Ch 20 - Cell Communities; Tissues, Stem Cells and Cancer

Question 1

adherens junction

Answer 1

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

Question 2

apical

Answer 2

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

Question 3

basal

Answer 3

situated near the base; opposite of apical

Question 4

basal lamina

Answer 4

thin mat of extracellular matrix, secreted by epithelial cells upon which these cells sit

Question 5

cadherin

Answer 5

a member of a family of Ca2+-dependent proteins that mediates the attachment of one cell to another in animal tissues

Question 6

cancer

Answer 6

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

Question 7

cell junction

Answer 7

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

Question 8

cell wall

Answer 8

mechanically strong fibrous layer deposited outside the plasma membrane of some cells. prominent in most plants, bacteria, algae and fungi, but not present in most animal cells

Question 9

cellulose microfibril

Answer 9

long, thin polysaccharide fiber that helps strengthen plant cell walls

Question 10

collagen

Answer 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

Question 11

connective tissue

Answer 11

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

Question 12

desmosome

Answer 12

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.

Question 13

differentiated cell

Answer 13

cell that has undergone a coordinated change in gene expression, enabling it to perform a specialized function

Question 14

embryonic stem (ES) cell

Answer 14

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

Question 15

epithelium (plural epithelia)

Answer 15

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

Question 16

extracellular matrix

Answer 16

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

Question 17

fibroblast

Answer 17

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

Question 18

fibronectin

Answer 18

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

Question 19

gap junction

Answer 19

in animal tissues, specialized connection between juxtaposed cells through which ions and small molecules can pass from one cell to the other

Question 20

genetic instability

Answer 20

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

Question 21

glycosaminoglycan (GAG)

Answer 21

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

Question 22

hemidesmosome

Answer 22

structure that anchors epithelial cells to the basal lamina beneath them

Question 23

induced pluripotent stem (iPS) cell

Answer 23

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

Question 24

integrin

Answer 24

one of a 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

Question 25

metastasis

Answer 25

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

Question 26

oncogene

Answer 26

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 and division.

Question 27

organoid

Answer 27

a miniature, three-dimensional collection of tissues formed from the proliferation, differentiation and self-assembly of pluripotent cells in culture

Question 28

plasmodesma (pl. plasmodesmata)

Answer 28

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

Question 29

pluripotent

Answer 29

capable of giving rise to any type of cell or tissue

Question 30

proteoglycan

Answer 30

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

Question 31

proto-oncogene

Answer 31

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

Question 32

stem cell

Answer 32

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

Question 33

tight junction

Answer 33

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

Question 34

tissue

Answer 34

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

Question 35

tumor suppressor gene

Answer 35

a gene that in a normal tissue cell inhibits cancerous behaviour. loss or inactivation of both copies of such a gene from a diploid cell can cause it to behave as a cancer cell

Question 36

Wnt protein

Answer 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