Category: A

  • Aneuploidy

    An abnormal number of chromosomes, usually associated with miscarriage, or developmental abnormalities such as Down’s syndrome where there are three copies of chromosome 21 instead of two. Condition in which the number of chromosomes is either more or fewer than normal. The state in which there is an abnormal number of chromosomes: for example, down’s…

  • Anaerobic threshold

    The level of exercise at which the rate of oxygen uptake into muscle becomes limiting and there is anaerobic metabolism to yield lactate. The point at which the body can no longer meet its demand for oxygen and anaerobic metabolism is accelerated. The point at which anaerobic energy begins to supplement the already sizable aerobic…

  • Anaemia, pernicious

    Anaemia due to deficiency of vitamin B12, most commonly as a result of failure to absorb the vitamin from the diet. There is release into the circulation of immature precursors of red blood cells (megaloblastic anaemia) and progressive damage to the spinal cord (subacute combined degeneration), which is not reversed on restoring the vitamin.  

  • Anabolism

    The process of building up or synthesising. The phase of intermediary metabolism concerned with the energy-requiring biosynthesis of cell components from smaller precursor molecules. A phase of metabolism characterized by a chemical synthesis within the body. The process of building up complex chemical substances on the basis of simpler ones. The totality of reactions that…

  • Anabolic hormones

    Natural or synthetic hormones that stimulate growth and the development of muscle tissue.  

  • Amylose

    The straight chain form of starch, with only al-4 bonds. About 20-25% of most starches; the remainder is amylopectin. A straight chain polysaccharide found in starch. The form of starch that consists of unbranched polymers, containing approximately 4,000 glucose units per molecule (polysaccharide). It is present in potatoes at 23-29% content (variation is thought to…

  • Amylopectin

    The branched chain form of starch, with branches formed by al-6 bonds. About 75-80% of most starches; the remainder is amylose. A branched polysaccharide found in starch. The form of starch that consists of multi-branched polymers, containing approximately 100,000 glucose units per molecule (polysaccharide). A branched chain polymer of glucose found in plants. The insoluble…

  • Amylodyspepsia

    An inability to digest starch.  

  • Amylases

    Enzymes that hydrolyse starch. a-Amylase (dextrinogenic amylase or diastase) acts to produce small dextrin fragments from starch, while (3-amylase (maltogenic amylase) liberates maltose, some free glucose, and isomaltose from the branch points in amylopectin. Salivary and pancreatic amylases are a-amylases. An enzyme that hydrolizes starch and glycogen to maltose; Ptyalin. An enzyme that catalyses the…

  • Aminotransferase

    Any enzyme that catalyses the reaction of transamination. Enzymes that catalyze the transfer of an amino group (-NH2 or -NH3) from one carbon chain to another.