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Abscisic Acid
Plant hormone that inhibits growth and influences stomatal closure.
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Abscission
Separation of a leaf or fruit from a plant.
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Acceptor Molecules
Compounds such as NAD and FAD that can accept hydrogen atoms and electrons removed from compounds and transfer them to other compounds.
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Acquired Immune Deficieny Syndrome (AIDS)
Disease caused by the human immunodeficiency virus (HIV) that results in significant damage to the immune system, making the infected person particularly susceptible to infectious disease.
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Acquired Immunity
Characterised by the presence in an individual of antibodies to a particular infective agent: in active acquired immunity, individuals produce their own antibodies as a result of exposure to an antigen; in passive acquired immunity, individuals recieve antibodies from an outside source.
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Active Immunity
Immunity that develops when an organism makes its own antibodies; antibodies may be produced naturally in response to chance infection or maybe induced by vaccination.
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Active Transport
Net movement of dissolved substances across a cell membrane by an energy-requiring process that moves substances against a concentration gradient from a region of lower to higher concentration.
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Adenine
One of the Purine bases found in the nucleotides that are the building blocks of DNA and RNA.
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Adenosine Diphosphate
Compoud cotaining adenine ad two molecules of phosphate; in an energy - requiring reaction, it can combine with a third molecule of phosphate to form ATP.
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Adenosine Triphosphate
Copound containing Adenosine and three phosphate molecules, the major supplies of which are produced in the mitochondria; common source of chemical energy for cells.
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Aerobic Respiration
Break down of glucose to simple inorganic compounds in the presence of oxygen and with release of energy that is transferred to ATP.C6H12O6 + 6O2 >6CO2+6H2O glucose +oxygen> carbon dioxide +water
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Affector Neurons
Also called sensory neurons; type of nerve cell that transmits information about changes in external or internal conditions to the central nervous system.
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Agglutination
Clumping of cells or particles brought about by antibodies binding to antigens on the surfaces of the cells or particles.
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Albinism
Inherited condition in which pigment production does not occur normally; in the form known as oculo-cutaneous albinism, pigment is absent from the skin, hair and iris.
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Allergic Reaction
(Allergy) rapid immune responses to normally harmless antigens such as dust or pollen; involves action of the mast cells.
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Alpha cells
Cells in the pancreas that synthesise and secrete the hormone gycagon.
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Amino Acid Derivatives
One category of water soluble hormone.
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Amino Acids
Basic building blocks or sub units of polypeptide chains and proteins.
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Amniocentesis
Procedure in which a sample is obtained of the amniotic fluid that surrounds a fetus in the uterus and contains fetal cells.
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Amiotic fluid
Fluid surrounding and protecting the embryo or fetus in the amniotic sac
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Anaerobic
Refers to an organism that does not require oxygen to live; refers to an environment in which oxygen is not present.
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Anaerobic Respiration
Form of respiration occuring in the absence of oxygen in which glucose is broken down to smaller compounds, such as lactate, with release of energy that is transferred to ATP.
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Antibiotics
Naturally occuring substances that inhibit the growth of, or destroy, bacteria and other micro-organisms
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Antibodies
Proteins produced by animals in response to antigens and which react specifically with the antigen that induced their formation.
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Anti-Codon
Sequence of three bases in a transfer RNA molecule that can pair with the complementary codon messenger RNA molecule.
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Antigens
Compounds, usually proteins,that can trigger the immune system to respond in various ways, including antibody production.
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Antitoxins
Protein produced by animals in response to toxin which reacts specifically with the toxin that iduced its formation.
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Apical Dominance
Influence exerted by a terminal bud that suppresses growth of lateral buds.
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Apoptosis
The natural death of cells, also called programmed cell death.
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Auto-Immune Disease
Diseases in which the immune system fails to identify 'self' material and makes antibodies against the body's own tissues.
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Autonomic Nervous System
Also called involuntary nervous system; in vertebrates, nerves that transmit messages away from the brain and spinal cord to smooth (involuntary)muscle, heart and various glands.
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Auxin
Group of plant hormones that control cell elongation found in tip of plant (coleoptile) grows towards the sun is produced more on the side away from sun
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Axon
Extention of nerve cell along which impulses are transmitted away from that cell.
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B Cells
Lymphocytes that give rise to plasma cells that produce antibodies against foriegn material.
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Bacteria
Microscopic, usually uncellular, organism, and member of Kingdom Monera
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Bacteriophages
Types of virus that infect bacteria.
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Base
Varying part of the structure of nucleotides, the building blocks of DNA and RNA; bases in DNA are Adenine, Cytosine, Guanine and Thymine; bases in RNA are A,G,C and uracil U.
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B-Memory Cells
Particular kind of B cells that can respond quickly to a specific antigen that has been previously encountered
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Bone Marrow
Fatty substances in the internal cavity of bones, the site of blood cells formation. and blood cells and B and T cells.
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C3 Plants
Plants in which the first product of the light independent stage of photosynthesis is a compoud containing three carbon atoms.
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C4 plants
Plants in which the first product of the light independent stage of photosynthesis is a compoud containing four carbon atoms.
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Calvin Cycle
Cycle of reactions occuring in the stroma of chloroplasts in the light independent stage of photosythesis during which carbon dioxide is progressively reduced to sugar.
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Capsule
Gelatinous layer surrounding the cell wall of some bacteria.
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Carbohydrates
Organic compounds that include sugars, starch and cellulose and are made of carbon, hydrogen and oxygen.
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Carbon Dioxide Fixation
Also called carbon fixation; occurs during photosynthesis when carbon is moved from a gas, carbon dioxide, into an organic compound.
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Carrier
In infection, refers to a person who shows no sign of an infectious disease but is host to the causative agent and can transmit it to other people in genetics, refers to a heterozygous organism that does not show a particular trait but can transmit to its offspring to the allele responsible for that trait.
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Carrier Protein
Protein tht binds to specific substance and failitates its movement; may be carrier for lipophillic hormone for transport in the blood; also refers to proteins that facilitate movement across the plasma membrane.
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Cell Body
That part of a neuron that contains the nucleus
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Cell Wall
Semi-rigid structure located outside the cell membrane of plants,algae, fungi and bacteria.
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Cellular Agents
In the context of disease and infection refers to cellular organisms such as bacteria, in contrast to infective agents such as viruses and prions that lack a cellualr structure.
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Cellular Immunity
Response to infection involving action phagocytes and T cells.
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Cellular respiration
Process of transferring energy present in organic compounds t a form useable by cells typically ATP.
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Chargaff's Rule
Regularity observed by Chargaff that, in DNA, the relative proportions of A and T are equal and, similarl, the proportion of C is equalto that of G.
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Chemical Energy
Potential Energy stored in substances that become available when certain types of chemical reactions occur.
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