Biophysics

Biophysics, an abbreviation of biological physics, is the integration and application of the principles of physics to explain and explore the form and function of living things. The most familiar examples of the role of physics in biology are the use of lenses to correct visual defects and the use of x rays to reveal the structure of bones. Principles of physics have been used to explain some of the most basic processes in biology such as osmosis, diffusion of gases, and the function of the lens of the eye in focusing light on the retina.

The study and research in biophysics uses such interdisciplinary scientific fields as biology (such as biochemistry, genetics, molecular biology, microbiology, structural biology, and virology), chemistry (such as computational chemistry and physical chemistry), computer science, genetics, mathematics (such as mathematical modeling), medicine, pharmacology, physiology, physics (such as quantum mechanics), and neuroscience. The science of biophysics developed as a result of World War II (1939–1945). The nuclear weapons program initiated during the war was applied to biological systems such as the effects radiation would have on living organisms. Such research led to the formation of the field of biophysics after the war.

The understanding that living organisms obey the laws of physics as non-living systems do has had profound effects on the study of biology. The discovery of the relationship between electricity and muscle contraction by Italian physician and physicist Luigi Galvani (1737–1798) initiated a field of research that had continued to give information about the nature of muscle contraction and nerve impulses. It has led to the development of such instruments and devises as the electrocardiograph, electroencephalograph, and cardiac pacemaker. Medical technology in particular has benefited from the association of physics and biology. Medical imaging with 3-D (three-dimensional) diagnostic techniques such as computer tomographic (CAT) scanning, magnetic resonance imaging (MRI) and positron emission tomography (PET) have permitted researchers to look inside living things without disrupting life processes. Today, lasers and x rays are routinely used in medical treatments.

The use of non-invasive imaging traces it roots to advances in the understanding of the fundamentals and biophysical interactions of electromagnetism during the nineteenth century. By 1900, German physicist Wilhelm Konrad Röntgen’s (1845–1923) discovery of high energy electromagnetic radiation in the form of x rays found use in medical diagnosis. Developments in radiology progressed throughout the first half of the twentieth century, finding extensive use in the treatment of soldiers during World War II.

Although nuclear medicine—heavily based upon advances in biophysics—traces its clinical origins to the 1930s, the invention of the scintillation camera in the 1950s brought nuclear medical imaging to the forefront of diagnostics.

The use of a wide array of instruments and techniques, which was furthered by discoveries in physics, especially electronics, has helped biology to change from a descriptive science to an analytical one. An example of this advancement is one of the most important events of the twentieth century: the deciphering the structure of the DNA (deoxyribonucleic acid) molecule using x-ray diffraction. The technique has also been used to determine the structure of hemoglobin, viruses, and a variety of other biological molecules and microorganisms. The ability to apply information discovered in physics to the study of living things led to the development and use of the electron microscope and ultracentrifuge, instruments that have revealed much information about cell structure and function. Other applications have been sensors for heat and pressure detection that give information about body functions under a variety of conditions which have been of great importance in the space program.

The development of biophysics was also helped along by the study of how information is transmitted within the human body and in other animals. Impulses within nerve cells transmit information. This activity was not well understood until scientists researched the area with mathematical modeling methods, electronics such as computers, and electrochemistry. Today, biophysics is involved, for instance, with nanotechnology, the study and development of technologies at the scale of a nanometer (or one-billionth the length of one meter). Quantum physics (theoretical physics at the atomic and subatomic levels) has been used in such studies, which gives an idea just how far biophysics has developed since its beginning in World War II.

See also Computerized axial tomography; Laser; Microscopy; Nanotechnology.

Biophysics

Biophysics is the application of the principles of physics (the science that deals with matter and energy) to explain and explore the form and function of living things. The most familiar examples of the role of physics in biology are the use of lenses to correct visual defects and the use of X rays to reveal the structure of bones.

Words to Know

Computerized axial tomography (CAT scan): An X-ray technique in which a three-dimensional image of a body part is put together by computer using a series of X-ray pictures taken from different angles along a straight line.

Electron microscope: A microscope that uses a beam of electrons to produce an image at very high magnification.

Laser: A device that uses the movement of atoms and molecules to produce intense light with a precisely defined wavelength.

Magnetic resonance imaging (MRI): A technique for producing computerized three-dimensional images of tissues inside the body using radio waves.

Positron-emission tomography: A technique that involves the injection of radioactive dye into the body to produce three-dimensional images of the internal tissues or organs being studied.

Ultracentrifuge: A machine that spins at an extremely high rate of speed and that is used to separate tiny particles out of solution, especially to determine their size.

X ray: A form of electromagnetic radiation with an extremely short wavelength that is produced by bombarding a metallic target with electrons in a vacuum.

X-ray diffraction: A technique for studying a crystal in which X rays directed at it are scattered, with the resulting pattern providing information about the crystal's structure.

