Integrated Principles of Zoology Study Set 3

Biology

Quiz 4 :
Cellular Metabolism

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Quiz 4 :
Cellular Metabolism

The first law of thermodynamics states that "energy cannot be created nor destroyed but it can be converted from one form to another". The second law of thermodynamics states that "closed system moves toward increasing disorder, or entropy". Living systems appear to violate the second law of thermodynamics because living things maintain a high degree of organization despite a universal trend toward increasing disorganization. Living systems are not closed but open systems which utilize the energy in the environment to make themselves more organized. However after death of the living system, the second law of thermodynamics is followed and entropy occurs.

The free energy in a system is the energy available for doing work. A reaction that proceeds spontaneously will have a positive change in the free energy and such reactions are called as exergonic reactions.

In many biochemical reactions energy barrier to the reaction must be lowered in order to continue the reaction. This is accomplished by the chemical substances known as catalysts. They are helpful in reducing activation energy and accelerating the chemical reaction. Enzymes are the biological catalysts that are used in the living world to carry out many biochemical reactions at a faster rate.

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