Transfer of Materials

Presents the membrane as important in all of the activities and organization of the whole cell and the organelles within the cell. Points out that membranes occur in layers within the cytoplasm of the cell and will serve various functions depending upon their location. Discusses diffusion through, and permeability of a membrane, and tells how the properties of a membrane depend upon what is taking place inside the cell. Models the theory of membrane structure and the fat and protein molecules contained in the membrane. Describes water's role as a raw material in photosynthesis and shows how the amount of H20 varies. Explains colloids emphasizing part played by ions in keeping them in suspension. Shows through microcinematography the passage of water through the plasma membrane illustrating both turgid and plasmolyzed cells. Relates how electrical charges on the membrane help control movement against the gradient by phosphate ions in cells in pond water.