negative

Virus

...r RNA , single or double stranded and positive or negative sense. This is surrounded (encapsidated) by a protective coat of protein called the capsid . The viral capsid may be either spherical or helical and is composed of proteins encoded by the viral genome. In helical viruses, the capsid protein (fr...

Virus classification

...ed RNA) Order Mononegavirales (non-segmented negative stranded viruses) Family Bornaviridae - Bor...abdoviridae - e.g. Rabies virus Segmented negative stranded viruses Family Arenaviridae Family Bunyaviridae - e.g. Hantavirus Family O...

T cell

...ause autoimmune diseases). This process is called negative selection . T cells go into apoptosis if they can...en't positively selected or if they get removed by negative selection. About 98% of T cells die in the thymus. Their remains get engulfed by macrophages. Only ...

Stem cell

...m cells, the tests were able to avoid triggering a negative bodily reaction, which are common in other transplantations, according to Hoon Han , one of the researchers. "We don’t need a strict match between cord blood stem cell type and the immune system of a patient because the latter accepts the for...

Blood type

...ant, as mismatching (an Rh positive donor to an Rh negative recipient) will cause hemolysis . The converse is...eact to Rh- blood. Rh disease occurs when an Rh negative mother who has already had an Rh positive child (or an accidental Rh+ blood transfusion) carries ano...

Punctuated equilibrium

...times referred to by the slang "punk eek," with no negative connotations implied.) The actual differences between the various evolution theorists were not as large as they were made to appear. Gould himself later said that the theory did not in fact refute Darwin's gradualism, it just added the ideas of cat...

Potential energy

...nite distance r from a source of gravitation has negative potential energy. If the source is approximated as a point mass , the potential energy simplifies to: See also Gravitational binding energy . Elastic potential energy This energy is stored as the result of a deformed solid such as a stret...

Phloem

... water and minerals through the xylem is driven by negative pressures (tension) most of the time, movement through the phloem is driven by positive hydrostatic pressures . This process is termed translocation , and is accomplished by a process called phloem loading and unloading . Cells in a sugar source...

Peptide bond

...tial positive charge and the oxygen atom a partial negative charge) and the molecule can normally not rotate around this bond. The whole arrangement of the four C,O,N,H atoms as well as the two attached carbons in a peptide bond is planar. A peptide bond can be broken by amide hydrolysis (the adding of wat...

Natural selection

...on evolution Fitness genetic drift negative selection selection sexual selection survival of the fittest External links Introduction to evolutionary biology (has a section on natural selection in context of evolution) Darwin's Precursors and Influences. Part 4 -- Nat...

Magnetic resonance imaging

...ost universally dropped. This is done to avoid the negative connotations of the word nuclear , and to prevent patients from associating the examination with radiation exposure. Scientists still use NMR when discussing non-medical devices operating on the same principles. Technique Medical MRI...

Malaria

... for use in many countries in the 1970s due to its negative environmental impact. There is great controversy regarding this impact and the use of DDT to fight human diseases. Some claim that the ban is responsible for malaria deaths counted in tens of millions in tropical countries where the disease had been ...

Life

...d, protein readout system "a system of inferior negative feedbacks subordinated to a superior positive feedback " ( J. theor Biol. 2001 ) Tom Kinch's definition of life as a highly organized auto-cannibalizing system naturally emerging from conditions common on planetary bodies, and consisting of a popul...

Kidney

...alamus , which notifies the pituitary gland via negative feedback . The pituitary gland secretes antidiuretic hormone, otherwise known as vasopressin (or stops the secretion if water is in excess), which causes a change in the water absorption of the kidney tubule. Tissue fluid concentration thus retur...

Ion channel

... pore -forming proteins help establish the small negative voltage that all cells possess at rest (see cell potential ). Contents showTocToggle("show","hide") 1 Basic features 2 Biological role 2.1 Diversity and activation 3 Detailed structure 4 History 5 See also 6...

