BIO - TERMS - FREQUENCY > 1 PT 9 Flashcards
accommodation
The focusing of light by changing the shape of the eye’s lens. // (ā-kom′ŏ-dā′shŭn) Changing the lens shape in order to focus on a nearby object.
adenosine deaminase (ADA) deficiency
A cause of severe combined immunodeficiency. // An inherited defect characterized by nonproduction of the enzyme adenosine deaminase, which leads to the accumulation of toxic purine nucleosides and nucleotides in cells, resulting in the death of most developing lymphocytes within the thymus. It is a cause of severe combined immunodeficiency. adhesins Cell-surface proteins on bacteria that enable them to bind to the surfaces of host cells.
AIRE (autoimmune regulator)
A protein expressed by a subpopulation of epithelial cells in the thymus that stimulates the production of small amounts of self proteins characteristic of other organs, exposing developing thymocytes to these proteins for the purpose of self-tolerance. // Gene encoding a protein (autoimmune regulator) that is involved in the expression of numerous genes by thymic medullary epithelial cells, enabling developing T cells to be exposed to self proteins characteristic of other tissues, thereby promoting tolerance to these proteins. Deficiency of AIRE leads to an autoimmune disease, APECED.
alpha (α) decay
The form of radioactive decay that occurs when an unstable nucleus emits a particle composed of two protons and two neutrons.
amplitude
The vertical height of a crest (or depth of a trough) of a wave; a measure of wave intensity. // The height of a wave measured from the midpoint to the maximum. The intensity of radiant energy is proportional to the square of the wave’s amplitude.
anterior
Toward the front of the body. // An anatomical reference meaning toward the nose or rostral.
apical
(ap′i-kăl) Related to the tip or extremity of a conical or pyramidal structure; opposite of basal. // Referring to the tip of a cell, a structure, or an organ. The apical surface of an epithelial cell is the exposed free surface, opposite to the basal surface. The basal surface rests on the basal lamina that separates the epithelium from other tissue.
astrocyte
(as′trō-sı̄t) Largest and most abundant glial cell of the central nervous system. // A glial cell in the brain that supports neurons and regulates the extracellular ionic and chemical environment.
autograft
A tissue graft from one’s self. // A graft of tissue from one site to another on the same individual. autoimmune disease Disease in which the pathology is caused by adaptive immune responses to self antigens.
B-cell antigen receptor, B-cell receptor (BCR)
The transmembrane immunoglobulin protein on the surface of a B cell that serves as its receptor for antigen. // The cell-surface receptor on B cells for specific antigen. It is composed of a transmembrane immunoglobulin molecule (which recognizes antigen) associated with the invariant Igα and Igβ chains (which have a signaling function). On activation by antigen, B cells differentiate into plasma cells producing antibody molecules of the same antigen specificity as this receptor.
beta-catenin (β-catenin)
Multifunctional cytoplasmic protein involved in cadherin-mediated cell–cell adhesion, linking cadherins to the actin cytoskeleton. Can also act independently as a transcription regulatory protein. Has an important role in animal development as part of a Wnt signaling pathway.
blood pressure
The pressure of blood against the vessel walls. // Measure of the force of blood pushing against the blood vessel wall; commonly measured in the brachial artery.
calnexin
Carbohydrate-binding chaperone protein in the endoplasmic reticulum (ER) membrane that binds to oligosaccharides on incompletely folded proteins and retains them in the ER. // A chaperone protein in the endoplasmic reticulum (ER) that binds to partly folded members of the immunoglobulin superfamily of proteins and retains them in the ER until folding is complete.
Carboxylic acids, RCO2H
Compounds containing the -CO2H functional group. // An organic acid containing the functional group — COOH.
cell-adhesion molecule (CAM)
A molecule on the cell surface that causes cells to adhere to one another. // Cell-surface proteins of several different types that mediate the binding of one cell to other cells or to extracellular matrix proteins. Integrins, selectins, and members of the immunoglobulin gene superfamily (such as ICAM-1) are among the cell-adhesion molecules important in the operation of the immune system.
chemiosmotic coupling (chemiosmosis)
Coupling of ATP synthesis to electron transfer via a transmembrane difference in charge and pH. // Mechanism in which an electrochemical proton gradient across a membrane (composed of a pH gradient plus a membrane potential) is used to drive an energy-requiring process, such as ATP production or the rotation of bacterial flagella.
cholecystokinin (CCK)
Hormone released from the duodenum in response to lipid-rich chyme; stimulates secretion from the pancreas and gallbladder. // A peptide found within some neurons of the central and peripheral nervous systems and in some endothelial cells lining the upper gastrointestinal tract; a satiety signal that inhibits feeding behavior, in part, by acting on axons of the vagus nerve that respond to gastric distension.
