lecture 20

Question 1

How is energy actually generated in the ETC to make ATP?

Answer 1

Oxidative Phosphorylation

Question 2

Oxidative Phosphorylation

Answer 2

• When H atoms reach the ETC (in the matrix), the electron is stripped from it and passed down the cytochrome chain
• Energy from the flow of electrons pumps H+ out of the matrix and into the
  Inter-membrane space of the mitocondria
• This results in an accumulation of H+ in the intermembrane space
• This creates an electrical gradient across the inner membrane of the mitochondria.
  Results in stored potential energy. This energy is used to phosphorlate ADP and Pi to ATP

Question 3

fat breakdown for energy release

Answer 3

tryglycerides will split in the adipocyte into glycerold and 3 fatty acids

• breakdown of triglyceride is called lipolysis
• the enzyme that assists in this process is called lipase

Question 4

fatty acid mobilsation

Answer 4

lipase timulates FA to diffuse from the adipocyte and enter the circulation

• FA bind to the albumin for transport to active tissues = free fatty acid (FFA)
• having reache the muslce site FFA move across the plasma membrane of the cell
• FFA will enter the mitocondria to produce energy

Question 5

glycerol mobilsation

Answer 5

glycerol formed dyring lipolysis diffuses from the adipocyte into the circulaion
- glycerold will enter the cytosol of active muscle cells

Question 6

the role of hormones in fat catabolism

Answer 6

• enpinephrine, norepinephrine
• growth hormone
• glucagon assist in the mobilisation of FFA from adipose tissue and its subsequent breakdown

Question 7

hormones and exercise

Answer 7

Plasma concentrations of these hormones increase during exercise in order to provide active muscles with a continuous supply of fuel (FFA)

Question 8

catabolism of glycerol and fatty acids

Answer 8

step 1 - Triglyceride breaks down to: glycerol and 3xFA
step 2: Glycerol enters the glycolysis pathway at step 5 (3 phospho glycer aldehyde) and degrades to pyruvate.
step 3: Fatty acids enter into a process called - beta oxidation

Question 9

2 events that occur in beta oxidation

Answer 9

1- Hydrogen is carried to the ETC by NAD+ and FAD so to produce ATP via oxidative phosphorlyation
2- Fragments from fatty acids are transformed in Beta oxidation to acetly-CoA
Acetyl CoA then enters the CAC for processing.

Question 10

the role of 02

Answer 10

• Fatty acid breakdown relies on O2 availability

- For Beta-oxidation to proceed, oxygen MUST be available at the end of the ETC.

Question 11

intense exercise and O2 availability

Answer 11

During intense exercise O2 delivery is limited,
CHO (anaerobic glycolysis) and PCr are the preferred fuels during high intensity exercise.
- Lipids are slower at producing fuel than CHO