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BIO301: Cell Biology

Unit 3: Cell Signaling   Cells must be able to adapt to changes in the external environment. Cells in multicellular organisms must even be able to communicate with one another and cooperate in order to carry out functions. In fact, all of your body’s activities (from flexing a muscle to releasing stomach acid) rely on cellular communication or cell signaling. In this unit, we will discuss the ways in which cells talk to one another and respond to the environment. Note that this is a large and complex unit with a number of new terms.

Unit 3 Time Advisory
Completing this unit will take you approximately 19.5 hours.

☐    Subunit 3.1: 3.5 hours

☐    Subunit 3.2: 7 hours

☐    Subunit 3.4: 3.5 hours

☐    Subunit 3.5: 1.5 hours

☐    Subunit 3.6: 2 hours

☐    Assessment: 2 hours

Unit3 Learning Outcomes
Upon completion of this unit, you will be able to - distinguish between different signaling pathways; - identify the function and roles of different kinds of receptors in the cell-signaling process; - identify the function of secondary messengers and describe the mechanisms of various secondary messengers; and - describe how a synapse is transmitted at a neuromuscular junction.

3.1 Basic Types of Cell Signaling   - Reading: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: Professor Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: “Signaling Molecules and Their Receptors” Link: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: Professor Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: Signaling Molecules and Their Receptors (HTML)
 
Instructions: Read the introduction and the subsection “Modes of Cell-Cell Signaling.” This resource will cover the topics outlined in subunits 3.1.2 and 3.1.3.

 Reading this text and taking notes should take approximately 1
hour.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.
  • Lecture: University of California, Berkeley: Professor Randy Schekman’s “Cell Communication” Link: University of California, Berkeley: Professor Randy Schekman’s Cell Communication (YouTube)

    Also available in:
    iTunes U

    Instructions: Watch this lecture.

    Watching this lecture and taking notes should take approximately 2 hours.
     
    Terms of Use: This resource is released under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. It is attributed to the University of California, Berkeley and the original version can be found here.

3.1.1 Juxtacrine Signaling   - Reading: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: S.F. Gilbert’s Developmental Biology, 6e: “Juxtracrine Signaling” Link: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: S.F. Gilbert’s Developmental Biology, 6e: Juxtracrine Signaling (HTML)

 Instructions: Read the introduction and the section titled “The
Notch Pathway: Juxtaposed Ligands and Receptors.”  

 Reading this text and taking notes should take approximately 30
minutes.  

 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

3.1.2 Paracrine Signaling   This subunit is covered by the reading assigned beneath subunit 3.1. Focus on the subsection “The Modes of Cell-Cell Signaling” with associated figure (Fig. 13.1).

3.1.3 Endocrine Signaling   This subunit is covered by the reading assigned beneath subunit 3.1. Focus on the subsection “The Modes of Cell-Cell Signaling” with associated figure (Fig. 13.1).

3.2 Receptors   - Reading: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: Professor Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: “Functions of Cell Surface Receptors” Link: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: Professor Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: Functions of Cell Surface Receptors (HTML)

 Instructions: Read this section. This will cover the material in
3.2–3.3.  

 Reading this text and taking notes should take approximately 1
hour.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.
  • Lecture: University of California, Berkeley: Professor Kunxin Luo’s “Receptors” Link: University of California, Berkeley: Professor Kunxin Luo’s Receptors

    Also available in:
    iTunes U

    Instructions: Watch this lecture.

    Watching this lecture and taking notes should take approximately 2 hours.
     
    Terms of Use: This resource is released under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. It is attributed to the University of California, Berkeley and the original version can be found here.

3.2.1 G Protein-Coupled Receptors (GPCRs)   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “G Protein-Coupled Receptors” section.

3.2.2 Receptor Tyrosine Kinases (RTKs)   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the "Receptor Protein-Tyrosine Kinases” section.

3.2.3 Cytokine Receptors   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Cytokine Receptors and Nonreceptor Protein-Tyrosine Kinases” section.

3.2.4 Receptor Serine/Threonine Kinases   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Receptors Linked to Other Enzymatic Activities” section.

3.2.5 Guanylyl Cyclase Receptors   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Receptors Linked to Other Enzymatic Activities” section.

3.2.6 TNF (Tumor Necrosis Factor) Receptor Family   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Receptors Linked to Other Enzymatic Activities” section. What we now call the TNF family of receptors was first identified as a single receptor capable of inducing death in cancer cells (hence, the   name—necrosis means death). Since then, researchers have discovered a number of similar receptors, all of which have cancer-fighting properties.

3.3 Reversible Phosphorylation   3.3.1 Kinase and Phosphatase Cycle   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Receptors Linked to Other Enzymatic Activities” section.

