Symplast
________ is a continuous network of cytoplasm connected by plasmodesmata.
Cadherins
________ are the linking proteins in desmosomes.
ground substance
The ________ that surrounds collagen and other fibrous components of the ECM contains highly glycosylated, gel forming proteins called proteoglycans.
Expansins
________ disrupt the hydrogen bonds that crosslink microfibrils to other polymers in the wall, loosening the structure and allowing the microfibrils to slide past one another.
Hormones
________ are information- carrying molecules that are secreted by plant and animal cells into bodily fluids and act on distant target cells.
Desmosome
________ is a strong cell- cell attachment particularly common in animal epithelial cells and certain muscle cells.
immune response
An antibody is a protein produced by a(n) ________ that binds specifically to a unique type of molecule, often another protein.
gelatinous polysaccharides
The spaces between microfibrils are filled with ________ such as pectins- the molecules that are used to thicken jams and jellies.
signal receptor
A(n) ________ is a protein that changes its shape and activity after binding to a signaling molecule.
tissue
A(n) ________ consists of similar cells that function as a unit.
Materials
________ and structures that bind cells together are particularly important in epithelial- tissues that form external and internal surfaces.
Apoplast
________ is the region outside the plasma membrane.
tight junction
A(n) ________ is a cell- cell attachment composed of specialized proteins in the plasma membranes of adjacent animal cells.
eukaryotic microbes
The use of signaling pathways to respond to population density in prokaryotic and ________ is referred to as quorum sensing.
basis of multicellularity
Direct physical connections between cells are the ________.
Membrane proteins
________ called integrins bind to extracellular cross- linking proteins, including laminins, which in turn bind to other components of the ECM.
Second messenger
________ is a small, nonprotein signaling molecule or ion that elicits an intracellular response to the first messenger.
Protein kinases
________ are enzymes that activate or inactivate other proteins by adding a phosphate group to them.
Signal transduction
________ is the conversion of a signal from one form to another.
peripheral membrane proteins
Many signal receptors span the plasma membrane and are closely associated with ________ inside the cell called G proteins.