Terms A Flashcards
Activation energy
Energy required to bring about a reaction. The activation energy is lowered by the presence of enzymes
Active immunity
Resistance to disease resulting from the activities of an individuals own immune system whereby an ANTIGEN induces plasma cells to produce ANTIBODIES
Active site
A group of amino acids that make up the region of an enzyme into which the substrate fits in order to catalyse a reaction
Active transport
Movement of a substance from a region of LOW concentration to a region of HIGH concentration. The process requires the expenditure of METABOLIC energy
Aerobic
Connected with the presence of free oxygen. AEROBIC RESPIRATION requires free oxygen to release energy from glucose.
ALLELE
One of a number of alternative forms of a GENE. Eg the gene for the shape of a pea seed has TWO ALLELES : one for ROUND and one for WRINKLED
Allergen
A normally harmless substance that causes the immune system to produce an immune response
Allergy
The response of the immune system to an ALLERGEN eg hay fever and ASTHMA
Antibiotic
A substance produced by living organisms that can destroy or inhibit the growth of microorganisms
Antibiotic resistance
The development in microorganisms that prevent ANTIBIOTICS from killing them
Antibody
A protein produced by LYMPHOCYTES in response to the presence of the appropriate antigen
Anticodon
A sequence of three adjacent NUCLEOTIDES on a molecule of transfer RNA that is complimentary to a particular CODON on a messenger RNA molecule
Antigen
A molecule that triggers an immune response by LYMPHOCYTES
Antioxidant
Chemical which reduces or prevents OXIDATION. Often used as an additive to prolong the shelf life of certain foods
Apoplastic pathway
Route through the cell wall and intercellular spaces of plants by which water and dissolved substances are transported.
See also symplastic pathway
