This discovery started the process of clarifying the molecular basis of genetics. It also established the central dogma that dna determines the sequence of rna, which in turn governs protein synthesis, even though exceptions to this rule were found later. Her experiments were made possible by the application of X-ray crystallography to defining protein structure. Perutz used this technique to. Once it was realized that the sequence of dna bases is the genetic language it became necessary to devise methods for reading these sequences. He also elucidated some of the ways in which dna repairs mistakes liable to give rise to harmful mutations, a vital defense against the potentially disastrous effects of uv irradiation and other mutagenic agents.
Indeed his work suggested the possibility that the earliest life forms on Earth may have been solely rna dependent. Advances in genetics were accompanied by experiments in genetic manipulation using viruses called bacteriophages phage which infect bacteria.
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The interactions between phage and bacteria proved a vitally important model for understanding gene function and also the mechanisms which control gene activation and expression. Exploitation of this system marked the origins of what is now termed molecular biology. The findings in this model have proved broadly applicable to all other living species. They analyzed the interactions between phage and bacterial genes to formulate the general principles which determine the activation of some genes to initiate cellular events and other "repressor" genes which control activated genes.
The isolation and study of defined dna sequences was advanced by the discovery of enzymes by Daniel Nathans termed "restriction enzymes" which reproducibly cut dna into manageable segments for analysis. Another vital step in the development of genetic manipulation was Sol Spiegelman's discovery that rna sequences stick specifically to the dna sequences from which the rna was transcribed, a process termed hybridization.
He was also one of the first scientists to appreciate that a powerful method of discovering the function of a gene is to induce a deliberate mutation which will thereby cause the damaged dna sequence to malfunction. Gene activation and repression is also an essential process in normal embryonic development. These studies helped to establish the principle that the origin of human diseases can be investigated by detecting mutant genes and the abnormal proteins these genes encode. Elucidating the mechanisms of molecular genetics led to a greatly improved understanding of viral replication in cells and known viral infections.
The new techniques also disclosed a viral cause for many diseases of previously unknown origin. Furthermore the longstanding suspicion that viruses may play a role in cancer and many chronic diseases is now open to rational investigation. Aaron Shatkin and Seymour S. Without this discovery the nature of aids and other retroviral infections could not have been rationally investigated.
The history of research on "viral" infections continues to be unpredictable and a field where yesterday's heresy becomes a new orthodoxy. Cells have proved to be mini-organisms of great complexity and one can only discuss those fields of research on cell biology to which Jewish biologists have made especially significant contributions.
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Most tissues consist of self-renewing cells; their life cycles and the factors which regulate these cycles are of great basic interest and medical relevance. Marc Kirschner's work has helped to understand the signal pathways which induce cell division. The cell interior contains a complex network of channels and associated structures for the transport, processing, and degradation of proteins and other complex molecules imported into the cell or exported as the products of specialized cells. The findings of James Rothman and Randy Schekman have helped to clarify the structure and function of the most important of these cellular components.
Another area of current basic and potential clinical interest is the identification and propagation of stem cells with full or limited potential to mature into specialized cells. It has also become apparent that cell division and maturation depend on the actions of growth factors produced by many cell types in a complex, interdependent manner.
Cohen later discovered epidermal growth factor. These factors are now collectively termed "cytokines. Cell membranes, their receptors, and the signals these receive largely govern the behavior of cells and organs. There is a consistent record of major contributions by Jewish scientists to characterizing the biochemical pathways which provide energy and govern other metabolic processes. Modern biochemistry has revealed a myriad biochemical processes other than the classical metabolic pathways.
Two examples serve to illustrate specialized fields in the life sciences in which Jewish scientists have been especially prominent. Working out how each of the one hundred billion nerve cells in the brain communicates with one thousand other nerve cells is an enduring, largely unsolved challenge. The mechanisms of drug action on the brain are of practical importance, an area greatly illuminated by Hans Kosterlitz's studies in the field of natural opiate substances produced by the brain and the receptors on which these act. The special senses pose different questions.
Simply stated, the central problem in immunology is to understand how the body rapidly generates molecules which combine specifically with the distinctive, mainly protein antigens expressed by infectious agents while avoiding autoimmune reactions with its own tissues.
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This advance has had momentous implications for the diagnosis and treatment of immunological and other diseases, for laboratory diagnosis and for biotechnology. This control is largely determined by surface structures termed histocompatibility antigens in general and the hla system in man which are expressed primarily by cells engaged in immune responses. The first recognition that certain human diseases result from autoimmunity came from the work of Noel Rose, Deborah Doniach, and Ivan Roitt.
Modern times have witnessed a loss of any inhibitions by Jewish scientists about discussing the origins of life on Earth. This has expanded into exobiology, the possibility that life exists elsewhere in the universe. Sol Spiegel and Leslie Orgel have proposed that self-replicating rna was the primordial molecule in all life forms. Sidney Fox argued that amino acids, the building blocks of proteins, became self organized into replicating microspheres, an idea for which Stanley Miller has provided experimental support.