Classical pathway
One of three complement pathways that lead to activation of C3-C5 convertases; activation occurs by direct interaction of C1q or C3b proteins with a viral protein/antibody complex on the surface of an infected cell or a virus particle. (Chapter 3) // The complement-activation pathway that is initiated by C1 binding either directly to bacterial surfaces or to antibody bound to the bacteria, thus flagging the bacteria as foreign. See also alternative pathway, lectin pathway.
Colony
A compact collection of cells produced by the division of a single progenitor cell. // A visible mass of microbial cells arising from one cell or from a group of the same microbes.
conjugate acid
Any base to which a proton has been added. // The product that results from protonation of a Brønsted–Lowry base.
Contig
A set of overlapping clones that provide a physical map of a portion of a chromosome. // A series of overlapping clones or a continuous sequence defining an uninterrupted section of a chromosome.
cross-presentation
A process in which extracellular proteins taken up by specialized dendritic cells can give rise to peptides that can be presented by class I MHC proteins to cytotoxic T cells. // The process by which extracellular proteins taken up by dendritic cells can give rise to peptides presented by MHC class I molecules. It enables antigens from extracellular sources to be presented by MHC class I molecules and activate CD8 T cells.
decarboxylation
The removal of CO2 from an amino acid. // The loss of carbon dioxide from a molecule. β-Keto acids decarboxylate readily on heating.
dextrorotatory
Capable of rotating the plane of polarization of light clockwise. // A word used to describe an optically active substance that rotates the plane of polarization of plane-polarized light in a right-handed (clockwise) direction.
dipole moment (μ)
A measure of the separation of positive and negative charge in a molecule. // A measure of the net polarity of a molecule. A dipole moment arises when the centers of mass of positive and negative charges within a molecule do not coincide.
DNA library
A collection of cloned DNA fragments. // Collection of cloned DNA molecules, representing either an entire genome (genomic library) or complementary DNA copies of the mRNA produced by a cell (cDNA library).
duodenum
(dū-ō-dē′nŭm, dū-od′ĕ-nŭm) First section of small intestine. // First of three segments in the small intestine. Major site of absorption of nutrients.
elastic fiber
Extensible fiber formed by the protein elastin in many animal connective tissues, such as in skin, blood vessels, and lungs, which gives them their stretchability and resilience. // Protein that allows tissues to stretch and return to their original shape; located within connective tissues.
electroporation
A technique by which DNA is inserted into a cell using an electrical current. // A process whereby cell membranes are made permeable to DNA by applying an intense electric current.
endothelial cell
Cell type that forms the endothelium, the epithelium of a blood vessel wall. // Flattened cell type that forms a sheet (the endothelium) lining all blood and lymphatic vessels.
ergot
A toxin produced in sclerotia by the fungus Claviceps purpurea that causes ergotism. // A fungus (Claviceps purpurea) that infects grasses (especially rye) and produces pharmacologically active alkaloids.
extension
(eks-ten′shŭn) Movement of a joint in an anteriorposterior plane that increases the articulating angle. // The direction of movement that opens a joint. extensor A muscle that causes extension when it contracts.
Fc receptor
Family of cell-surface receptors that bind the Fc portions of different immunoglobulins: Fcγ receptors bind IgG, for example, and Fcε receptors bind IgE. // One of a family of cell-surface receptors that bind the tail region (Fc region) of an antibody molecule. Different Fc receptors are specific for different classes of antibodies, such as IgG, IgA, or IgE.
Flavonoid
Reported to reduce capillary fragility, and inhibit in vitro aldolase reductase (has a role in diabetic cataracts) and o-methyltransferase (inactivates epinephrine and norepinephrine) // A class of plant secondary metabolites that are composed of two aromatic rings connected by a three carbon bridge; according to the degree of oxidation of the three carbon bridge, flavonoids are classified into different subgroups including anthocyanidins and flavonols.
fornix
(fōr′niks; pl., fornices, -nisēz) Arch-shaped structure. // A bundle of axons that originates in the hippocampal formation, loops around the thalamus, and terminates in the diencephalon.
gamma (γ) ray emission
The form of radioactive decay that occurs when an unstable nucleus emits extremely high frequency electromagnetic radiation.
genetic engineering
The manipulation of an organism’s genome by inserting or deleting DNA. // Any process by which genetic material, particularly DNA, is altered by a molecular biologist.
Glycemic index
A measure for the extent to which a food raises the blood glucose level. // The glycemic response of a food relative to a standard carbohydrate-containing food.
gonad
(gō′nad) Organ that produces sex cells and sex hormones; the ovaries in a female and the testes in a male. // A sexual organ (that is, ovary or testis) that produces gametes.
ground state
The lowest energy state in an atom, ion, or molecule. // The normal, stable form of an atom or molecule; as distinct from the excited state.
