4.3 Flashcards
Identify the different cytoskeletal elements involved in cell movement.
Actin filaments and microtubules help cell movement. Some cells crawl using actin microfilaments. Eukaryotic flagella and cilia have 9+2 arrangement of microtubules. 9 microtubule pairs surrounding 2 centrals microtubules. Cilia are shorter and more numerous (green algae with flagella and paramecia with many cilia).
Compare and contrast the extracellular components of plant and animal cells.
Animal cells lack the cell wall that plants have. Animal cells instead secrete an elaborate mixture of glycoproteins into the space around them. Strong fibers of collagen and another fibrous protein, elastin, are embedded within a complex web of other glycoproteins (called proteoglycans) that form a protective layer over the cell surface.
Describe the structure of the plant cell wall.
The plant cell wall is an extracellular structure. It protects the plant cell, maintains its shape, and prevents excessive uptake of water. The plant cell walls are made up of cellulose fibers embedded in other polysaccharides and protein.
Describe the structure and function of the extracellular matrix in animal cells.
The extracellular matrix is made up of glycoproteins such as collagen, proteoglycans, and fibronectin. The ECM proteins bind to receptor proteins in the plasma membrane called integrins.
Differentiate adhesive cell junctions.
mechanically attach cytoskeletons of neighboring cells or cells to the ECM.
includes adherens junctions and desmosomes
Differentiate septate cell junctions.
aka tight junctions connect the plasma membranes of adjacent cells in a sheet.
no leak
Differentiate communicating cell junctions.
aka gap junctions chemical or electrical signal pass directly from one cell to an adjacent one.
describe plant cell junctions
specialized openings in plant cell walls
cytoplasm of adjoining cells are connected
function similar to gap junctions in animal cells
