Three Laws of Thermodynamics and Metabolism related

1. The Conservation of Energy. The amount of energy in the universe is constant. Energy cannot be created or destroyed but may be converted from one form to another. 

The First Law applies to metabolism in the sense that energy is not free. For example, if the body needs to do a certain amount of work - let's say 5 kJ - the body needs to consume 5 kJ of chemical energy in the form of food to do the 5 kJ of work required. Any energy that is released by an exergonic reaction is absorbed by the surroundings. Conversely, any energy that is stored by an endergonic reaction causes a commensurate decrease in energy of the surroundings.

2. The Law of Entropy. The entropy in an isolated system increases with any changes that occur. All spontaneous events act to increase total entropy.

The Second Law of Thermodynamics is primarily concerned with whether or not a given process is possible. The Second Law states that no natural process can occur unless it is accompanied by an increase in the entropy of the universe.Stated differently, an isolated system will always tend to disorder. Living organisms are often mistakenly believed to defy the Second Law because they are able to increase their level of organization. To correct this misinterpretation, only must simply refer to the definition of systems and boundaries. A living organism is an open system, able to exchange both matter and energy with its environment. Take, for example, the assembly of a virus molecule from its subunits, which clearly involves an increase of order. If the virus is considered an isolated system, this process would be in defiance of the Second Law. However, a virus molecule interacts directly with its environment. The assembly of a virus molecule results in an increase of entropy in the system as a whole due to the liberation of water of solvation from the components and the resulting increase in rotational and translational entropy of the solvent.

3. Absolute Zero. Absolute zero is the temperature (-273°C) at which all thermal kinetic energy ceases. Nothing can be colder than absolute zero. 

Metabolism is unable to proceed at extremely low temperatures close to absolute zero because of the fact that all molecular motion ceases, making chemical reaction unable to occur. Also, enzymes are unable to function at extremely high and extremely low temperatures.