

The Acetyl CoA produced in beta-oxidation is taken to the (CAC)
Each cycle of the CAC requires one acetyl CoA to begin.
The citric acid cycle produces many electron rich coenzymes that are then taken to
the ETC.
The combination of the ETC and oxidative phosphorylation (OP) allow a lot of ATP to be made.
The electron rich coenzymes produces in beta-oxidation are also taken to the ETC/OP and used to generate ATP.

Question 5

Why is it necessary for us to perform beta-oxidation?

Why is it important?

Answer 5

Beta-oxidation is needed to produce a lot of acetyl CoA which are used to generate ATP (via CAC, ETC and OP). Ultimately, beta-oxidation is a
vital step to generate energy from lipid.

Question 6

How many cycles of beta-oxidation are required to fully break down lauric acid into
acetyl CoA?

Answer 6

5 cycles of beta-oxidation are required to breakdown lauric acid.

Question 7

How many acetyl CoA units are produced from lauric acid via beta-oxidation in total?

Answer 7

The complete breakdown of lauric acid in beta-oxidation produces 6 acetyl
CoA

Question 8

How many NADH and FADH2 (electron rich coenzymes) are produced in each beta-oxidation cycle?

Answer 8

Each beta-oxidation cycle produces 1 NADH and 1 FADH2

Question 9

How many NADH and FADH2 (electron rich coenzymes) are produced in total from the beta-oxidation cycles needed to convert lauric acid in many units of acetyl CoA?

Answer 9

5 NADH and 5 FADH2 are generated in the breakdown of lauric acid.

Question 10

How many NADH and FADH2 (electron rich coenzymes) are produced in the citric acid cycle (CAC) from a single acetyl CoA (made in beta oxidation)?

Answer 10

Each acetyl CoA allows one cycle of the CAC to be completed, which creates 3
NADH and 1 FADH2

Question 11

How many NADH and FADH2 (electron rich coenzymes) are produced from six acetyl CoA (produce in beta oxidation) via the citric acid cycle?

Answer 11

Each acetyl CoA allows one cycle of the CAC to be completed, which creates 3
NADH and 1 FADH2. So six CACs produce 18 NADH and 6 FADH2

Question 12

Each CAC produces 1 GTP which is equivalent to 1 ATP. How many ATP equivalents are produced in from the six CACs?

Answer 12

6 GTP which are equivalent to 6 ATP are produced in the six CACs