Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus indicating an increase or decrease in the concentration of solutes outside the organism or cell.

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a pH stimulus with pH < 7. pH is a measure of the acidity or basicity of an aqueous solution.

The prospore membrane is a double-membraned structure that extends from the cytoplasmic face of the spindle pole bodies to encompass the spindle pole bodies and the four nuclear lobes that are formed during meiosis. It helps isolate the meiotic nuclei from the cytoplasm during spore formation and serves as a foundation for the formation of the spore walls. An example of this component is found in Schizosaccharomyces pombe.

A protuberance from a cell of an organism that reproduces by budding, which will grow larger and become a separate daughter cell after nuclear division, cytokinesis, and cell wall formation (when appropriate). The daughter cell may completely separate from the mother cell, or the mother and daughter cells may remain associated.

An endocytic patch that consists of an actin-containing structure found at the plasma membrane in cells; formed of networks of branched actin filaments that lie just beneath the plasma membrane and assemble, move, and disassemble rapidly. An example of this is the actin cortical patch found in Saccharomyces cerevisiae.

The apex of the mating projection in unicellular fungi exposed to mating pheromone; site of polarized growth.