Science Key Terms 1 Flashcards
(107 cards)
Acid
A substance with a pH less than 7
Activation Energy
The minimum energy required to initiate a chemical reaction
Active Immunity
Protection against a specific pathogen resulting from the production of antibodies in response to the presence of specific antigens.
Active Transport
Movement across a cell membrane that travels against the concentration gradient and thus requires energy. From areas of low to high concentrations.
Adaptive Defense
A specific response by the immune system to a given pathogen.
Adaptive Immune System
A kind of passive or active immunity in which antibodies to a particular antigen are present in the body.
Adhesiveness
A measure of how well dissimilar particles or surfaces cling to one another.
Adrenal
A gland above the kidney that produces hormones to regulate heart rate, blood pressure, and other functions.
Aldosterone
A hormone secreted by the adrenal gland that increases the reabsorption of sodium ions.
Allele
A specific copy of a gene
Allergies
An immune response to a foreign agent that is not a pathogen.
Alveoli
Tiny air sacs in the lungs where exchange of oxygen and carbon dioxide take place.
Amino Acids
The monomers that make proteins
Anaphase
The stage of mitosis in which the chromosomes move to opposite ends of the cell.
Anaphase I
The stage of meiosis I in which homologous chromosomes move to opposite ends of the cell.
Anaphase II
The stage of Meiosis II in which sister chromatids separate and move to opposite ends of the cell.
Anatomical Position
Standard positioning of the body as standing,, feet together, arms to the side, with head, eyes, and palms of hands forward.
Angiotensin II
A secretion that acts to restore blood volume and blood pressure by constricting blood vessels, stimulating thirst, and stimulating production of aldosterone and antidiuretic hormone.
anion
A negatively charged ion
Antagonist
The relaxed muscle in the pair of muscles that is involved in a given movement.
Antibody-mediated immunity
A defense that employs B cells to create antibodies that tag pathogens for later destruction. Also known as humoral immunity.
antibody
A blood protein that counteracts a specific antigen
antidiuretic hormone
A secretion from the pituitary gland that increases the amount of water able to be reabsorbed from a collecting duct.
antigen-presenting cell
A cell that displays foreign antigens with major histocampitability complexes on their surfaces.