expressed

Unsolved problems in biology

...tructure and function of the proteome proteins expressed by a cell or organ at a particular time and under specific conditions? What is the complete function of the regulator genes ? The building block of life may be a precursor to a generation of electronic devices and computers , but what are the ...

Stem cell

...of government Dr. Peter Lawler , all of whom have expressed a more cautionary view towards embryonic stem cell... companies and biotechnology companies initially expressed little interest because they consider therapies based on cells, which might have to be tailored to e...

Sociobiology

...e frequencies predicted by the strategy, and those expressed in a population. Measurement of genes and gene-frequencies can also be problematic, because a simple statistical correlation can be open to charges of circularity. Circularity can occur if the measurement of gene frequency indirectly uses the same ...

Signal transduction

...tivation leads to further effects, since genes are expressed as proteins , many of which are enzymes, transcription factors or other regulators of metabolic activity. Because transcription factors can activate still more genes in turn, an initial stimulus can trigger via signal transduction the expression o...

Secondary metabolite

...rganisms who produce them nor are they necessarily expressed continuously.Although plants are better known as a source of secondary metabolites, bacteria , fungi and many marine organisms (sponges, tunicates, corals, snails) are very interesting sources, too. Secondary metabolites can be classified by th...

Rudolf Steiner

...ogan, “Liberty, Equality, Fraternity,” expressed in an unconscious way the distinct needs of the three social spheres at the present time : liberty in cultural life, equality in a democratic political life, and (uncoerced) fraternity/sorority in economic life. According to Steiner, these values, ...

Blood type

...t from on red blood cells, the ABO antigen is also expressed on the glycoprotein von Willebrand factor (vWF), which participates in hemostasis (control of bleeding). In fact, blood type O predisposes very slightly to bleeding, as vWF is degraded more rapidly. Austrian scientist Karl Landsteiner was aw...

Potential energy

...nstant (a measure of the stiffness of the spring), expressed in N/m, and x is the displacement from the equilibrium position, expressed in metres (see Main Article: Elastic potential energy ) . Chemical energy Chemical energy is a...

Phylogeny

...c law, was widely accepted. This theory was often expressed as " ontogeny recapitulates phylogeny ", i.e. that the development of an organism exactly mirrors the evolutionary development of the species. The early version of this hypothesis has since been rejected as being oversimplified and misleading. Howev...

Polymerase chain reaction

...closely. Expressing a cloned gene (when a gene is expressed the gene product (usually protein or RNA ) is ...ganisms one can get a general idea of which sample expressed more of the gene of interest. A quantative RT-PCR method has been developed, it is called Real-Time...

Natural selection

... to deal with parasites. Natural selection can be expressed as the following general law (taken from the concl...n the grandfather of Charles Darwin — and he expressed much of his theory of evolution in poetic verse. His formal exposition of the hypothesis lacks a str...

Morphogenesis

... the development of a fertilized egg, but they are expressed by cells within the maternal ovary. Bicoid and ...he transcriptional regulation of other zygotically expressed proteins. Many of these are the protein products derived from members of the "gap" family of develop...

Mendelian inheritance

...ough the generations, even if the phenotype is not expressed (F 1 generations, figures 1 and 2). Figur...shape, and position of the offspring. His data was expressed numerically and subjected to statistical analysis. This method of data reporting and the large sampl...

Lambda phage

...ision of the host. The DNA of the prophage that is expressed in that state codes for proteins that look out for signs of stress in the host cell. Stress can be a result of starvation, poisons (like antibiotics), and other factors that can damage or destroy the host. At that point, the prophage becomes active...

Isozyme

...d to different functions. For example, they may be expressed at different stages of development or in different tissues. Allozymes may result from point mutations or from insertion-deletion ( indel ) events that affect the DNA coding sequence of the gene . As with any other new mutation , there are thre...

Immune system

... penetrate these barriers encounter constitutively expressed anti-microbial molecules that restrict the infecti... It was later discovered that toll-like receptors, expressed on innate immune cells, are critical in the activation of adaptive immunity. Disorders of the hum...

Glycoprotein

...r histocompatibility complex (or MHC), which are expressed on the surface of cells and interact with T-cells as part of the adaptive immune response. Other examples of glycoproteins include: components of the zona pellucida , which surrounds the oocyte , and is important for sperm -egg interaction. ...

Genomics

...zword is proteome , the totality of proteins ( expressed genes that are translated ) in an organism, tissue type or cell, and proteomics is now well-established as a term for studying the proteome. Comparative genomics Main article: Comparative genomics Comparison of genomes has resulted in so...

Gene therapy

...in — then the new gene would not be properly expressed and the cell could be made worse or even cancerous. Scientists are researching an interesting way of bypassing the DNA problems by actually introducing an extra chromosome into the body. Existing alongside existing DNA, this 47th chromosome would...

