Chap 20 (Cell Communities, Tissues, Stem Cells & Cancer) Terms

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Adherens Junction

Back 1

Cell junction that helps hold together epithelial cells in a sheet of epithelium; actin filaments inside cell attach to its cytoplasmic face

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Apical

Back 2

Describes the top or tip of the cell, structure or organ; in an epithelial cell, for example, this surface is opposite the base, or basal surface.

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Basal

Back 3

Situated near the base, opposite of apical

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Basal Lamina

Back 4

Thin mat of extracellular matrix, secreted by epithelial cells, upon which the cells sit

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Cadherin

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A member of a family of Ca+2-dependent proteins that mediates the attachment of one cell to another in animal tissue (also pg 402 in Biochem)

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Cancer

Back 6

Disease caused by abnormal and uncontrolled cell proliferation, followed by invasion and colonization of body sites normally reserved for other cells

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Cell Junction

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Specialized region of connection between two cells or between a cell and the extracellular matrix

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Cell Wall

Back 8

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.

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Cellulose Microfibril

Back 9

Long, thin strand of cellulose that helps strengthen plant cell walls.

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Collagen

Back 10

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

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Connective Tissue

Back 11

Tissue 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.

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Desmosome

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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

Hint 12

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Embryonic Stem Cell (ES cell)

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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

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Epithelium (plural: Epithelia)

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Sheet of cells covering an external surface or lining an internal body cavity

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Extracellular Matrix

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Complex network of polysaccharides (such as glycosaminoglycans or cellulose) and proteins (such as collagen) secreted by cells. A structural component of tissue that also influences their development and physiology.

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Fibroblast

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Cell type that produces the collagen-rich extracellular matrix in connective tissue such as skin and tendon. Proliferates readily in wounded tissue and in tissue culture

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Fibronectin

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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 the matrix component , such as collagen, on the other

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Gap Junction

Back 18

In animal tissue, specialized connections between juxtaposed cells through which ions and small molecules can pass from one cell to the other

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Genetic Instability

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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

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Glycosaminoglycan (GAG)

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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

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Hemidesmosome

Back 21

Structure that anchors epithelial cells to the basal lamina beneath them

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Induced pluripotent stem (iPS) cell

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Somatic cell that has been reprogrammed to resemble and behave like a pluripotent embryonic stem (ES) cell through the artificial introduction of a set of genes encoding particular transcription regulators.

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Integrin

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Family of transmembrane proteins present on cell surfaces that enable them to make and break attachments to the extracellular matrix, allowing them to crawl through a tissue.

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Metastasis

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The spread of cancer cells from the initial site of the tumor to form secondary tumors at the other sites in the body

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Oncogene

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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

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Plasmodesma (Plural; Plasmodesmata)

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Cell-cell junction that connects one plant cell to the next; consists of a channel of cytoplasm lined by membrane

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Pluripotent

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Capable of giving rise to any cell or tissue

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Proteoglycan

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Molecule consisting of one or more gylcosaminoglycan 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

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Proto-oncogene

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Gene that when mutated or overexpressed can transform a normal cell into a cancerous one

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Reproductive cloning

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The artificial production of genetically identical copies of an animal by, for example, the transplantation of a somatic cell nucleus into an enucleated fertilized

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Stem cell

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Relatively undifferentiated, self-renewing cell that produces daughter cells that can either differentiate into more specialized cell types or can retain the development potential of the parent cell

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Therapeutic Cloning

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Procedure that uses nuclear transplantation to generate cells for tissue repair and other such purposes, as opposed to producing whole multicellular individuals.

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Tight junction

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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

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Tissue

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Cooperatively assembly of cells and matrix woven together to form a distinctive multicellular fabric with a specific function

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Tumor Suppressor Gene

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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

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Wnt protein

Back 36

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