double

Virus

...ome , that may be either DNA or 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 helic...

Varicella zoster virus

... a hexagonal form. Its DNA is a single linear, double strand molecule, 125,000 nt long. The virus is very susceptible to disinfectants , notably sodium hypochlorite . Within the body it can be treated by a number of drugs and therapeutic agents including aciclovir , zoster immunoglobulin (ZIG), and...

T cell

...CD2,CD7 and CD3, but neither CD4 nor CD8 (they are double negative, CD4 - CD8 - cells). In the early stage...8 molecules at their surface, they are said to be double positive (CD4 + CD8 + ). Double positive cells move deeper in the cortex, where they get presente...

RNA

...se regions mark the beginning of a gene. The DNA double helix is unwound by the helicase activity of the enzyme. RNA is then synthesised so that it is complementary to one of strands in the DNA . The strand from which the RNA is encoded is called the template strand ; the opposite strand is called the...

Reverse genetics

...le organism. The discovery of gene silencing using double stranded RNA, also known as RNA interference (RNAi), and the development of gene knockdown using Morpholino oligos have made disrupting gene expression an accessable technique for many more investigators. So phenotype, rather than the starting po...

Restriction enzyme

...e through each of the phosphate backbones of the double helix without damaging the bases . The chemical bonds that the enzymes cleave can be reformed by other enzymes known as ligases , so that restriction fragments carved from different chromosomes or genes can be spliced together, provided t...

Redox

...e primarily used in the reduction of carbon-carbon double or triple bonds. The chemical way to look at redox processes is that the reductant transfers electrons to the oxidant . Thus, at the end of the reaction, the reductant will have been oxidized and the oxidant will have been reduced . This doe...

Protein biosynthesis

...ranscription only requires one strand of the DNA double helix. This is called the coding strand . The transcription starts with initiation. RNA polymerase , an enzyme, binds to a specific region on the DNA, marking the starting point, called the promoter . As the RNA polymerase binds on to the promoter...

Peptide bond

...ther by peptide bonds. The C-N bond has a partial double bond character (with the Nitrogen atom attaining a partial 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 at...

Parthenogenesis

...is means that an asexual lineage will have roughly double the rate of population growth under ideal conditions. Organisms that can reproduce through parthenogenesis are also more able to settle isolated habitats like oceanic islands, as only a single (female) member of the species has to reach the habitat t...

Redox

...e primarily used in the reduction of carbon-carbon double or triple bonds. The chemical way to look at redox processes is that the reductant transfers electrons to the oxidant . Thus, at the end of the reaction, the reductant will have been oxidized and the oxidant will have been reduced . This doe...

Lipid

... saturated fatty acids) or by both single and double bonds ( unsaturated fatty acids). The chains are usually 14-24 carbon groups long. The head groups of the phospholipids found in biological_membranes are phosphatidylcholine ( lecithin ), phosphatidylethanolamine, phosphatidylserine and phospha...

Lineweaver-Burke diagram

...iagram (also called a Lineweaver-Burke plot or double reciprocal plot ) is a graphical representation of...x-intercept of the graph represents -1/K m . The double reciprocal nature of the plot lends itself to overweighting the contribution of the least important ...

James D. Watson

... and Maurice Wilkins , they together deduced the double helix structure of DNA, which they published in the journal Nature on April 25, 1953 . Watson, Crick, and Wilkins were awarded the Nobel Prize in Physiology or Medicine for their discovery in 1962 . In 1968 Watson wrote The Double Heli...

Ploidy

... and ovum ). Diploid Diploid cells (meaning double in Greek ) have two copies ( homologs ) of each chromosome (both sex- and non-sex determining chromosomes), usually one from the mother and one from the father . Most somatic cells (body cells) of higher organisms are diploid. Haplodiploi...

Genetics

...o be DNA 1953 DNA structure is resolved to be a double helix by James D. Watson and Francis Crick 1956 Jo Hin Tjio and Albert Levan established the correct chromosome number in humans to be 46 1958 The Meselson-Stahl experiment demonstrates that DNA is semiconservatively replicated ...

Genetic recombination

... recombinase creates a nick in one strand of a DNA double helix, allowing the nicked strand to pull apart fr...ementary strand and anneal to one strand of the double helix on the opposite chromatid. A second nick allows the unannealed strand in the second double he...

Genetic fingerprinting

...NA evidence allegedly linking O. J. Simpson to a double murder. In June of 2003 , because of new DNA evidence, Dennis Halstead, John Kogut and John Restivo won a re-trial on their murder conviction. The three men had already served 18 years of their 30-plus year sentences. See also restricti...

Eukaryote

...rom such vesicles. The nucleus is surrounded by a double membrane, with pores that allow material to move i... in nearly all eukaryotes. They are surrounded by double membranes, the inner of which is folded into invaginations called cristae, where aerobic respiratio...

Enzyme

... from a limited data set, using what is known as a double reciprocal, or Lineweaver-Burk plot. The efficie...at can eliminate a group from a molecule to form a double bond and vice versa. Monoamine oxidase (MAO): oxidize certain neurotransmitters and biologicall...

Down syndrome

...le, reduced incidence of certain cancers caused by double immunity: lung cancer, for instance, is virtually unknown in people with Down syndrome. Notable individuals Notable people with Down syndrome include: Chris Burke , actor and autobiographer Down syndrome in fiction Bret Lott : "Jew...

Double helix

...nteractions, and van der Waals forces forming a double helix....

DNA

...ication is performed by splitting (unzipping) the double strand down the middle via relatively trivial chem... of molecules, which entwine like vines to form a double helix (see the illustration at the right). Each vine-like molecule is a strand of DNA: a chemi...

Ploidy

... and ovum ). Diploid Diploid cells (meaning double in Greek ) have two copies ( homologs ) of each chromosome (both sex- and non-sex determining chromosomes), usually one from the mother and one from the father . Most somatic cells (body cells) of higher organisms are diploid. Haplodiploi...

Chloroplast

...nly in plants. Both organelles are surrounded by a double membrane with an intermembrane space; both have their own DNA and are involved in energy metabolism; and both have reticulations, or many foldings, filling their inner spaces. Chloroplasts convert light energy from the sun into ATP through a proces...

Cell growth

...m a parental cell. Typical stem cells reproduce, double in size, then reproduce again. Most Cytosolic co...an cell will have 46 "double chromosomes". In each double chromosome there are two copies of that chromosome's DNA molecule. During mitosis the double chromos...

Cell nucleus

...er from 10 to 20 micrometres .It is enclosed by a double membrane called the nuclear envelope . The inner and outer membrane fuse at regular intervals, forming nuclear pores . The nuclear envelope regulates and facilitates transport between the nucleus and the cytoplasm, while separating the chemical...

Cancer

...t where the cell loses whole chromosomes , or has double ones. Also, the DNA methylation pattern of the cell changes, activating and deactivating genes more or less at random. Cells that divide at a high rate, such as epithelials , show a higher risk of becoming tumor cells than those which divide les...

Biological membrane

...ll . It is a lipid bilayer , being composed of a double layer of lipid -class molecules , specifically phospholipids , with occasional proteins intertwined, some of which function as channels . Such membranes typically define enclosed spaces or compartments in which cells may maintain a chemic...

Apoptosis

...against the nuclear envelope . At this stage, the double membrane that surrounds the nucleus still appears complete; however, as observed by Kihlmark and colleagues, specialized caspases have already advanced in the degradation of nuclear pore proteins and have begun to degrade the lamin that underlies t...