Lipids from the erythrocyte membrane form micells and bilayers when dipersed. Freeze-fracturing of natural membranes reveal the inclusion of integral proteins. Cholesterine influences the fluidity of the inner regions of the membrane. Dynamic reciprocal interaction of lipids with integral and peripheral proteins: fluid-mosaic-model (animation). Structural elements: spectrin network, network, microfilaments and microtubuli. Protozoa (Pseudomicrothorax dubius) digesting algal filaments.