LIFE 102 Lecture Notes - Centrosome, Ultrastructure, Plant Cell
Document Summary
Form a 3-d network called the cortex just inside the plasma membrane to support the cell"s shape. In many cells, microtubules grow out from a centrosome near the nucleus. In animal cells, the centrosome has a pair of centrioles, each with nine triplets of microtubules arranged in a ring. Microtubules control the beating of cilia and flagella, locomotor appendages. A core of microtubules sheathed by the plasma membrane. A basal body that anchors the cilium or flagellum. A motor protein called dynein, which drives the bending movements of a cilium or flagellum. Dynein arms alternately grab, move, and release the outer microtubules. Forces exerted by dynein arms cause doublets to curve, bending the cilium or flagellum. Concept 6. 7: extracellular components and connections between cells help coordinate cellular activities. Most cells synthesize and secrete materials that are external to the plasma membrane. The cell wall is an extracellular structure that distinguishes plant cells from animal cells.
