Reaction feasibility

What is a feasible reaction?

A reaction that is energetically favourable at a certain temperature.

What are the laws of thermodynamics?

Rules that help us to decide how feasible a reaction is.

Can endothermic reactions be feasible and why?

Yes. Although the reaction uses up energy from the surroundings to proceed, it is still feasible because there is an increase in entropy.

What is entropy?

Entropy is a measure of disorder.

What is the second law of thermodynamics?

The state of entropy of the entire universe, as an isolated system, will always increase over time.

What state of matter has the most entropy?

Gases

What is Gibbs free energy (G)?

The energy available in a substance to do work.

G = H -TS

H is enthaply, T is temperature, S is entropy

What is an exergonic reaction?

A reaction that has a negative ΔG, and is therfore thermodynamically feasible.

What is an endergonic reaction?

A reaction that has a positive ΔG, and therfore is not thermodynamically feasible.

How does energy transfer in biological systems work?

Organisms extract energy from environment.

Energy converted into useful forms.

Returning some energy to the environment.

Releasing simpler molecules into the environment.

Making complex molecules inside the organism.

Are living organisms at equilibrium with their surroundings?

No

How much ATP is stored in the body?

ATP is maintained at ~1-2 mmol/kg.

Total ATP in muscle is ~95 g.

Each ATP molecules is recycled 1000-1500 times per day.

What kind of reaction is synthesising ATP?

An unfeasible reaction.