Energy Metabolism

Question 1

What is an exergonic reaction

Answer 1

A spontaneous reaction that releases energy, this energy can then be used to power other reactions

Question 2

What is an endogonic reaction

Answer 2

A reaction that is not spontaneous. It requires the input of energy from exogonic reactions

Question 3

What is reaction coupling

Answer 3

When an unfavourable reaction is coupled with a favourable one. The overall free energy is slightly negative, allowing for the reaction to take place

Question 4

Where is the energy (that gets released) stored in ATP

Answer 4

The phosphoanhydride bond

Question 5

Where does the energy potential in NADH come from

Answer 5

It’s reducing power

Question 6

What is the inverse of glycolysis

Answer 6

Gluconeogenesis

Question 7

What is a futile cycle in glycolysis

Answer 7

When the pyruvate formed at the end of glycolysis enters the gluconeogenesis cycle and is converted back into glucose, essentially wasting energy

Question 8

How is glycolysis and gluconeogenesis regulated

Answer 8

Energy poor molecules (e.g. ADP) promote glycolysis
Energy rich molecules (e.g. ATP) promote gluconeogenesis

Question 9

What is a key molecule in the regulation of glycolysis and gluconeogenesis

Answer 9

Fructose-2,6-bisphosphate
Binds to the allosteric site of both phosphofructokinase-1 (which powers glycolysis) and fuctose-6-bisphosphate-1 (which powers gluconeogenesis)
It enables PFK-1 and inhibits FBP-1
This means that high levels of Fructose-2,6-bisphosphate will result in lots of glycolysis and little gluconeogenesis