A photomicrograph of a stained semi-thin section of mouse ovary, showing a maturing Graafian follicle. The ovary contains many follicles that contain immature oocytes (egg cells). The follicle is impo...

How the cell cytoplasm is spatially organized is of fundamental interest. In ordinary animal cells the cytoplasm is organized by a radial array of microtubules, called an aster. Aster microtubules are...

Lilium longiflorum (Easter Lily) pollen. This is a thin optical section through the center of the desiccated stage of the mature pollen showing autofluorescence or harmonic generation of intrinsic st...

Lilium longiflorum (Easter Lily) pollen. This is a thin optical section through the center of the desiccated stage of the mature pollen showing autofluorescence or harmonic generation of intrinsic st...

Lilium longiflorum (Easter Lily) pollen. This is a thin optical section through the center of the desiccated stage of the mature pollen showing autofluorescence or harmonic generation of intrinsic st...

Lilium longiflorum (Easter Lily) pollen. This is a thin optical section through the center of the desiccated stage of the mature pollen showing autofluorescence or harmonic generation of intrinsic st...

Lilium longiflorum (Easter Lily) pollen. This is a thin optical section through the center of the desiccated stage of the mature pollen showing autofluorescence or harmonic generation of intrinsic st...

Lilium longiflorum (Easter Lily) pollen. This is a thin optical section through the center of the desiccated stage of the mature pollen showing autofluorescence or harmonic generation of intrinsic st...

Lilium longiflorum (Easter Lily) pollen. This is a thin optical section through the center of the desiccated stage of the mature pollen showing autofluorescence or harmonic generation of intrinsic st...

At cyst formation in the 'giant' unicellular green alga Acetabularia, each cyst contains a single nucleus which subsequently undergoes several rounds of mitosis prior to gamete formation. Initially t...