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What is Biophysics?
Biophysics is an area of scientific study in which physical principles, physical methods, and physical instrumentation are used to study living systems or systems related to life. It overlaps broadly with biophysical chemistry, which is more specialized in scope since it is concerned with the physical study of chemically isolated substances found in living organisms. Advances in Biophysics. Advances in biophysics, like advances in physics, have come about as systems have become available for accurate study. One early branch of biophysics was the geometric optics of the eye. The character of the lens of the eye, the kind of image it makes on the retina, and the ways in which the image can be sharpened are clearly physical problems. Research in this area, which has been proceeding steadily for centuries, has provided vision correction for nearly half of mankind.
In the past, living systems did not reveal many aspects suitable for physical study. A change came about in the middle part of the 20th century with a series of discoveries: the nature of nerve impulses and muscular contraction; the operation of the retina of the eye; the molecular character of genetics; the behavior and composition of viruses; and the operation of plant chloroplast. All these systems are readily studied by physical means. Findings in these areas include the discovery that the eye can detect a single photon, the smallest possible amount of light; the elucidation of the structure of the genetic substance deoxyribonucleic acid (known as DNA); and a start on the symmetry relationships and methods of assembly of viruses.
Division of Biophysics
Roughly speaking, there are three major divisions of present-day biophysics. Perhaps the largest of these is molecular and cellular biophysics. This division is concerned with the structure and behavior of the molecular units that have been found to determine the life of the cell. Thus the structure of nucleic acids, of proteins, of lipids, and of polysaccharides (particularly as they are part of the architecture of the cell and form elements of nuclei, ribosomes, membranes, and cell walls) is of major interest to biophysicists.
The methods of study in molecular and cellular biophysics include the electron microscope; the absorption of light (selected as to wavelength); the ultracentrifuge, which subjects objects to greatly enhanced gravity and selects them for size, shape, and density; X-ray diffraction, which reveals regularities and symmetries in structure; as well as the study of the effects of physical stress such as heat and pressure.
Each of these methods is specialized and often involves many research workers. On occasion, the physical agent itself is the subject of study. One such subject is ionizing radiation, which in the form of X rays and gamma rays is either a potential benefit (X-ray diagnosis and cancer treatment) or hazard (radiation-induced leukemia), and so has a large field of biophysics devoted to itself alone.
A second area of biophysical study is physiological physics. This is the study of functional organs of a living system. These systems include vision, hearing, sensation in general, nerve action, muscular action, membrane action, and the accumulation of mineral deposits in bone, teeth, and eggs. Workers in these areas use specially designed electrical detection devices- often very elaborate ones. The electron microscope also is used, as well as specialized biochemical detectors.
A third rapidly growing area is biophysical instrumentation. As the knowledge of the functioning of living things (from parts of cells to human beings) is developing, so is the need for special instruments.
Thus, while electrocardiographs, used to study the form of the heartbeat, may be familiar to many, they represent only an early version of a whole range of instruments. These include, for example, whole-body radiation counters, which monitor the amount and kind of radioactivity accumulated by an individual; heart pacemakers, which maintain the heart beat when it is necessary to supplement the natural nerve impulses; and automatic amino-acid analyzers, which determine the composition of a protein in a matter of minutes. Background training in electronics is clearly important in this area.
Central to all areas of biophysical work is the use of radioactive isotopes, which are generated in nuclear reactors. Their use has accelerated by decades all these fields of discovery.
Training and Work in Biophysics
Training in biophysics can be obtained at the graduate level in most large universities in the United States, Canada, and the USSR. Undergraduate programs are offered in about 10 percent of the universities and colleges in the United States.
Biophysicists are valued in industries, in universities, and in medical research laboratories. The great majority then work in research laboratories at such institutions, but they are also in demand as administrators.