AP Bio Ch. 7 part 2 The extracellular matrix
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Tight junctions form a seal between plasma membranes of adjacent cells and create a barrier around groups of cells. Desmosomes anchor cells together strongly through keratin filaments. Gap junctions contain channels that allow cytosol and small molecules to pass between neighboring cells, enabling cell-to-cell communication important in tissues like the heart and embryos.
AP Bio Ch. 7 part 2 The extracellular matrix
- 2. The ECM of animal cells • Animals cells lack the structure and support that a cell wall provides • Have an ECM instead that provides some of the same support
- 3. Components of the ECM • Cells secrete glycoproteins – This is the main component of the ECM All 3 of these are common ECM glycoproteins
- 4. • Collagen is the most common glycoprotein in the ECM
- 5. • Proteoglycans (a glycoprotein) form a woven network outside cells • Collagen are like strong fibers that run throughout this network
- 6. • Cells are attached to the ECM by another glycoprotein: fibronectin • On one side, fibronectin is attached to proteins in the plasma membrane • On the other side, the fibronectin is attached to the glycoproteins of the ECM
- 7. Quick Think Explain the role of: •Fibronectins •Collagen fibers •Proteoglycans in the extracellular matrix
- 8. The ECM allows for cell to cell communication
- 9. Intercellular junctions • Cells in plants and animals are organized into tissues, organs, and organ systems • Cells in a tissue may adhere to each other
- 10. The Plasmodesmata of plants • Cells walls of plants are perforated with small channels called plasmodesmata • Cytosol passes through the channel, thereby connecting the two cells
- 11. • Water, solutes, even proteins and RNA can move between cells • Allows plant cells to function as a unified system, rather than isolated cells
- 13. Intercellular Junctions in Animal Cells • 3 main types of junctions between animal cells • These junctions are most common in epithelial tissue (skin, linings of organs, etc)
- 15. Tight junctions in animal cells • The plasma membranes of neighboring cells are very tightly pressed together and bound by proteins • Forms a seal or barrier around a group of cells
- 16. Desmosomes or anchoring junctions in animal cells • Like rivets that fasten cells together in strong sheets • Keratin filaments anchor these attachments in the cytoplasm
- 17. Gap junctions (or communicating junctions) in animal cells • Similar to plasmodesmata in plant cells • Provides a channel between cells that cytosol can travel through • Allows for cell to cell communication – Important in cardiac tissue and embryonic tissue
- 18. Quick Think: Summarize the role and location of each of the 3 types of intercellular junctions