Question

1. what are the two laws of thermodynamics?
2. Explain how these two laws are related to metabolism or biological process.

Answer 1

The first law of thermodynamics states that energy can neither be created nor destroyed.It can only be converted from one form to another. This is related to metabolism in biological processes such as photosynthesis, glycolysis etc. In photosynthesis light energy is converted to starch or chemical energy.Similarly in glycolysis, the potential enery stored in the bonds of glucose is converted to ATP which is then used for muscle movement and other cellular metabolic processes, where the potential energy is converted to kinetic energy. Similarly the energy stored in other macromolecules is also converted to other forms but is neither created nor destroyed.

The second law of thermodynamics states that the entropy of an isolated system always increases and never decreases. When energy is lost or transfered, the entropy of the system increases. In most biological processes, when energy is converted from one form to another, some energy is lost as heat and this increases the entropy. Loss of energy at every level of food chain increases entropy, heat released during processes such as gglycolysis and photosynthesis increases entropy and so on.