direct

Virus

...ons can be passed from host to host either through direct contact or through a vector , or carrier. Inside the organism, the virus can enter a cell in various ways. Bacteriophages —bacterial viruses—attach to the cell wall surface in specific places. Once attached, enzymes make a small hole in...

Vestibular system

...nt as directly as possible to the eyemuscles. This direct connection involves only three neurons, and is cor...ngly called Three-neuron-arc (Fig 3). Using these direct connections, eye movements lag the head movements byless than 10 ms, one of the fastest reflexes in ...

Selective serotonin reuptake inhibitor

...e of action of these antidepressant drugs on their direct target, the serotonin transport protein, and possible regulatory mechanisms with respect to long-term alleviation of depression, although having been investigated both neurobiologically and clinically over the last years, are not yet understood. N...

Signal transduction

...an react and respond to its environment. In a less direct way the same is true of animals and plants . S...ays in which Ca 2+ can regulate proteins: A direct recognition of Ca 2+ by the protein. Binding of Ca 2+ in the active center of an enzyme ...

Rudolf Steiner

...vate and|or state scholarships that a family could direct to the school of its choice. Steiner was a suppor...n in the right circumstances be researched through direct experience, by persons practicing rigorous forms of ethical and cognitive self-discipline. Steiner ...

Robert Koch

...Louis Pasteur . After Casimir Davaine showed the direct transmission of the anthrax bacillus between cows, Koch studied anthrax more closely. He invented methods to purify the bacillus from blood samples and grow pure cultures. He found that, while it could not survive outside a host for long, anthrax...

RNA

...mation of hairpin loops , coils, etc., which then direct the formation of higher-order structures. Synthesis RNA is made by an enzyme , RNA polymerase , using DNA as a template. The synthesis begins when the enzyme binds to special promoter regions on the DNA helix; these regions mark the beg...

Blood type

... parent to have a type O child (it is, however, no direct proof of illegitimacy ). Evolutionary biologists theorize that the A allele evolved earliest, followed by O and then B . This chronology accounts for the percentage of people worldwide with each blood type. It is consistent with the accepted p...

Punctuated equilibrium

...d. In the peripheral region itself, we might find direct evidence of speciation, but such good fortune would be rare indeed because the event occurs so rapidly in such a small population." An unstated supposition is that, through competition, the descendant species eliminates the ancestral species. The ...

Promoter

...s , silencers , boundary elements /insulators) to direct the level of transcription of a given gene. Pr...nal control where the promoter is believed to have direct involvement. This is a list of diseases that evidence suggests have some involvement of promoter ...

Prion

...ve idea is that prion propagation does not require direct action of a prion protein on a normal protein, but rather results from a positive feedback loop during the biosynthesis of PrP. In this view, the presence of PrP SC somehow alters the way in which PrP is synthesized, shunting it down an alternativ...

Olfaction

...rgan. Some mammals make a face called flehmen to direct air to this organ. In humans, the detection of pheromones is subliminal. These subliminal odor messages may transmit opposite immunological sexual compatibility. Finding a partner of non-similar immunological background may be evolutionarily advant...

Lytic cycle

...senger RNA (mRNA) molecules that are then used to direct the ribosome. In retroviruses , or RNA viruses, a unique enzyme called reverse transcriptase transcribes the viral RNA into DNA, which is then transcribed again into mRNA. Replication and lysis After many virus copies are made, they are assemb...

Lung

...trol air flow through the lungs, but do not play a direct role in gas exchange. They have a flow through respiration system. When a bird inhales, air flows in through the trachea to the posterior air sacs, while air currently within the lungs flows into the anterior air sacs. When the bird exhales, the fre...

Isozyme

...y more informative DNA -based approaches (such as direct DNA sequencing , Single nucleotide polymorphisms and microsatellites ), they are still amongst the quickest and cheapest marker systems to develop, and remain (as of 2005 ) an excellent choice for projects that only need to identify low levels o...

