BIOL 1090 Lecture Notes - Lecture 21: Photographic Emulsion, Fusion Protein, Golgi Apparatus
Document Summary
Endosymbiont theory: certain organelles of eukaryotic cell have evolved from smaller prokaryotic cells who have taken up residence in the cytoplasm of a larger host cell. Components: membranous vesicles, extensive networks of membranous canals and stacks of cisternae, endoplasmic reticulum (er, golgi complex, lysosomes/vacuoles, vesicles. Shuttles material back and forth from different parts of the cell. Organelles of system are functionally distinct form one another: unique proteins, activities, dynamic structures, compartmentation and functional diversity, conserved in eukaryotes. Transportation of macromolecules through secretion and uptake. 2 main secretory (biosynthetic) pathways: constitutive: transported in secretory vesicles and continuously discharged into extracellular space, regulated: stored in membrane-bound packages which are discharged in response to stimulus. Endocytic pathways: uptake/recycling, works in inward direction, move form outer cell surface to cytoplasm. Ability to transport a synthesized protein to a specific destination in the cell (organelles, sub-cellular regions) Sorting signals encoded in amino acids are involved. Motor proteins and cytoskeletal elements are involved.