The cortex of Paramecium consists of a plasma membrane and alveolar sacs, with their inner and outer alveolar membranes that limit the area in which endocytosis can easily occur to only the parasomal ...

Image of the pellicle of Opercularia coarctata. Indentations of the plasma membrane penetrate the alveolar membranes end as coated pits. These pits are also known as pellicular pores are homologous to...

In quick-freeze deep-etch preparations in which cells are slam frozen the pellicle and the plasma membrane tends to be flattened. The double rings are present but only the outer ring of IMPs stand out...

Freeze fracture of the plasma membrane and outer alveolar membrane of the pellicle of V. microstoma. The surface of Vorticella is encircled by rings which follow the septa of underlying alveoli. In th...

A live amoeba treated with the membrane-binding vital dye FM4-64 which stains the plasma membrane, contractile vacuole and other organelles. Large membrane-bounded organelles are excluded from the bro...

A high resolution view of the left side of the buccal cavity. It is covered by the plasma membrane, alveoli and a single partial layer of microtubules. Specialized cytoplasm lines the posterior end of...

The E-fracture faces of the plasma membrane and cytopharyngeal membranes are continuous but differ in appearance since the cytopharyngeal membrane is studded with IMPs while the plasma membrane has fe...

This image, produced by the freeze-fracture technique, shows regional specialization in the structure of mammalian sperm. The P-face of the plasma membrane of a guinea pig sperm tail can be divided i...

This freeze fracture micrograph shows a region of membrane from the midpiece of opossum Didelphis virginiana sperm. This region of the sperm is notable for the repeating longitudinal bands composed ...

This electron micrograph shows the P-face of a small region of membrane from the midpiece of guinea pig sperm. The changing distribution of intramembranous particles (IMPs)in this image provided some...