lOMoARcPSD|52942330
Campbell_Biology_Summary_Intro_Biology_A_
University_of_Pennsylvania
, lOMoARcPSD|52942330
Chapter 11: Cell Communication
11.1 “External signals are converted into responses within the cell”
Evolution of Cell Signaling
Cells of the yeast Saccharyomes cerevisiae identify their mates by chemical
signaling
There are two mating types (sexes), called a and α. Cells of mating type a secrete a
chemical signal called “a factor”, while mating type α secrete α factor
Without actually entering the cells, the two mating factors cause the cells to grow
toward each other and bring about other cellular changes. The result is fusion, or
mating, of two cells of opposite type. The new a/α cell contains all of the genes of
both original cells
The process by which a signal on a cell’s surface is converted into a specific cellular
response is a series of steps called a signal transduction pathway
Local and Long-Distance Signaling
Messenger molecules are secreted by the signaling cell. Some of these travel only
short distances; such local regulators influence cells in the vicinity
Both animals and plants use chemicals called hormones for long-distance
signaling. Hormonal signaling in animals, AKA endocrine signaling, specialized
cells release hormone molecules into vessels of the circulatory system, by which
they travel to target cells in other parts of the body
Plant hormones (growth regulators) sometimes travels in vessels but more often
reach their targets by moving through cells or diffusion through the air as a gas
The Three Stages of Cell Signaling: A Preview
Campbell_Biology_Summary_Intro_Biology_A_
University_of_Pennsylvania
, lOMoARcPSD|52942330
Chapter 11: Cell Communication
11.1 “External signals are converted into responses within the cell”
Evolution of Cell Signaling
Cells of the yeast Saccharyomes cerevisiae identify their mates by chemical
signaling
There are two mating types (sexes), called a and α. Cells of mating type a secrete a
chemical signal called “a factor”, while mating type α secrete α factor
Without actually entering the cells, the two mating factors cause the cells to grow
toward each other and bring about other cellular changes. The result is fusion, or
mating, of two cells of opposite type. The new a/α cell contains all of the genes of
both original cells
The process by which a signal on a cell’s surface is converted into a specific cellular
response is a series of steps called a signal transduction pathway
Local and Long-Distance Signaling
Messenger molecules are secreted by the signaling cell. Some of these travel only
short distances; such local regulators influence cells in the vicinity
Both animals and plants use chemicals called hormones for long-distance
signaling. Hormonal signaling in animals, AKA endocrine signaling, specialized
cells release hormone molecules into vessels of the circulatory system, by which
they travel to target cells in other parts of the body
Plant hormones (growth regulators) sometimes travels in vessels but more often
reach their targets by moving through cells or diffusion through the air as a gas
The Three Stages of Cell Signaling: A Preview
