LIFE 102 Lecture Notes - Lecture 9: Plasmodesma, Plant Cell, Protein Subunit
Document Summary
These organelles were originally derived from an ancestral prokaryotes. Membrane-bound compartments, suspended in cytosol; have defined functions. Surface structures mediating cell: cell contact and communication. A network of protein fibers extending throughout the cell. Microtubules: thick, hollow fibers composed of tubulin proteins. Motor proteins can bind microtubules, and move along them, The mitotic spindle ( cell division) carrying a cargo. Microtubules drive the motion of flagella and cilia. In animal cells, microtubules grow out from a centrosome, made up of a pair of centrioles. Microfilaments: thin, solid cables composed of actin proteins. Cell movement: actin filaments can interact with myosin filaments to generate cell contraction. Parallel myosin and actin filaments slide past each other, generating contraction of the cell overall. Actin: myosin interaction near the trailing edge squeezes the cytoplasm forward . Cytoplasmic streaming: myosin motors, attached to organelles, gently stream along the parallel actin fibers. Intermediate filaments: medium- sized , solid cables composed of keratin protein.
