Chapter 11 is not that the material is so difficult, but that most of the material will be completely new to you. Cell communication is normally not covered in standard high school biology books, yet perhaps no other section of biology has grown as much as cell signaling has in the last ten years. Take your time with this section, and you will be rewarded with a knowledge base that will be most helpful in this course and courses to come. | Chapter 11 Cell Communication Overview: The Cellular Internet Cell-to-cell communication is essential for multicellular organisms. Biologists have discovered some universal mechanisms of cellular regulation. The combined effects of multiple signals determine cell response. For example, the dilation of blood vessels is controlled by multiple molecules. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Evolution of Cell Signaling A signal transduction pathway is a series of steps by which a signal on a cell’s surface is converted into a specific cellular response. Signal transduction pathways convert signals on a cell’s surface into cellular responses. Pathway similarities suggest that ancestral signaling molecules evolved in prokaryotes and were modified later in eukaryotes. The concentration of signaling molecules allows bacteria to detect population density. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Local and Long-Distance Signaling Cells in a multicellular organism communicate by chemical messengers. Animal and plant cells have cell junctions that directly connect the cytoplasm of adjacent cells. In local signaling, animal cells may communicate by direct contact, or cell-cell recognition. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Cell Signaling Plasma membranes Gap junctions between animal cells (a) Cell junctions Plasmodesmata between plant cells (b) Cell-cell recognition Figure Communication by direct contact between cells In many other cases, animal cells communicate short distances using local regulators, messenger molecules that travel only. In long-distance signaling, plants and animals use chemicals called hormones delivered via the blood. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Local and Long-Distance Signaling Local signaling Target cell Secreting cell Secretory vesicle . | Chapter 11 Cell Communication Overview: The Cellular Internet Cell-to-cell communication is essential for multicellular organisms. Biologists have discovered some universal mechanisms of cellular regulation. The combined effects of multiple signals determine cell response. For example, the dilation of blood vessels is controlled by multiple molecules. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Evolution of Cell Signaling A signal transduction pathway is a series of steps by which a signal on a cell’s surface is converted into a specific cellular response. Signal transduction pathways convert signals on a cell’s surface into cellular responses. Pathway similarities suggest that ancestral signaling molecules evolved in prokaryotes and were modified later in eukaryotes. The concentration of signaling molecules allows bacteria to detect population density. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings .
