fundamentals of energy metabolism

Question 1

first law of thermodynamics

Answer 1

energy can neither be created nor destroyed but is transferred from one form to another or from one place to another.

Question 2

citric acid cycle

Answer 2

“1st” reaction: Acetyl CoA condenses with oxaloacetate to produce citrate

2 phases:

Decarboxylating (citrate to succinyl CoA)
Reductive (succinyl CoA to oxaloacetate)

Question 3

electron transport chain

Answer 3

The components of the electron transport chain are arranged in a precise fashion in the inner mitochondrial membrane to allow pumping of protons to occur from the matrix to the intermembrane space.

Question 4

ATP yield- TCA cycle and oxidative phosphorylation

Answer 4

In the TCA cycle:
1 GTP (equivalent to 1 ATP) is produced by substrate-level phosphorylation, as well as 3 NADH and 1 FADH2.
It is generally accepted that each NADH oxidised by the electron transport chain yields 2.5 ATP and each FADH2 oxidised yields 1.5 ATP.

Thus the total yield per acetyl CoA is 10 ATP.

Question 5

fatty acid metabolism

Answer 5

Fatty acids and glycerol are released from triglyceride stores in adipose tissue via the action of lipase enzymes.

Fatty acids are transported in the blood as a complex with albumin and are taken up by cells for oxidation.

Fatty acid modification and entry into mitochondria

Beta-oxidation leading to energy (ATP) formation