BSCI 207 Lecture Notes - Lecture 15: Programmed Cell Death, Endosperm, Gastrulation
5 Oct 2016
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Cell type specification: differentiation, cell signaling. Controlled (time, orientation, rate of division) mitosis. Three ways that proliferation can occur/be facilitated: splitting of the cytoplasm without no initial source of nourishment. Occurs in the early stages of animal embryonic development. First initial subdivisions occur simultaneously: controlled cell division with internal nutrient source. Nutrient source is the endosperm in plants and the yolk in animals: programmed cell death and recycling. Individual cells die and are engulfed by neighbors. Occur through a stereotyped series of events. Intercalation: does not occur in plants and fungi due to a cell wall. Migration: does not occur in plants and fungi due to a cell wall. Differential expansion: expansion of cells at different rates to create cell shape. Gastrulation is an example of cell move ment and differential expansion in work: embryo is in a ball called a blastula after cleavage, gastrulation takes one tissue layer and makes three: Differentiation: cells gradually lose potential during development.
