Ap Biology Notes Cellular Communication
Chapter 11: Cell Communication
Cell-to-cell communication is essential in multicellular organisms. They must communicate to coordinate activities such as growth and development, and reproduction. In addition unicellular organisms communicate with each other. Signals may use light, or touch but we will focus on chemical signals.
1. External signals are converted to responses within the cell a. Evolution of cell signaling i. In yeast a cells and αcells both secrete chemicals, which can only be received by the alternate type yeast. This signals the two cells to join via fusion 1. The process by which the signal on the surface of the cell is converted to a series of steps by the cell in response is called a signal transduction pathway ii. Signal transduction pathways are very similar in yeast and in complex multicellular organisms 2. This leads scientists to believe that this pathway evolved first in ancient prokaryotes b. Local and long distance signaling iii. Local signaling 3. Adjacent cells of plants and animals may communicate through cell junctions a. Signaling substances dissolved in the cytoplasm travel between cells i. Plants = plasmodesmata ii. Animals = gap junctions 4. Animal cells may use the following b. Cell-to-cell recognition iii. Direct contact between membrane-bound cell-surface molecules iv. Important in embryonic development and immune response c. Paracrine signaling v. Uses local regulators which are released and travel only a short distance to nearby cells vi. Ex. Growth factors target nearby cells to grow and divide d. Synaptic signaling vii. Electrical signal along a nerve cell triggers a chemical release across a synapse to trigger response
Cell-to-cell communication is essential in multicellular organisms. They must communicate to coordinate activities such as growth and development, and reproduction. In addition unicellular organisms communicate with each other. Signals may use light, or touch but we will focus on chemical signals.
1. External signals are converted to responses within the cell a. Evolution of cell signaling i. In yeast a cells and αcells both secrete chemicals, which can only be received by the alternate type yeast. This signals the two cells to join via fusion 1. The process by which the signal on the surface of the cell is converted to a series of steps by the cell in response is called a signal transduction pathway ii. Signal transduction pathways are very similar in yeast and in complex multicellular organisms 2. This leads scientists to believe that this pathway evolved first in ancient prokaryotes b. Local and long distance signaling iii. Local signaling 3. Adjacent cells of plants and animals may communicate through cell junctions a. Signaling substances dissolved in the cytoplasm travel between cells i. Plants = plasmodesmata ii. Animals = gap junctions 4. Animal cells may use the following b. Cell-to-cell recognition iii. Direct contact between membrane-bound cell-surface molecules iv. Important in embryonic development and immune response c. Paracrine signaling v. Uses local regulators which are released and travel only a short distance to nearby cells vi. Ex. Growth factors target nearby cells to grow and divide d. Synaptic signaling vii. Electrical signal along a nerve cell triggers a chemical release across a synapse to trigger response