Kapitel 20 Flashcards
Cell junction that helps hold together epithelial cells in a sheet of epithelium; actin filaments inside the cell attach to its cytoplasmic face.
adherens junction
Describes the top or the tip of a cell - structure - or organ; in an epithelial cell - for example - this surface is opposite the base - or basal surface.
apical
Situated near the base; opposite of apical.
basal
Thin mat of extracellular matrix - secreted by epithelial cells - upon which the cells sit.
basal lamina
A member of a family of Ca2+-dependent proteins that mediates the attachment of one cell to another in animal tissues.
cadherin
Disease caused by abnormal and uncontrolled cell proliferation - followed by invasion and colonization of body sites normally reserved for other cells.
cancer
Specialized region of connection between two cells or between a cell and the extracellular matrix.
cell junction
Mechanically strong fibrous layer deposited by a cell outside its plasma membrane. Prominent in most plants - bacteria - algae - and fungi - but not present in most animal cells.
cell wall
Long - thin strand of cellulose that helps strengthen plant cell walls.
cellulose microfibril
Triple-stranded - fibrous protein that is a major component of the extracellular matrix and connective tissues; it is the main protein in animal tissues - and different forms can be found in skin - tendon - bone - cartilage - and blood vessels.
collagen
Tissues such as bone - tendons - and the dermis of the skin - in which extracellular matrix makes up the bulk of the tissue and carries the mechanical load.
connective tissue
Specialized cell–cell junction - usually formed between two epithelial cells - that serves to connect the ropelike keratin filaments of the adjoining cells - providing tensile strength.
desmosome
An undifferentiated cell type derived from the inner cell mass of an early mammalian embryo and capable of differentiating to give rise to any of the specialized cell types in the adult body.
embryonic stem cell (ES cell)
Sheet of cells covering an external surface or lining an internal body cavity.
epithelium (plural epithelia)
Complex network of polysaccharides (such as glycosaminoglycans or cellulose) and proteins (such as collagen) secreted by cells. A structural component of tissues that also influences their development and physiology.
extracellular matrix
Cell type that produces the collagen-rich extracellular matrix in connective tissues such as skin and tendon. Proliferates readily in wounded tissue and in tissue culture.
fibroblast
Extracellular matrix protein that helps cells attach to the matrix by acting as a “linker” that binds to a cell-surface integrin molecule on one end and to a matrix component - such as collagen - on the other.
fibronectin
In animal tissues - specialized connection between juxtaposed cells through which ions and small molecules can pass from one cell to the other.
gap junction
An increased rate of mutation often caused by defects in the systems that govern the accurate replication and maintenance of the genome; the resulting mutations sometimes drive the evolution of cancer.
genetic instability
Polysaccharide chain that can form a gel that acts as a “space filler” in the extracellular matrix of connective tissues; helps animal tissues resist compression.
glycosaminoglycan (GAG)
Structure that anchors epithelial cells to the basal lamina beneath them.
hemidesmosome
Family of transmembrane proteins present on cell surfaces that enable cells to make and break attachments to the extracellular matrix - allowing them to crawl through a tissue.
integrin
The spread of cancer cells from the initial site of the tumor to form secondary tumors at other sites in the body.
metastasis
A gene that - when activated - can potentially make a cell cancerous. Typically a mutant form of a normal gene (proto-oncogene) involved in the control of cell growth or division.
oncogene
Cell–cell junction that connects one plant cell to the next; consists of a channel of cytoplasm lined by membrane.
plasmodesma (plural plasmodesmata)
Capable of giving rise to any type of cell or tissue.
pluripotent
Molecule consisting of one or more glycosaminoglycan chains attached to a core protein; these aggregates can form gels that regulate the passage of molecules through the extracellular medium and guide cell migration.
proteoglycan
Gene that when mutated or overexpressed can transform a normal cell into a cancerous one.
proto-oncogene
The artificial production of genetically identical copies of an animal by - for example - the transplantation of a somatic cell nucleus into an enucleated fertilized egg.
reproductive cloning
Relatively undifferentiated - self-renewing cell that produces daughter cells that can either differentiate into more specialized cell types or can retain the developmental potential of the parent cell.
stem cell
Procedure that uses nuclear transplantation to generate cells for tissue repair and other such purposes - as opposed to producing whole multicellular individuals.
therapeutic cloning
Cell–cell junction that seals adjacent epithelial cells together - preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other.
tight junction
Cooperative assembly of cells and matrix woven together to form a distinctive multicellular fabric with a specific function.
tissue
A gene that in a normal tissue cell inhibits cancerous behavior. Loss or inactivation of both copies of such a gene from a diploid cell can cause it to behave as a cancer cell.
tumor suppressor gene
Member of a family of extracellular signal molecules that regulates cell proliferation and migration during embryonic development and that maintains stem cells in a proliferative state.
Wnt protein
Population of cells derived from a plant or animal capable of dividing indefinitely in culture.
cell line
Structural polysaccharide consisting of long chains of covalently linked glucose units. Provides tensile strength in plant cell walls.
cellulose
