BIO 202: Chapter 11 - Cell Interactions (Unit 3)
cadherins
proteins that attach cytoskeletons of adjacent cells together to provide strong cell-cell adhesion
in plant cells, a polysaccharide that is used to synthesize cell walls, which protects cells and helps maintain their shape
cellulose
ECM of animal tissues: what composes the fibers and ground substance?
- fibers are protein, usually collagen - ground substance is a type of proteoglycan, a gelatinous polysaccharide
What do integrins attach to?
- inside of cytoskeleton - outside of ECM
What do cadherins attach to?
- inside of cytoskeleton - outside of other cadherins
3 stages of cell signaling
1. Reception 2. Transduction 3. Cell Response
How does the absence of a signal transduction cascade in the processing of steroid hormones affect the cellular response that is possible?
As with a signal transduction pathway, gene expression may be altered. Other types of responses, such as muscle contraction or the rapid mobilization of glucose, are not possible.
How do connective tissues resist mechanical stress?
ECM directly bears mechanical stresses of tension and compression
integrins
In animal cells, a membrane protein with two subunits that binds to ECM on the outside of cell and cytoskeleton on inside of the cell to interconnect the two (amphipathic)
Epinephrine acts as a signal molecule that attaches to _____ proteins.
G-protein-linked receptor
apoplast
In plants, the continuum of cell walls plus the extracellular spaces. Provides strength
symplast
In plants, the continuum of cytoplasm connected by plasmodesmata between cells. Coordinates behavior via exchange of materials
How does the absence of a signal transduction cascade in the processing of steroid hormones affect signal amplification?
No amplification can occur because the number of signaling molecules dictates the size of the response. Submit
epithelial tissue structure
One or more layers of densely arranged epithelial cells with very little extracellular matrix (basal lamina)
How does the absence of a signal transduction cascade in the processing of steroid hormones affect signal regulation?
Only one step is available for regulation, which includes either blocking the receptor or making it more responsive to the signaling molecule.
Predict what would happen if a mutant Ras protein was unable to exchange GDP for GTP.
The proteins downstream from Ras would not become phosphorylated
extracellular matrix (ECM)
a collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells.
desmosomes
a type of cell-cell junction in epithelial cells that are clusters of cadherins linked to intermediate filaments inside of the cell
tight junctions (animal cells)
a type of cell-cell junction in epithelial cells that bring the membranes of adjacent epithelial cells close enough together to form a seal between the cells critical in helping epithelial cells to serve a barrier function
gap junctions (animal cell's version of plasmodesmata)
a type of cell-cell junction in epithelial cells that provide small and non-permanent cytoplasmic channels between adjacent animal cells
Hemidesmosomes
anchor cells to the basal lamina
fibronectin and laminin
cell adhesion proteins in ground substance of animal cell tissues
The _______ microfibrils in plants and ______ fibrils in animals functionally resemble the _______________ in reinforced concrete. The _________ in plants and ________ in animals functionally resemble the _________
cellulose; collagen; steel rods; pectins; proteoglycans; concrete ground substance
in animal cells, long fibers of protein found inn the ECM that provides structural support for cells
collagen
in animal cells, membrane protein complexes that strengthen the adhesion between adjacent cells, like rivets, to protect against pulling forces
desmosomes
The primary role of _____ is to bind animal cells together.
desmosomes (anchoring junctions)
How do plant cells share materials?
direct cytoplasmic connections between cells allow cells int he same tissue to share materials plasmodesmata create gaps that connect the cell membranes that allow exchange of materials
In animal cells, small channels that form across the plasma membrane of adjacent cells; especially important in intercellular communication
gap junctions
_____ aid in the coordination of the activities of adjacent animal cells.
gap junctions
The cleavage of glycogen by glycogen phosphorylase releases _____.
glucose-1-phosphate
epithelial tissue cell to ECM ratio
high cell to ECM ratio
Where are protein components of the extracellular matrix synthesized?
in the rough ER
A signal molecule is also known as a(n) _____.
ligand
connective tissue cell to ECM ratio
low cell to ECM ratio
fiber composite structure
materials that are good at resisting twisting and pulling mechanical forces (tension) as well as compressive forces
How do epithelial tissues resist mechanical stress?
mechanical stresses are transmitted from cell to cell by cytoskeletal filaments anchored to cell-matrix and cell-cell adhesion sites
A bacterium lacking the receptor for responding to quorum-sensing signals would be unable to ________.
mount a coordinated response with other microbes
ground substance
part of the ECM structure that resists compression
fibers
part of the ECM structure that resists tension (twisting/pulling force)
How are plant cells combined with one another?
plant cell walls are "glued" together by the middle lamella, formed by the gelatinous pectins from adjacent cell walls growing together results in very strong interaction between cells and makes plants very rigid
in plant cells, small channels between cells that are otherwise surrounded by walls; enable movement of water and solutes between cells
plasmodesmata
Which cell junctions allow for communications between cells?
plasmodesmata and gap junctions
Plant extracellular filaments consist of _________
polysaccharides (cellulose)
Animal cell extracellular filaments consist of __________
proteins (collagen)
Extracellular filaments in both animal and plant cells:
resist pulling forces, are able to slide past each other, are crisscrossed
connective tissue structure
sparse cells in a very voluminous extracellular matrix (low cell to ECM ratio)
structure of collagen
strong material, very flexible
A fiber composite consists of cross-linked filaments that withstand ________ and a ground substance that withstands __________
tension, compression
cellulose
the fibers of a plant's ECM (provides tension resistance)
pectin
the ground substance in a plant's ECM (provides compression resistance)
In animal cells, membrane proteins that create a watertight seal between cells
tight junctions
What cell junction forms a barrier to the passage of materials?
tight junctions
What kinds of molecules pass through gap junctions in animal cells tissue?
water, ions, monomers