Gene

...A strands or the environment. The DNA strand is expressed into a trait only if it is transcribed to RNA . Because the transcription starts from a specific base-pair sequence (a promoter ) and stops at another (a terminator ), our DNA strand needs to be correctly placed between the two. If not, it is ...

Expressed sequence tag

An expressed sequence tag or EST is a short sub-sequence of a transcribed protein -coding or non-protein coding DNA sequence . It was originally intended as a way to identify gene transcripts , but has since been instrumental in gene discovery and sequence...

Epigenetics

... parent can result in changes in the way genes are expressed in the offspring (see Waterland citation). In bo...cludes how gene regulatory information that is not expressed in DNA sequences is transmitted from one generation (of cells or organisms) to the next - that is (h...

Enzyme

...rate of reaction is also of interest. This can be expressed by the Michaelis-Menten constant ( K M ), which...er-Burk plot. The efficiency of an enzyme can be expressed in terms of k cat / K m . The quantity k cat , also called the turnover number, incorporates t...

Morphogenesis

... the development of a fertilized egg, but they are expressed by cells within the maternal ovary. Bicoid and ...he transcriptional regulation of other zygotically expressed proteins. Many of these are the protein products derived from members of the "gap" family of develop...

Developmental biology

...ctors are the key regulators of which genes are expressed in cells. Transcriptional control in the various differentiated cell types allows each type of cell (epithelial, muscle, neuron, etc) to express different amounts of the possible proteins. The transcription factors are regulated by signal transduc...

Computed axial tomography

...sectional estimations of the radiographic density, expressed in Hounsfield units. CT is used in medicine as a diagnostic tool and as a guide for interventional procedures. Sometimes contrast materials such as intravenous iodinated contrast is used. This is useful to highlight structures such as blood ve...

Bioinformatics

... with multiple techniques including microarrays , expressed cDNA sequence tag ( EST ) sequencing, serial analysis of gene expression (SAGE) tag sequencing, massively parallel signature sequencing (MPSS), or by measuring protein concentrations with high-throughput mass spectroscopy . All of these technique...

Common descent

...ies was published. The views about common descent expressed therein vary between suggesting that there was a single "first creature" to allowing that there may have been more than one. Here are the relevant quotations from the Conclusion : "[P]robably all of the organic beings which have ever lived on this...

Chromosome

...atin , which consists of DNA that is active, e.g., expressed as protein. Heterochromatin , which consists of mostly inactive DNA. It seems to serve structural purposes during the chromosomal stages. Heterochromatin can be further distinguished into two types: Constitutive heterochromatin , which is never e...

Charles Darwin

...n's old Cambridge tutors Sedgwick and Henslow expressed their disappointment in him. Then seven liberal A...implications. He certainly agreed with views first expressed (and later retracted) by Wallace and later by his cousin Francis Galton that intelligence and pers...

Cellular respiration

...oplasm of the cell . The overall reaction can be expressed this way: Glucose + 2 NAD + + 2 ADP + 2 P i → 2 NADH + 2 pyruvate + 2 ATP + 2 H 2 O + 4 H + The individual steps of the conversion of glucose into pyruvate are (in brief): A glucose molecule from the hydrolysation of starch or glycogen...

Cell nucleus

...ute euchromatin contain genes which are frequently expressed by the cell. In heterochromatin, DNA is more tig...erochromatin generally contain genes which are not expressed by the cell (this type of heterochromatin is known as facultative heterochromatin) or are regions wh...

Full blood count

...moglobin - The amount of hemoglobin in the blood, expressed in grams per liter. (Low hemoglobin is called anemia .) Hematocrit or packed cell volume (PCV) - This is the fraction of whole blood volume that consists of red blood cells. Mean cell volume (MCV) - the average volume of the red cells, measure...

Bioinformatics

... with multiple techniques including microarrays , expressed cDNA sequence tag ( EST ) sequencing, serial analysis of gene expression (SAGE) tag sequencing, massively parallel signature sequencing (MPSS), or by measuring protein concentrations with high-throughput mass spectroscopy . All of these technique...

Barr body

... in fact a small number of genes remain active and expressed in some species. These genes are generally those which are present on the other sex chromosome (Y or W). Mechanism Mammalian X-chromosome inactivation is initiated from the X inactivation centre or Xic , usually found near the centromere . The ...

Apoptosis

...man papillomaviruses (HPV), a gene called E6 is expressed in a product that degrades p53 protein, which is...d when presented with fragments of inappropriately expressed proteins (resulting, say, from a malignant mutation) or with foreign antigen produced as a consequen...

Alternative splicing

...ed out to alter the sequence of amino acids in the expressed protein. Importance in molecular genetics Alternative splicing is of great importance for genetics it means that the old idea of one DNA sequence coding for one polypeptide (the "one-gene-one-protein" hypothesis) is no longer correct. Extern...

Allele

...als will be red. The recessive allele will only be expressed in a recessive homozygote. However, there are exc... where both alleles are active and both traits are expressed at the same time; for example, both red and white petals in the same bloom or red and white flowers ...