Cell Physiology

Thought Questions for Exam 2

Hao Nguyen


1.   Why are there so many types of cell-to-cell and cell-to-matrix interaction?  What is the function of each type?  What would happen if one or two types were missing?  Are these interactions specific for different types of cell or are they found in all eukaryotic cells?


2.   What are the different ways that one cell can communicate with another cell?  What are the different types of molecule required for the communication?  How does a target cell process information received from a signaling cell?  What do these target cells actually do after receiving these signals?


3.   For cells in culture, how does focal contact affect cell proliferation?


4.   What is the advantage of having one kinase receptor being able to activate multiple pathways?


5.   How are cell in culture induced to grow (or undergo cell proliferation)?  Discuss all pathways that are involved (that are discussed in class so far).


6.   What are the functions of:  Ion-channel receptor, G-protein-linked receptor, Receptor Tyrosine Kinase, and Kinase-linked receptor?  What is/are the ultimate goal of pathways that activated by these receptors?  How are these receptors controlled/activated?  How do these various pathways interact with one another?


7.   Why are there so many steps and regulations during the MAP kinase signal transduction pathway?  What is the function of each protein or enzyme?  What might     happen if one were missing?  What is the function of GAP?  Why is this function necessary?  What might happen to the cell if GAP were missing?


8.   What processes or pathways are affected if all G proteins (or GTPase) are rendered nonfunctional?  Why?  Is there any way to get around this problem?  What is the difference between phosphorylation and an exchange of GDP for GTP?


9.   How does a cell know when to perform a particular function?


10.  How do the various signal transduction pathways interact with one another?  Why do they interact with one another?


11.  What is the function these processes:  dimerization of a membrane receptor, hydrolysis of GTP, and autophosphorylation of the EGF receptor dimer.


12.  Compare and contrast the activities and functions of the Endocrine system, Paracrine system, and Autocrine system.


13.  Discuss the role of microfilaments in the growth of cells in culture.  What is/are required for the process of microfilament polymerization?  Experimentally, what can a researcher do to regulate (i.e. induce or inhibit) cell proliferation in culture?


14.  Discuss the role of microfilaments in cell-to-cell and cell-to-extracellular matrix interaction.