When yeast cells of opposite mating types are in close proximity, cell changes occur inside those cells that result in the polymerization of actin filaments, allowing the yeast cells to mate. Those changes in cell behavior are initially due to signaling molecules (pheromones) released by the yeast cells. Pheromones are ________.
A) a type of steroid hormone that diffuses through the plasma membrane causing cytoplasmic actin proteins to form filaments
B) a type of hormone that binds cell-surface receptors causing cytoplasmic actin proteins to form filaments
C) signaling molecules that bind cell-surface receptors causing yeast cells to become motile, insuring mating success
D) signaling molecules that cause the extracellular matrix of yeast cells to thicken in preparation for cell fusion
E) signaling molecules that cause intracellular G-proteins to be inhibited

Question

Quizplus · Accepted Answer

Pheromones are signaling molecules that bind to cell-surface receptors, triggering a signaling cascade inside the cell. In this case, the pheromones released by yeast cells of opposite mating types bind to receptors on the surface of adjacent cells, initiating changes in cell behavior that ultimately result in mating. These changes include the polymerization of actin filaments, which allows the cells to move towards each other and fuse.

When Yeast Cells of Opposite Mating Types Are in Close