त्यो ब्यर्थ मुर्ति किन कुदियो?

त्यो ब्यर्थ मुर्ति किन कुदियो?
न तेसलाई आवाज भर्न सकियो
न बार्ता गर्न मिल्यो
खाली आकार दिईओ
सोखिनहरु को मोल मोलाई
को बस्तु बनाइयो

बरु ढुंगा बोक्दा कमिज च्यातियो
काध को खाला फ्याकियो
सहयोगी को हात च्यापियो
गरिखाने मान्छेलाई अपाङ्ग बनायियो
त्यो ब्यर्थ मुर्ति किन कुदियो

न तेसलाई आवाज भर्न सकियो
न बार्ता गर्न मिल्यो
खाली आकार दिईओ
सोखिनहरु को मोल मोलाई
को बस्तु बनाइयो
त्यो ब्यर्थ मुर्ति किन कुदियो?

suresh poudel
kathmandu

SCOPE AND METHODS OF BIOPHYICS

Living organisms are multilevel complex systems.Large and small molecules, cell organells, cells, tissues, organs, organisms, population, the biosphere are all levels that must be dealt with biology and biophysics.

Biophysics has been classified as:

1. Molecular Biophysics
2. Biophysics of cell
3. Biophycis of complex system

Molecular Biophysics

It is concerned with the study of the structure and physiochemical properties of biologically functional molecules; primarily biopolymers, proteins and nucleic acids. Its objective is to disclose the phycisal mechanism responsible for the biological functionality of the molecules say for catalytic activity of protein enzymes. Molecular biophycics can't be separated from molecular biology and  chemistry.
Molecular biophysics on one hand rests on biochemical disciplines and on the other hand , on the phycis of small and large molecules.


The theoritical apparatus of molecular biophysics consists of equilibrium thermodynamics, statistical mechanics and quantum mechanics. For an experimental study of biologically functional molecules use is made up of wide range of phycisal methods.

The first group includes methods employed in macromolecular physics for the determination of molecular masses, sizes and shapes- sedimentation in the ultra centrifuse, scattering of light and X-rays by collision of the substances to be studied etc.

The second group includes method used for investigarion of molecular structure and based on interaction of matter with light in the broad sense of these words from X- rays to radiofrequency radiation.NMR ( Nuclear Magnetic Resonance) and EPR( Electron Paramagnetic resonance) are also important calorimetric methods for macromolecules.

The third group includes calorimetric methods used for the study of the conversion of bioilogical macromolecules.Finally the structure of proteins and nucleic acids are directly studied by means of electron microscopy.

RELATIONSHIP BETWEEN PHYSICS AND BIOLOGY

We know biology covers all living things in the world and Physics examines the basic concpt such as energy, force space, time and all that dervices from mass, charges, matter and their motion. Broadly it is the general analysics of nature.While Bilogy is the science dealing with living organisms which are immeasurably more complicated than non living matters.

Biophysics is the application of physical laws to explan the properties of living organisms. It is the physics of life phenomena studied at all levels from molecules and cells to biosphere as a whole.

According to A.V. Hill-"Biophysics is the study of biiological function, organisation and structure of physical and physiochemical ideas and method."

According to vital force theory-Biological phenomena are basically incompressible on the basis of phsics and chemistry. Since there exists a certain mysterious vital forece or biological field which are not amenable to a physical interpretation.

The first law of thermodynamics tells conservation of energy was based on the observation of living organisms. According to uncertainity princliple the physio-chemical properties of living organism and life phenomena cant be studied. Simultaneously physiochemical and biological investibation are complementary to each other.

Schrodinger gave the concept of thermodynamical foundation of life. He stated that the living organisms"feed on negative entropies ie. the living organisms and the biosphere as a whole are not isolatedc but open system which exchange both matter and energy with the outisde world. He posed the question of stability of the substance of genes which is made up of light atoms; C, H, N,O.

Still the modern physics is not approching its limits of applicability for the treatment of biological phenomena but it points to the unlimited possibilities.

The living systems are basically open and therefore non equilibrium. A living organism is a thermodynamically open system which undergoes chemical reactions.Biochemical reactions are catalytic at all stages and protein-enzymes serve as catalyst. The change in entropy of such system is expressed by the sum  of the entropy produced inside the system  dis and the entropy supplied externally or given off the surrounding des
                                                                   ds =d is - d es

The quantity dis  is always positive according to the second law of thermodynamics. If the organism is placed in an insulating shell, the entropy flow des    will be equal to zero and the entropy can only incerease . The entropy of the system is not at the maximum. For the stationary state, we have 

                                                                                 ds = 0             ie. des = - dis <0   


In other words, the entropy produced is given up completely to the surrouonding.