Introduction to Biochemical Processes

J. Enrique Salcedo-Sora

March 2014

Lecture plan

  • Energy and mass flow (2h)

  • Chemical reactions and energy transduction (2h)

  • Membrane transport of nutrients (2h)

  • Glucose fermentation (2h)

Energy

Energy flow is essential for life. Living systems capture, transform and use energy. But what is energy:

Energy = Heat + Work

Bioenergetics, the study of energy flow in living systems, is based on the same observational facts and the formulation of laws based on observations of the physical world. Bioenergetics therefore, allows the study and calculations about how energy transforms into either heat or work or, most commonly, both.

A formal definition of work: it is the displacement of extensive quantities across a difference of conjugated potentials. Now, let us deconstruct this in a top-down approach, from the macro to the molecular.

The Joule

The amount of work done when a force of 1 newton displaces the point at which it is applied by 1 metre in the direction of the force.

Lets deconstruct this concept.....

How do fleas jump?: With an elastic band!

Most jumping insects have a catapult mechanism to increase the power (rate of work) of their hind legs. The force comes from the elasticity energy stored in molecules of compressed resilin. The release of the 'entropic' energy can take place much faster than energy generated by metabolism, although chemical reactions are required to put resilin under compression in the first place.

Jump 1

Jump 2