Principles of physics have been used to explain some of the most basic processes in biology such as osmosis, diffusion of gases, and the function of the lens of the eye in focusing light on the retina. (Osmosis is the movement of water across a membrane from a region of higher concentration of water to an area of lower concentration of water. Diffusion of gases is the random motion of gas particles that results in their movement from a region of higher concentration to one of lower concentration.)

The understanding that living organisms obey the laws of physics—just as nonliving systems do—has had a profound influence on the study of biology. The discovery of the relationship between electricity and muscle contraction by Luigi Galvani (1737–1798), an Italian physician, initiated a field of research that continues to give information about the nature of muscle contraction and nerve impulses. Galvani's discovery led to the development of such instruments and devices as the electrocardiograph (to record the electrical impulses that occur during heartbeats), electroencephalograph (to record brain waves), and cardiac pacemaker (to maintain normal heart rhythm).

Medical technology in particular has benefited from the association of physics and biology. Medical imaging with three-dimensional diagnostic techniques such as computerized axial tomography (CAT) scanning, magnetic resonance imaging (MRI), and positron-emission tomography (PET) has permitted researchers to look inside living things without disrupting life processes. Today, lasers and X rays are used routinely in medical treatments.

The use of a wide array of instruments and techniques in biological studies has been advanced by discoveries in physics, especially electronics. This has helped biology to change from a science that describes the vital processes of organisms to one that analyzes them. For example, one of the most important events of this century—determining the structure of the DNA molecule—was accomplished using X-ray diffraction. This technique has also been used to determine the structure of hemoglobin, viruses, and a variety of other biological molecules and microorganisms.

The ability to apply information discovered in physics to the study of living things led to the development of the electron microscope and ultracentrifuge, instruments that have revealed important information about cell structure and function. Other applications include the use of heat and pressure sensors to obtain information about bodily functions under a variety of conditions. This application of the principles of physics to biology has been of great value in the space program.

[See also Laser; Physics; X rays ]

Biophysics

Biophysics is the integration and application of the principles of physics to explain and explore the form and function of living things. The most familiar examples of the role of physics in biology are the use of lenses to correct visual defects and the use of x rays to reveal the structure of bones. Principles of physics have been used to explain some of the most basic processes in biology such as osmosis , diffusion of gases, and the function of the lens of the eye in focusing light on the retina.

The understanding that living organisms obey the laws of physics as non-living systems do has had profound effects on the study of biology. The discovery of the relationship between electricity and muscle contraction by Luigi Galvani, an eighteenth-century physician, initiated a field of research that had continued to give information about the nature of muscle contraction and nerve impulses. It has led to the development of such instruments and devises as the electrocardiograph, electroencephalograph, and cardiac pacemaker . Medical technology in particular has benefited from the association of physics and biology. Medical imaging with 3-D diagnostic techniques such as computer tomographic (CAT) scanning, magnetic resonance imaging and positron emission tomography have permitted researchers to look inside living things without disrupting life processes. Today, lasers and x rays are routinely used in medical treatments.

The use of non-invasive imaging traces it roots to advances in the understanding of the fundamentals and biophysical interactions of electromagnetism during the nineteenth century. By 1900, physicist Wilhelm Konrad Roentgen's (1845–1923) discovery of high energy electromagnetic radiation in the form of x rays found use in medical diagnosis . Developments in radiology progressed throughout the first half of the twentieth century, finding extensive use in the treatment of soldiers during World War II.

Although nuclear medicine—heavily based upon advances in biophysics—traces its clinical origins to the 1930s, the invention of the scintillation camera in the 1950s brought nuclear medical imaging to the forefront of diagnostics.

The use of a wide array of instruments and techniques futhered by discoveries in physics, especially electronics , has helped biology to change from a descriptive science to an analytical one. An example of this is one of the most important events of this century, deciphering the structure of the DNA molecule using x-ray diffraction , a technique which has also been used to determine the structure of hemoglobin, viruses, and a variety of other biological molecules and microorganisms . The ability to apply information discovered in physics to the study of living things led to the development and use of the electron microscope and ultracentrifuge , instruments that have revealed much information about cell structure and function. Other applications have been sensors for heat and pressure detection that give information about body functions under a variety of conditions which have been of great importance in the space program.

See also Computerized axial tomography; Laser; Microscopy; Nanotechnology.

bi·o·phys·ics / ˌbīōˈfiziks/ • pl. n. [treated as sing.] the science of the application of the laws of physics to biological phenomena.DERIVATIVES: bi·o·phys·i·cal / -ˈfizikəl/ adj.bi·o·phys·i·cist / -ˈfizəsist/ n.

biophysics Study of biological phenomena in terms of the laws and techniques of physics. Techniques include X-ray diffraction and spectroscopy (the measurement of spectrums). Subjects studied include the structure and function of molecules, the conduction of electricity by nerves, the visual mechanism, the transport of molecules across cell membranes, muscle contraction (using electron microscopy) and energy transformations in living organisms.