Biological Terms Flashcards
What does the term activation energy mean?
The energy required to bring about a reaction. The activation energy is lowered by the presence of enzymes.
What does the term active immunity mean?
The resistance to disease resulting from the activities of an individual’s own immune system whereby an antigen induces plasma cells to produce antibodies.
What does the term active site mean?
A group of amino acids that makes up the region of an enzyme into which the substrate fits in order to catalyse a reaction.
What does the term active transport mean?
It is the movement of a substance from a region where it is in a low concentration to a region where it is in a high concentration. The process requires the expenditure of metabolic energy.
What does the term adenosine triphosphate (ATP) mean?
It is an activated nucleotide found in all living cells that acts as an energy carrier. The hydrolysis of ATP leads to the formation of adenosine diphosphate (ADP) and inorganic phosphate, with the release of energy for the body.
What does the term allele mean?
It is one of a number of alternative forms of a gene. For example, the gene for the shape of a pea seeds has two alleles: one for ‘round’ and one for ‘wrinkled’.
What does the term allele frequency mean?
It is the number of times an allele occurs within the gene pool.
What does the term allergen mean?
It is a normally harmless substance that causes the immune system to produce an immune response.
What does the term allergy mean?
It is the response of the immune system to an allergen. Examples include hay fever and asthma.
What does the term antibiotic mean?
It is a substance produced by living organisms that can destroy or inhibit the growth of microorganisms.
What does the term antibiotic resistance mean?
It is the development in microorganisms of mechanisms that prevent antibiotics from killing them.
What is an antibody?
It is a protein produced by lymphocytes in response to the presence of the appropriate antigen.
What is an anticodon?
It is a sequence of three adjacent nucleotides on a molecule of transfer RNA (tRNA) that is complimentary to a particular codon on a messenger RNA molecule. These join up in translation and the amino acids on tRNA molecule join together with peptide bonds then they are released as a peptide chain at the end.
What is an antigen?
A molecule that triggers an immune response by lymphocytes.
