Thermodynamics

SECTIONS

	1.	Introduction
	2.	The First Law
	3.	The Second Law
	4.	Gibbs Free Energy
	5.	G, H, S
	6.	Spontaneity
	7.	Relating G, H, S
	8.	Equilibrium
	9.	Review

INTRODUCTION

Thermodynamics, a branch of physics that is concerned with the study of heat (“thermo”) and power (“dynamics”), might at first seem more important for engineers trying to invent a new engine than for biochemists trying to understand the mechanisms of life. However, since chemical reactions involve atoms and molecules that are bound by the laws of physics, studying thermodynamics should be a priority for every aspiring biochemist.

The sun is the source of
all life's energy.

There are two laws of thermodynamics that are important to the study of biochemistry. These two laws have to do with energy and order–both essential for life as we know it. It is easy to understand that our bodies need energy to function–from the visible muscle movement that gets us where we want to go, to the microscopic cellular processes that keep our brains thinking and our organs functioning. Order is also important. Our bodies represent a high degree of order: atoms and molecules are meticulously organized into a complex system ranging in scale from the microscopic to the macroscopic. Atoms are organized into molecules, which are organized into cells, which are in turn organized into the organs, bones, muscles, and skin that make up the human body.

Exercise objective

Learn the basic concepts of thermodynamics necessary for understanding biochemical energetics.