LIFESCI 1 Lecture Notes - Lecture 5: Cell Adhesion Molecule, Crassulacean Acid Metabolism, C4 Carbon Fixation
Document Summary
From unicellular to simple multicellular to complex multicellular. Little communication or transfer of resources between cells. Little to no differentiation of specialized cell types. Most cells retain all function, including reproduction. Every cells is in contact with the external environment. Aggregation, predators cannot focus on one of them. Death of some specialized cells can harm entire organism. Coenocytic organization: one large cell with many nuclei. Highly developed mechanisms for adhesion between cells. Cell differentiation, organisation of tissues and organs. Participate in a network of genetic interaction for cell division (growth) and differentiation. Plants: growth confined to cells at tips of stems and roots (meristems) Animals: developing cells can migrate relative to each other. A small subset of cells contribute to reproduction (gametes) Cell or tissue loss can be lethal for the organism. Presence of both interior and exterior cells (3d) Earliest fossil record of complex multicellularity, soft bodied animals, 575 million years ago.
