BIO 182 Chapter Notes - Chapter 28: Blastula, Cell Adhesion, Multicellular Organism
Document Summary
Single-celled organisms have to do all the functions of a multicellular organism. Individual cells in an eukaryote cannot function on their own. Some bacterial cells can live in colonies and specialize. Only eukaryotes can differentiate cells and organs. Eukaryotes don"t suffer as much in each individual cell death. Simple multicellularity is most often seen in algae. Simple multicellular organisms: cells adhere to one another, most cells could function on their own, relatively little communication between cells, most cells are in direct contact with the environment. Complex multicellular organisms: highly developed cell adhesion, communication between cells, differentiation controlled by regulatory genes, three dimensionally organized. Cells below the surface can"t get oxygen and nutrients from the environment so transport systems must be set up. Diffusion is used to transport food, oxygen, and signals throughout the organism along with the help of bulk flow. Bulk flow is active transportation while diffusion is not.
