Answer to Question #302810 in Cell Biology for Amber

Question

If the law of thermodynamics is true in biological system, prove it.

Answer 1

1st Law of Thermodynamics - Energy cannot be created or destroyed. 

2nd Law of Thermodynamics - For a spontaneous process, the entropy of the universe increases. 3rd Law of Thermodynamics - A perfect crystal at zero Kelvin has zero entropy.

Explanation according to the first law of Thermodynamics.

All living organism require a certain amount of energy to survive. In system where all the parameters are kept constant such as the universe, this energy will be transferred from one form to another. In living organisms, the cells perform a vital process which require energy for its normal running. During photosynthesis, the sun is the main source of energy to the plants. The light energy will then be absorbed by the cells in the leaves and later converted to chemical energy. This energy is then stored in glucose and when needed, it can be released through cellular respiration thus plants can access it. This energy can be accessed by plants inform of carbohydrates, lipids and other macromolecules through production of adenosine triphosphate. The plants will use this energy to perform various cells functions such as, mitosis, meiosis, DNA replication, cell movement, endocytosis and apoptosis.

 

2nd Law of Thermodynamics - For a spontaneous process, the entropy of the universe increases.

During the biological process, the transfer of energy to the next form is not 100% effective as expected. During photosynthesis process, all the light energy is not effectively absorbed by the plants, some of the light energy will be reflected while some will be lost as heat to the immediate surroundings. The loss of energy to the surrounding will result in the increase of entropy. The top organism in the food chain tend to receive less energy from its food due to loss of heat to the surrounding and other factors. Most of this energy is lost due to the metallic process by the producers and primary consumers that are eaten.