CHAPTER 11 CELL COMMUNICATION Learning objectives An Overview of Cell Signaling 1 Describe the basic signal transduction pathway used for mating in yeast Explain the evidence that these pathways evolved before the first multicellular organisms appeared on Earth 2 Define paracrine signaling and give an example 3 Explain how plant and animal hormones travel to target cells 4 List and briefly define the three stages of cell signaling Signal Reception and the Initiation of Transduction 5 Describe the nature of a ligand receptor interaction and state how such interactions initiate a signal transduction system 6 State where signal receptors may be located in target cells 7 Compare and contrast G protein linked receptors tyrosine kinase receptors and ligand gated ion channels Signal Transduction Pathways 8 List two advantages of using a multistep pathway in the transduction stage of cell signaling 9 Explain how an original signal molecule can produce a cellular response when it may not even enter the target cell 10 Describe how phosphorylation propagates signal information 11 Explain why a single cell may require hundreds of different 12 Explain how protein phosphatases turn off signal transduction protein kinases pathways 13 Define the term second messenger Briefly describe the role of these molecules in signaling pathways 14 Describe how cyclic AMP is formed and how it propagates signal information in target cells 15 Explain how the cholera bacterium causes the symptoms of cholera by disrupting G protein signaling pathways 16 Describe how the cytosolic concentration of Ca2 can be altered and how the increased pool of Ca2 is involved with signal transduction Cellular Responses to Signals 17 Describe how signal information is transduced into cellular responses in the cytoplasm and in the nucleus 18 Describe how signal amplification is accomplished in target cells 19 Explain why different types of cells may respond differently to 20 Explain how scaffolding proteins help to coordinate a cell s the same signal molecule response to incoming signals Apoptosis 21 Describe the roles of ced 3 ced 4 and ced 9 in apoptosis during embryonic development in Caenorhabditis elegans 22 Describe the events that may trigger signals from within a cell to trigger apoptosis 23 Describe the role of apoptosis in normal development and degenerative disease in vertebrates