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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Acromegaly Acute Glomerulonephritis
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Acidosis A pathological condition in which the blood pH is decreased. This may be metabolic or respiratory
Acquired A trait that is developed in response to the environment, and not inherited
Acridine dyes Positively charged polycyclic molecules that intercalate into DNA, inducing Frameshift mutations
Acridine orange a group of chemical mutagens that includes proflavine and acriflavine which intercalate into DNA between tow adjacent base pairs.
These compounds cause Frameshift mutations because they are capable of causing deletion or insertion of a base pair during replication
Acrocentric A monocentric chromosome with its centromere in the terminal region
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Acromegaly Growth hormone excess in adults. It occurs after epiphyseal fusion and presents frequently in middle age. The disease is mostly due to a primary pituitary aetiology and GHRI induced acromegaly is rare. The following clinical features are seen: overgrowth of bone and soft tissue, excessive sebaceous gland secretion and oily skin, increased basal metabolic rate (BMR), increased sweating, neurological and musculosekeletal symptoms, and hirsutism and amenorrhoea in women, impaired glucose tolerance an diabetes mellitus develop in some patients. Approximately 40 per cent of pateients with acromegaly have a G-protein linked disease with one or two mutations abolishing its w GTPase activity. Life expectancy is short and death can occur due to cardiovascular, cerebrovascular, and respiratory disease as well as malignancy
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Acrosomal vesicle A region at the head of a sperm cell that contains a sac of hydrolytic enzymes capable of digesting the protective coating of the egg
Acrosome An apical organelle found in the head of a spermatozoon
Acrosome reaction A reaction that takes place when a sperm begins to enter the egg. This involves release of hydrolytic enzymes form the acrosomal vesicle, Which enable the sperm to penetrate the zona pellucida
Acrylamide A substance capable of polymerization that is used as a support medium in gel electrophories. This is used in the separation of nucleic acid or protein mixtures based on their size or molecular weight
Acrylamide gels See polyacrylamide gels
ACTH See adrenocorticotrophic hormone
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Actin-binding protein A protein that associates with actin monomers or actin filaments and alters their properties. Examples include myosin and profiling
Actinomyces a genus of Gram-positive filamentous anaerobic bacteria found in the mouth and throat. Non-acid-fast, nonmotile, soil inhabiting plant and animal parasites
Actinomycin D An antibiotic produced by Streptomyces parvullus that inhibits transcription in both prokaryotes and eukaryotes. It blocks the action of RNA pol I which catalyses the synthesis of rRNA and forms complexes with DNA by intercalating between G-C pairs. It is used as a chemotherapeutic agent in conjunction with other drugs
Action potential Self-propagating electrical excitation in the plasma membrance of a nerve or muscle cell. Action potential is rapid and transient. It is responsible for signaling in the nervous system
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Activated carrier A small diffusible molecule (eg. ATP, NADPH) that stores energy in the form of energy-rich covalent bonds that are readily exchangeable
Activated charcoal; activated carbon Charcoal that has been treated to remove hydrocarbons and to increase its adsorptive properties. If functions by condensing and holding a solute or gas on its surface. It is capable of removing inhibitory substances in nutrient medium. Activated charcoal may differ in origin and in composition. See charcoal
Activated complex The highest free energy state of a complex during the formation of products from reactants
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Actin A major constituent of the cytoskeleton of eukaryotic cells. It is also a component of the contractile apparatus of the skeletal muscle. The monomeric form is called globular or G-actin, while the polymer is called filamentous or F-actin
Activated sludge process Aerobic treatment process that uses aerobic microorganism present in sewage sludge to break down organic matter in sewage
Activation energy (∆G) The amount of energy in Joules required to convert all the molecules in 1 mole of a reactant from the ground state to the transition state
Acrodermatitis enteropathica A rate, autosomal recessive e inherited disease, associated with severe zinc deficiency as a result of defective intestinal absorption. This occurs in infants after weaning from breast milk. Breast milk contains picolinc acid, which is postulated to be a facilitator of zinc absorption. The condition is characterized by rough and thick skin, baldness, diarrhoea, poor growth and development, infections and sometimes death
ctivation function 1(AF-1) A region in the amino terminal half of the glucocorticoid receptor that modules promoter function
Activator 1. protein which binds to DNA increasing transcription of some genes. 2 A compound that binds to an allosteric site on an enzyme, enabling the substrate to bind to the active site of the enzyme (positive modulator of an allosteric enzyme) 3. Coarse inert material, such as gravel, that is mixed with soil to increase its porosity
Activator (Ac) elements Autonomous transposable elements found in maize that encode a functional transposase
Active immunity Immunity acquired through exposure to antigen and response of one’s own immune system
Active site 1. A site on the surface of a catalyst at which activity occurs. 2. The site on the surface of an enzyme molecule that binds the substrate molecule and catalyses its conversion to products
Active transport Energy-requiring transport of a substance across the membrane against a concentration gradient. This type of transport requires energy. A classic example of active transport is the transport of Na+ out of the cell I exchange for K+ by the action of Na+-K+-ATPase
Activity The true thermodynamic activity or potential of a substance. This is distinct from the molar concentration of the substance
Activity-based proteomics Identification and analysis of changes in active proteins in different cell types and under different conditions. This is a direct method for analysing the biochemical mechanisms or disease comparsed to standard genomics and proteomics techniques
Activity coefficient The factor by which the numerical value of the concentration of a solute is multiplied in order to calculate its true thermodynamic acitivity
Acute A short and relatively severe course (of a disease)
Acute glomerulonephritis Glomerulonephritis of sudden onset that usually follows a haemolytic streptococcal infection of the throat or other bacterial, viral or parasitic infections. The glomerular function is impaired but the renal plasma flow in normal. The filtration fraction is low and tubular function is only slightly impaired. Acute glomerulonephritis is characterized by oliguria, haematuria, proteinuria, azotaemia, hypertension and oedema. A few patients develop anuria leading to acute renal failure, while some patients progress to chronic glomerulonephritis and terminal renal failure
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