Hormone

...d by a homeostatic control system, generally by negative feedback . Homeostatic regulation of hormones depends, apart from production, on the metabolism and excretion of hormones. Hormone secretion can be stimulated and inhibited by: Other hormones ( stimulating or releasing -hormones) Plasma con...

Human

...s, both positive (such as love or ecstasy ) and negative (such as jealousy ). (See also Libido .) Body The physical appearance of the human body is central to culture and art . In every human culture, people adorn their bodies, with tattoos , cosmetics , clothing , and jewelry . Hairstyles ...

Homeostasis

...is less common in naturally occurring systems than negative feedback, but it has its applications. For example, in nerves , a threshold electric potential triggers the generation of a much larger action potential . (See also leverage points .) Ecological homeostasis In the Gaia hypothesis , Ja...

HACEK organism

...EK organism is one of a set of slow-growing Gram negative bacteria that form a normal part of the human flora . They are a frequent cause of inflammation of the inner layer of the heart, ( endocarditis ) in children . The name is formed from their initials: H aemophilus aphrophilus and Haemophi...

Gel electrophoresis

...of nucleic acids, the direction of migration, from negative to positive electrodes, is due to the natural negative charge carried on their sugar - phosphate backbone. Double-stranded DNA fragments natually behave...

Enzyme

...by enzymes must be 'spontaneous' (containing a net negative Gibbs free energy ), i.e. with the enzyme, they...tetrahydrofolic acid DNA gyrase : catalyzes the negative supercoiling of prokaryotic DNA Glutamate decarboxylase : synthesizes the neurotransmitter GABA ...

Gel electrophoresis

...of nucleic acids, the direction of migration, from negative to positive electrodes, is due to the natural negative charge carried on their sugar - phosphate backbone. Double-stranded DNA fragments natually behave...

Dynein

...oplasmic dynein is implicated in moving toward the negative end of a microtubule. See also: Kinesin External links How Cilia and Flagella Work (axonemal dynein) Microtubule Based Movement (cytoplasmic dynein)...

Charles Darwin

...society could potentially affect these traits in a negative fashion. He also clearly had a certain disdain for... he wrote. For each tendency of society to produce negative selections, Darwin also saw the possibility of society to itself check these problems, but also note...

Avian influenza

...nounced that seven Vietnamese who initially tested negative for bird flu were later found to have carried the virus. All seven have since recovered from the disease. Antiviral drugs are sometimes effective in both preventing and treating the disease, but no virus has ever been really cured in medica...

ATP synthase

...be seen in the transmission electron microscope by negative staining (1962, Fernandez-Moran et al., Journal of Molecular Biology, Vol 22, p 63). These are particles of 9 nm diameter that pepper the inner mitochondrial membrane. They were originally called elementary particles and were thought to contain the e...

Arabidopsis

... the absence of gravitropic action have shown both negative phototropic response to blue or white light, and positive phototropic response to red light. The photosensitive pigments phytochrome A and phytochrome B mediate this red light based phototropic response. Common names include Thale Cress, Mouse-ear C...

Apoptosis

...comprises a complex interplay between positive and negative regulators Apoptotic process Morphology A cell undergoing apoptosis shows a characteristic morphology that can be seen under a microscope : The cell becomes round (circular). This occurs because the protein structures that conform the ...

Amino acid

...0.46 Amino Acid hydrophobic positive negative polar charged small tiny aromatic aliphatic van der Waals volume Ala X - - - - X X - - 67 Cys X - - - - X - - - 86 Asp - - X X X X - - - 91 Glu - - X ...

Amine

...rnary ammonium cation will be formed along with a negative halide ion. These sort of paired ion compounds are called quaternary ammonium salts . The X shown in the above reactions can also be some other leaving group forming a corresponding acid or anion. Because inversion of the three substituen...

Alpha helix

...ildup of positive charge at the N-terminal end and negative charge at the C-terminal end which is a destabilizing influence. As a result, α helices are often capped at the N-terminal end by a negatively charged amino acid (like glutamic acid ) in order to stabilise the helix dipole. Less common (and ...