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Bell Work PowerPoint Presentation

Bell Work

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Bell Work

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  1. Bell Work • What is a centriole? • What is the nucleolus?

  2. Intro to Biology – Lecture 41 Cell Communication and Cell Movement

  3. Cell Communication • Gap Junctions • Desmosomes • Tight Junction

  4. Gap Junctions • An opening from one cell to another, between two cells that are touching. • Cytoplasm can move from one cell to another through “tunnels”.

  5. Desmosomes • Proteins that bond the membrane of one cell to its neighbor communicate. • Cells are touching, but there is not an opening.

  6. Tight Junction • Two membranes actually bonded into one. • It makes a very strong barrier between two cells. • Form solid walls to protect the contents of a cell.

  7. Microtubules • Round, tube-shaped proteins • Thick proteins that are involved in cell movement.

  8. Microtubules • Combine with the microfilaments to form the cytoskeleton of the cell.

  9. Microtubules • Combine in very specific arrangements to form cilia and flagella.

  10. Flagella and Cilia Movement • Cilia and flagellum cause movement on the cellular level.

  11. Cilia and Flagella • Structural components of the cell • Maintained by microtubules • Considered part of the cytoskeleton

  12. Cilia • Flap back and forth to help the cell move. • Can also pass objects down a “cell line”.

  13. Primary Cilia • Serve as sensory organelles

  14. Examples of Cilia • lining of the trachea (windpipe) - they sweep mucus and dirt out of the lungs • Cilia in the Fallopian tubes moves the ovum from the ovary to the uterus

  15. Flagellum • Long, thick tails. • Used for “swimming” • They whip around and sometimes twirl, pushing the cell along.

  16. Types of Flagellum • Prokaryotic • Eukaryotic • Differ in protein composition, structure, and mechanism of propulsion.

  17. Example of Flagellum • Swimming of sperm cells

  18. Microfilaments • Long, thin, and stringy proteins (mainly actin). • Work with microtubules to form the structure that allows a cell to hold its shape, move itself, and move its organelles.

  19. Microfilaments • Also found in muscle tissue (called myofibrils) • The two proteins myosin and actin work together to help the muscle cells relax and contract.

  20. Myosin and Actin • Together, they are called actomyosin. • All of the muscle cells work together to make a muscle contract.

  21. Muscles Contracting

  22. Where are Microfilaments? • Attached to proteins in the cell membrane, floating free in the cytoplasm, or connected to other filaments or tubules.

  23. How do they Cause Movement • Binding proteins allow microfilaments to push and pull on the cell membrane to help the cell move.

  24. The Cytoskeleton • All of the microfilaments and microtubules combine to form the cytoskeleton of the cell

  25. The Cytoskeleton • The cytoskeleton provides structure. • The cytoskeleton connects to every organelle and every part of the cell membrane.

  26. The Cytoskeleton • Plays important roles in both intracellular transport (the movement of vesicles and organelles, for example) and cellular division.