|
Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> A DNA Abundant mRNAs
|
|
A-DNA
A right-handed duplex DNA structure seen in microcrystals in which most of the water is removed. It has approximately 11 base paris per turn of the helix with a pitch of 28Å. The A form of DNA is seen in double-stranded RNA and in DNA/RNA hybrids. The A-form is shorter and has a greater diameter compared to the B form. The sugar rings are parallel to the helix axis and the phosphate groups are on the outside of a cylinder of 24Å diameter. The furanose ring has C3’ endo pucker and the glycoside is in the anti conformation. |
The distance between adjacent bases (rise) is 0.256nm (2.56Å). There are 11 base paris/turn of the helix giving a pitch of 2.8nm or 28Å. The stacked bases are tilted sideways through 20 Å in order to maintain normal van der Waals separation of 3.4Å
A-DNA
A-site see aminoacyl site
|
Abetalipoproteinaemia A rate disorder in which the synthesis of chylomicrons, LDL and VLDL is impaired due to a defect in the formation of apo B. As a consequence, the transport of lipids form the intestine or liver is affected with accumulation of acylglycerols in these tissues. The plasma levels of cholesterol and triglycerides are very low. The clinical manifestations include malasorption of fat (steatorrhoea) neuropathy and thorny red cells (acanthocytosis)
Abiotic stress the harmful effect of non-living factors (drough, extreme temperatures, pollutants, etc)
ABO blood group A system of grouping human blood types into A, B, AB or O group based on the antigen(s) expressed at the surface of human erythrocytes.Individuals with blood group A contain anti-B antibodies in the blood and type O individuals neither. The ABO system contains 100 different antigens and is of medical significance with respect to blood transfusion, as well as to establish paternity. While individuals with type AB blood group are considered as universal acceptors. O group individuals are universal donors. Incompatible blood transfusions can cause haemolysis
|
|
Abortive transduction The process by which linear DNA remaining in the cytoplasm is degraded or become stabilised in the cytoplasm. Under such circumstances, the transduced genes may be expressed but cannot be replicated because they lack an ori of replication
Abscess Collection of pus in a cavity
Abscisic acid A plant hormone synthesised by wilting leaves that counteracts the effects of other hormones by inhibiting cell growth and division, seed germination and building, and by inducing dormancy
Absciss; abscissa The horizontal axis of a graph
|
|
|
Absolute configuration The configuration of the four different substituents around an asymmetric carbon in relation to D-and L-glyceraldehyde
Absorb To take in or suck up in the cell substances are taken in form a solution
Absorbance A unit of the amount of light absorbed by a solution or by a bacterial suspension. It is a logarithmic function of the percentage of transmission of a particular wavelength of light through a liquid. Absorbance is measured using a colorimeter or spectrophotometer and is used to determine the concentration of molecules in solution. Also known as optical denisty
|
Absorption The Process of absorbing; taking up of water and nutrients by assimilation or imbibition. Taking up by capillary, osmotic, chemical or solvent action, such as the taking up of a liquid by a solid or of a glass by a solid or liquid. 1 in biology, refers to the movements of a fluid or a dissolved substance across a cell membrance 2. in plants, describes the taking up of water and mineral salts form the soil by roots 3. in animals, refers to absorption of solubilised food materials into the circulatory system through cells lining the alimentary canal. 4 In virology, the entry of the viral genome into the host cell after absorption of the virus to the cell surface 5 in photometry, a light that is neither reflected nor transmitted is said to be absorbed. Certain plant pigments such as chlorophyII can absorb light at specific wavelengths
Absorption spectroscopy A technique used to determine the ability of solutes to absorb light through a range of specified wavelength
AAcompldent A programme that enables identification of proteins by their amino acid composition
AACompsins A programme that compares the amino acid composition of a protein with other proteins in SWISS-MODEL
Ab see antibody
ab initio Describes an analysis method that is carried out from first principle. It is applied to gene prediction aigorithms, which do not incorporate homology searching and structural modeling algorithms that are not based on the structure of known proteins
AB variant of GM2 gangliosidosis A lipid storage disease due to a deficiency of a protein factor required for the activity of the enzyme hexosaminidase
ABC transporter proteins A large superfamily of membrane transport proteins that transfer peptides and other small moelcules using the energy derived from hydrolysis of ATP
Absorption spectrum The pattern of energy absorbed when light of varying length passes through a substance. The light absorbed is plotted against the wavelength. The absorption spectrum is unique for each substance and helps in identification of the substance
Abstract syntax notation A language used to describe structured data types formally. It is used by the NCBI to encode sequences, maps, taxonomic information, molecular structures and biological information so that it can easily accessed and exchanged by computer software
Abundant mRNAs A small number of individual mRNAs, each of the which is present in a large number of copies per cell
Abzymes Catalytic antibodies that cleave proteins or carbohydrates at specific residues. These are used as therapeutic agents, catalysts and for attacking specific viral or bacterial surface structures
Ac-Ds family A maize transposon family containing activator (Ac) elements that encode a functional transposase and dissociator (Ds) elements, which are defective derivatives of the Ac elements
Acanthocytosis The presence in the blood of erythrocytes with a thorny appearance due to protoplasmic projections
|
|