Immune system

...ctually recognize in "first person" the danger and direct the T killer attack. In this way, the innate immune system plays a critical role in the activation of the adaptive immune system. Adjuvants , or chemicals that stimulate an immune response, provide artificially this "second signal" in procedures w...

Genomics

...d from measures of DNA-DNA hybridization or from direct sequence comparisons. Species Similarity Source Human 99.9% quoted by President Clinton, Jan 2000, State of the Union address; also Human Genome Project 100% identical twins Chimpanzee 98.4% sources...

Foot and mouth disease

... virus is passed on to susceptible animals through direct contact with infected animals or with contaminated pens or vehicles used to transport livestock. The clothes and skin of animal handlers such as farmers, standing water, and uncooked food scraps and feed supplements containing infected animal produc...

Fermentation

...ally produce acids. Vinegar ( acetic acid ) is the direct result of bacterial fermentation. In milk, the acid coagulates the casein , producing curds. In pickling, the acid preserves the food from pathogenic and putrefactive bacteria. See also Industrial fermentation References Steinkraus, K....

Extinction

...to survive and becomes extinct. This may occur by direct effects, such as the environment becoming toxic ,...n that depends on dense shade for protection from direct sunlight can no longer survive with no forest to house it. Diminished resources or introduction of ...

Enzyme

...se typically bind metals or small molecules, often direct or indirect products or substrates of the reaction catalyzed. This provides a means for feedback to keep the products and substrates in proper relative abundance. As a consequence of this basic structure, the amino acid chain of an enzyme tend...

Warm-blooded

... contractions), blanching (circulatory changes to direct less heat to the skin), flushing (circulatory changes to radiate more heat from the skin), panting or sweating (to increase heat loss through evaporation ). Warm-blooded versus cold-blooded Biochemical processes are heat dependent. The rule ...

Ebola

... fever Among humans, the virus is transmitted by direct contact with infected body fluids such as blood. The cause of the index case is unknown. The incubation period of Ebola haemorrhagic fever varies from two days to four weeks. Symptoms are variable too, but the onset is usually sudden and characte...

Dialysis

...re bandaged with gauze, held for up to 1 hour with direct pressure to stop bleeding, then the taped in place. It's just like getting blood draw, only it takes a lot longer, and more fluid/Blood is lost. Temperature, standing and sitting blood pressure, and weight are all measured again. Temperature chang...

Diabetes mellitus

... . Patients with type 1 diabetes mellitus require direct injection of insulin as their bodies cannot produce enough (or even any) insulin. As of 2004, there is no other clinically available form of insulin administration other than injection for patients with type 1: injection can be done by insulin pump, ...

Blood

...ns. Treatment Blood transfusion is the most direct therapeutic use of blood. It is obtained from volunteers by blood donation . As there are different blood types , and transfusion of the incorrect blood may cause severe complications, crossmatching is done to ascertain the correct type is transfus...

Biomechanics

...nstances in which living tissue is remodeling as a direct consequence of applied loads. Contents showTocToggle("show","hide") 1 Applications 2 Continuum Mechanics 3 Biomechanics of Circulation 4 Biomechanics of the bones 5 Biomechanics of the Muscle 6 Viscoelasticity 7 No...

Biologist

... . A PhD (or equivalent) is generally required to direct independent research but a bachelor's or master's degree is sufficient for most non-research positions. Training on the undergraduate level usually is very general while later training involves a specialization in a specific area of biology . (U.S....

Barr body

...ation and histone H2A ubiquitylation , as well as direct modification of the DNA itself, via the methylation of CpG sites . These changes help inactivate gene expression on the inactive X-chromosome and to bring about its compaction to form the Barr body. See also X-inactivation Sex-determinati...

Active transport

...ndary In secondary active transport, there is no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of cells is used. The two main forms of this are counter-transport (antiport) and co-transport (symport). Counter-transport In counter-transport two...