A more general theory advanced by Stuart Kauffman is that randomly associating molecules in the correct chemical medium of the primitive Earth became autocatalytic and matured into living forms on a random basis. The subject has matured into a respectable topic for debate in scientific and religious circles. The success of Jewish scientists in the life sciences as in other branches of science reflects a logical extension of traditional Jewish reverence for learning.
However, this success has not been achieved by ignoring other aspects of Jewish learning and enterprise. An analysis of their careers shows that many have continued to support Jewish communal activities and even more have identified with Israel in general or have forged links with Israeli academic institutions. Indeed traditional scholarship and scientific discovery have been mutually supportive. To me it's holy writ and it should be an achievement that cannot be altered" Joshua Lederberg , Cite this article Pick a style below, and copy the text for your bibliography.
Denman, Michael " Life Sciences. Denman, Michael "Life Sciences. September 24, Retrieved September 24, from Encyclopedia.
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Then, copy and paste the text into your bibliography or works cited list. Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia. The life sciences, defined as biology and related subjects, encompass the detailed study of living organisms, which are broadly distinguished from inorganic matter through the capacity for growth, function, and change preceding death.
Biology is not limited to physiology, the study of the growth and function of living organisms. It also includes the study of biochemical reactions taking place in particular cells of particular organs. At a physical level, biophysics considers, for example, electrical changes taking place across membranes. Even more specific is the field of molecular biology , which attempts to unravel the changes that occur in molecules during biochemical reactions. Genetic science is the study of molecules that act as templates of information for certain biochemical reactions and that are passed on to the next generation.
Yet the life sciences include the study of more than just the interior of living organisms and the biological reactions in the cells of living organisms. The life sciences also include ecology, the study of the exterior context of particular environments and the interrelationships between species. More broadly, animal behaviorists examine the way animals react to environments, and psychologists explore the possible reasons for this behavior.
The different life sciences pose challenges to theological and religious interpretations of reality. Put simply, if the life sciences can offer explanations for the way life functions on Earth , there is no need to invoke a divine creator. Is it possible to recover the belief held in the seventeenth century that all aspects of creation are the works of a divine mind? Or, if one accepts that God creates the world through the processes of biology, how far might it be possible to take such knowledge into human hands?
Use the link below to share a full-text version of this article with your friends and colleagues. Learn more. Germination provides many potentially unrecognized sources of variation in the regeneration niche. We found that, whereas increased duration of direct irradiance can be an effective indicator of the presence of a canopy gap across all scales of canopy openness, diel fluctuations in soil temperature effectively discriminate both understory sites and small gaps 25 m 2 from larger gaps.
Germination response was significantly related to seed size. The maximum seed burial depth from which seedlings could emerge successfully was strongly positively associated with seed mass. Therefore, seed size differences constrain the physiological mechanisms of canopy gap detection in tropical pioneer trees and might contribute to observed differences in the distribution of adult plants in relation to canopy gap size.
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Using electron microscopy, combined with fractionation techniques she was a pioneer in identifying and characterizing the major antenna systems in red algae and cyanobacteria. In continuing with her interest of phycobiliproteins as photosynthetic antennae, she and collaborators demonstrated that in cryptophyte algae, phycobiliproteins occurred within the thylakoid lumens and not as discreet bodies as in cyanobacteria and red algae Gantt et al. Beth established her own laboratory located initially in the basement of the Smithsonian Castle on the National Mall.
By , the laboratory space and equipment were enhanced after a move to a new building in Rockville, Maryland. During the 20 plus years at the RBL, her laboratory made several seminal advances. First, she isolated and purified phycobilisomes and showed the phycobiliproteins consisted of several pigments with different spectral properties; second, her laboratory was able to isolate intact phycobilisome-thylakoid preparations that were active in light-driven electron transport.
Beth also developed productive collaborations with scientists from Japan and Israel.
Thus, she and coworkers demonstrated that phycobiliproteins served as antenna pigments that captured light energy and passed them in sequence to other pigments excited at longer wavelengths to jump start photosynthetic oxidation at Photosystem II. The unique architecture of phycobilisomes from cyanobacteria and red algae allowed this elegant demonstration of how light energy is captured and transferred to begin photosynthesis. This fundamental concept is widely applicable to all plants and was highlighted in the Plant Physiology textbook Salisbury and Ross, After an open search, Beth was appointed as Professor of Plant Biology at the University of Maryland at College Park in , where she had already served as Adjunct Professor since When Beth entered academia for the first time as a senior faculty, she dived into her new role wholeheartedly and energetically as if she wanted to make up for lost time.
She demonstrated a commitment to teaching and a strong sense of responsibility to service that is rarely seen. These classes had students per semester. Furthermore, she took on heavy-duty administrative and leadership roles, including Director of Graduate Studies in Plant Biology for 4 years, and later as Director of Graduate Studies in Molecular and Cellular Biology, a new interdepartmental program. Beth also stepped up to the plate as Acting Chair of the Botany Department when the college was undergoing reorganization.
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