Cell-cell interactions// Mastering biology
Long fibers of protein found in the extracellular matrix that provide structural support for cells
collagen
The most abundant protein found in the extracellular matrix of animal cells is _____.
collagen
Membrane protein complexes that strengthen the adhesion between adjacent animal cells, like rivets, to protect against pulling forces; bind cells together and function as anchors for fibers in the cytoskeleton
desmosomes
The primary role of _____ is to bind animal cells together.
desmosomes
Because cell walls consist of a cross-linked network of long filaments embedded in a stiff surrounding material, they can be called _____.
fiber composites
Which statement best describes what would happen if you treated cells in a developing frog embryo with a molecule that blocked the function of a cadherin present in muscle tissue
Adhesion of muscle cells to other muscle cells would be disrupted Because each cadherin can bind only to cadherins of the same type, only adhesion of muscle cells to other muscle cells would be affected.
_____ aid in the coordination of the activities of adjacent animal cells.
Gap (communicating) junctions
how does molecular composition of a plant cell wall compares with the ECM of animal cells?
Plant cell wall fibres consist primarily of carbohydrates; ECM fibres are dominated by proteins.
Which of the following statements most accurately describes the function of plasmodesmata in plant cells or gap junctions in animal cells?
Plasmodesmata create direct connections between the cytoplasm of adjacent plant cells.
Summarize the experimental evidence in sponges showing that animal cells adhere to each other selectively.
Selective adhesion results from the presence of specific types of cell adhesion proteins in the plasma membrane, including cadherins. Each type of protein can bind only to proteins of the same type.
A polysaccharide that is used to synthesize plant cell walls, which protect cells and help maintain their shape
cellulose
Small channels that form across the plasma membranes of adjacent animal cells; especially important in intercellular communication; help coordinate activities of adjacent cells
gap junctions
Small channels between cells that are otherwise surrounded by walls; enable movement of water and solutes between plant cells
plasmodesmata
Membrane proteins that create a watertight seal between animal cells to connect them and to keep fluid from crossing barriers
tight junctions
The type of cell-cell attachment that resembles quilting, with proteins acting as stitches, is _____.
tight junctions
Which of these cell junctions form a barrier to the passage of materials?
tight junctions
