Question

A lady asked a doctor why she is enable to lose weight though she takes care of diet and exercise. Out of joke, the doctor said, ˝Law of conservation of mass hold good as if you will lose weight, someone else will gain weight.‖ However, it was all fun as law of thermodynamics really does not work that way. Laws of thermodynamics help us to understand some of the biological processes occurring in our body.

Now answer the following questions.

(i) Why sometimes we are not able to lose weight inspite of proper diet and regular exercise? Explain in terms of first law of thermodynamics.

(ii) How doesn't the concept of entropy (a measure of randomness) used in thermodynamics explain the ***** of cell if we do not eat food?

Answer 1

(i) No doubt, to manage our weight, calories in should be equal to calories out, i.e., there has to be balancing between calories eaten and calories burnt. The first law of thermodynamics deals with the energy balanced but applies to a closed system. Human body is not of a closed system but an open system. In real life, balancing energy includes a lot more than just the calories we eat and calories we **. This is because some calories are stored as * and as glucose in lever and calories are also used in growth, tissue restoration and number of metabolic process. Thus, calories eaten and calories used in exercise and work are only two small parts of energy balance and hence meaningless unless all others variables are controlled which they can never be as they are not under our control.

(ii) Food gives heat energy to the cell. As environment is at lower temperature the cell lose their heat to the environment. By losing heat energy, we (our cells) in effect lower our entropy. If the cell fails to obtained its entropy increases indefinitely leading to the destruction of its highly ordered low entropy structure leading to the cell (our organism) *****.