3.3.2 Serine and Threonine Phosphorylation   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Receptors Linked to Other Enzymatic Activities”  section.

3.3.3 Tyrosine Phosphorylation   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Receptors Linked to Other Enzymatic Activities” section.

3.3.4 Regulation of Kinases and Phosphatases   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “Receptors Linked to Other Enzymatic Activities” section.

3.3.5 GTPase (Guanosine TriPhosphatase) Cycle   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “G Protein-Coupled Receptors” section.

3.3.6 Trimeric G (Guanosine) Protein Cycle   This subunit is covered by the reading assigned beneath subunit 3.2. Focus on the “G Protein-Coupled Receptors” section.

3.4 Secondary Messengers   - Reading: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: Professor Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: “Pathways of Intracellular Transduction” Link: National Center for Biotechnology Information’s Bookshelf: Sinauer Associates, Inc.: Professor Geoffrey Cooper’s The Cell: A Molecular Approach, 2e: Pathways of Intracellular Transduction (HTML)
 
Instructions: Read the introduction and the subsections “cAMP Pathway,” “Cyclic GMP,” "Phospholipids and Ca2+”, and “Ras, Raf, and the MAP Kinase Pathway.” These will cover the materials in 3.4–3.5.

 Reading this text and taking notes should take approximately 3
hours and 30 minutes.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

3.4.1 Cyclic Nucleotides   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the “cAMP Pathway: Second Messengers and Protein Phosphorylation” and “Cyclic GMP” sections. Cyclic nucleotides refer mainly to cAMP and cGMP, both of which are created by specific cyclase enzymes.

3.4.2 Lipid-Derived Secondary Messengers   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the “Phospholipids and Ca2+” section. You should know the following important classes of lipid-derived secondary messengers: phosphatidylinositol (PI), phosphatidylcholine (PC), and sphingomyelin. Each of these classes has its own set of messengers. The PI class, for example, includes inositol triphosphate (IP3) and diacylglycerol (DAG), among others.

3.4.3 Calcium   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the “Phospholipids and Ca2+” section.

3.4.4 Nitric Oxcide   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the “Cyclic GMP” section.

3.5 Integrated Signaling Pathways   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the subsections “Phospholipids and Ca2+” and “Ras, Raf, and the MAP Kinase Pathway.”

3.5.1 Light Signal Transduction inside Photoreceptor Cells   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the “Cyclic GMP” section.

3.5.2 Epinephrine and Norepinephrine Pathways inside Muscle   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the “cAMP Pathway: Second Messengers and Protein Phosphorylation” section.

3.5.3 MAPK (Mitogen-Activated Protein Kinase) Pathway   This subunit is covered by the reading assigned beneath subunit 3.4. Focus on the “Ras, Raf, and the MAP Kinase Pathway” section.

  • Lecture: University of California, Berkeley: Professor Kunxin Luo’s “The Ras-MAP Kinase Pathway” Link: University of California, Berkeley: Professor Kunxin Luo’s The Ras-MAP Kinase Pathway (YouTube)

    Also available in:
    iTunes U

    Instructions: Watch this lecture.

    Watching this lecture and taking notes should take approximately 1 hour and 30 minutes.

    Terms of Use: This resource is released under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. It is attributed to the University of California, Berkeley and the original version can be found here.

3.6 Synaptic Transmission at Neuromuscular Junction   - Lecture: University of California, Berkeley: Professor Randy Schekman’s “Synaptic Transmission” Link: University of California, Berkeley: Professor Randy Schekman’s Synaptic Transmission (YouTube)

 Also available in:  
 [iTunes
U](http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewiTunesUCollection?id=354820424)  
    
 Instructions: Watch this lecture.  

 Watching this lecture and taking notes should take approximately 2
hours.  
    
 Terms of Use: This resource is released under a [Creative Commons
Attribution-NonCommercial-NoDerivs 3.0 Unported
License](http://creativecommons.org/licenses/by-nc-nd/3.0/). It is
attributed to the University of California, Berkeley and the
original version can be found [here](http://webcast.berkeley.edu/).
  • Assessment: University of Arizona’s Biology Project: “Cell Biology” Link: University of Arizona’s Biology Project: Cell Biology (HTML)
     
    Instructions: In the “Cell Signaling” tutorial, answer questions 1–4 and 6–12.

    Completing this assessment should take approximately 1 hour.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Assessment: The Saylor Foundation's “Unit 3 Quiz” Link: The Saylor Foundation's “Unit 3 Quiz” (HTML)
     
    Instructions: Complete this quiz after working through Unit 3. The questions are either multiple-choice or matching.

    Completing this quiz should take approximately 1 hour.