1 / 30

Pathways of Communication

Pathways of Communication. TED Video: Bacteria Communicate?. TED Video. Cell to Cell Interactions. Explain the following statement: The sum is greater than the parts. Who speaks?. Cells in constant communication Unicellular OR Multicellular. With other organisms: Cooperation

andie
Télécharger la présentation

Pathways of Communication

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pathways of Communication

  2. TED Video: Bacteria Communicate? TED Video

  3. Cell to Cell Interactions Explain the following statement:The sum is greater than the parts.

  4. Who speaks? • Cells in constant communication Unicellular OR Multicellular • With other organisms: • Cooperation • Competition • With other cells: • Cooperation • Successful survival

  5. Making the connections.. • Cells excrete layer surround membrane • The ECM! (extracellular matrix) • Aids in: • Structure • Protection Filaments resist TENSION Ground material resists COMPRESSION

  6. ECM in plants • Primary Cell Wall – initial fiber composite (cellulose microfibrils filled with pectin) • Secondary Cell Wall – secreted by some plants • Between membrane & 1º cell wall • [High] of lignin (sturdy)

  7. Layer of pectins between cell walls(or membranes) • “glues” cells • Degradation = Cell separation

  8. ECM in animals • Proteins NOT polysaccharides • Collagen = pliability • Amt varies • # surrounding cells • Cell function (Ex: elastin in lungs) • Structural properties: integral proteins bind to ECM proteins • adjacent cells can bind at common connections in ECM = increased stability

  9. Predict! What would happen if ECM-cell connection was lost? Can you think of an example? • Cells migrate • Ex: malignant cancer

  10. Reinforcement team in the Middle Lamella 2 types of reinforcers: • Tight Junctions – “quilting” formed by connecting proteins in adjacent cells • Create water tight seal • Separate solutions (ie. Stomach fluid/blood) • Dynamic

  11. Tight Junctions

  12. 2. Desmosomes – connections between cytoskeletons of adjacent cells; “bolt” cells

  13. **Cells Selectively Adhere** • Proteins involved in cell binding – cadherins cell specificity Like cells aggregate

  14. Cellular connections…

  15. Mechanisms of Communication the method behind cell “talking” near & far

  16. Close communication in PLANTS!!! • Plasmodesmata – gaps in cell wall, continuous cell membrane & plasma • Smooth ER runs through • Regulated by proteins

  17. How are these different from plasmodesmata?

  18. Close communication in ANIMALS!!! • gap junctions – holes in ECM and membrane specialized proteins admit: • H2O • aa’s • sugar • nucleotide Coordinate reactions (Ex: muscle contractions; heartbeats)

  19. Fig. 11-4 Plasma membranes Gap junctions between animal cells Plasmodesmata between plant cells (a) Cell junctions (b) Cell-cell recognition

  20. Distant communication: 4 STEPS! • Receive • Process • Respond • Terminate

  21. 1. RECEIVE • Signals are chemical “language” (hormones) • Bind/Ligand to receptors (intra- OR extracellular) Characteristics: Cell specific Dynamic – overstimulation = adaptation Potential blockage

  22. 1. PROCESS • Upon receipt, response initiation begins • 2 types: 1. Direct hormone enters binds to receptor complex enters nucleus binds to DNA directs gene expression

  23. 2. Indirect hormone binds to receptor signal transduction begins Receptor protein kinases G-proteins Both Pathways Result in: Conversion of extracellular signal to intracellular message Amplification of a message many times over

  24. G-proteins Coupled Receptors G-protein can activate an enzyme OR an effector that will go on to activate Animations<~ Watch this! Ions, larger compounds (Ex: Ca2+, cAMP)

  25. Ex: Calcium Pathway Maintaining electrical potential across membranes, cofactor for many enzymes

  26. Receptor Protein Kinases • Phosphorylation cascades amplify signal • Activated enzymes induce a signal response

  27. 3. Response • Activity within cell altered by: • Second messengers • Phosphorylation cascades

  28. 4. Deactivation • Built in systems to “turn off” • Hydrolyze GTP/ATP • Stop phosphorylation • Overstimulation

More Related