BIOL 443 Lecture Notes - Lecture 5: Plant Stem, Gastrulation, Multicellular Organism
Document Summary
The tgf-beta (b) superfamily: large family of paracrine factors extensively used in development. Includes the activin, bone morphogenic protein (bmp), nodal, vg1, and many other families. A wnt pathway: packaging the b-catenin destruction apparatus into endosomes: early endosome forms, fusion and internalization of destruction complex (dc, multivesicular endosome; destruction complex internalized, dc sequestered, b-catenin accumulates and can enter nucleus. The stem cell concept: stems cells can: Divide to create a new stem cell and a developmentally committed cell (single stem cell asymmetry) Stem cells populations can coordinate division and differentiation to maintain a stem cell pool (population asymmetry) Basically meaning stem cells can divide into new stem cells or differentiated cells depending on the needs of the cell pool. Stem cell potency: totipotent cells- capable of forming any tissue, including both embryonic and extra embryonic tissues. Only the first 4-8ish blastomeres are totipotent: pluripotent cells- capable of forming all the cell types of the embryo proper and adult body.
