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Cytoskeleton

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Ali Zia Kamboh

The cytoskeleton is a network of protein filaments and tubules that gives cells their shape and allows them to move. It has three main components: microtubules, microfilaments, and intermediate filaments. Microtubules are hollow tubes involved in intracellular transport and cell division. Microfilaments made of actin help with cell movement and shape. Intermediate filaments provide structural support. Together, the cytoskeleton transports vesicles, separates chromosomes, allows muscle contraction, and maintains cell shape.

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Cytoskeleton
SUBJECT : CELL BIOLOGY • SEEN BY : Mam Mehak • Presented by : Ahmad Ahsan Ali Zia Sawaira Ahmad Kainat Khalid
“TOPIC TO BE PRESENTED” Cytoskeleton This Photo by Unknown Author is licensed under CC BY-SA
Table of Contents • Cytoskeleton Definition • A. Microtubules • B. Microfilaments • C. Intermediate Filaments • D. Microtrabecular Lattice • Functions of Cytoskeleton • References
What is Cytoskeleton • A microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence is called cytoskeleton. • The cytoskeleton gives cells structure and shape and allows them to move around.
What is Cytoskeleton • It’s also important for intracellular transport. • At least three general classes of such fibers have been identified in eukaryotic cells. • Each of these filaments is a polymer. • All three filament systems are highly dynamic, altering their organization in response to the needs of the cell.
Cytoskeleton
A. Microtubules • The thickest are the microtubules (20 nm in diameter) which consist primarily of the tubulin protein. • Each tubulin subunit is made up of one alpha and one beta-tubulin that are attached to each other, so technically tubulin is a heterodimer, not a monomer. • Since it looks like a tube, it is named as microtubule.
A. Microtubules • In a microtubule structure, tubulin monomers are linked both at their ends and along their sides (laterally). • This means that microtubules are quite stable along their lengths. • Since the tubulin subunits are always linked in the same direction, microtubules have two distinct ends, called the plus (+) and minus (-) ends.
A. Microtubules • On the minus end, alpha-tubulin is exposed, and on the plus end, beta-tubulin is exposed. • Microtubules preferentially assemble and disassemble at their plus ends.
A. Microtubules
Function of Microtubules • Transportation of water, ions or small molecules. • Cytoplasmic streaming (cyclosis). • Formation of fibers or asters of the mitotic or meiotic spindle during cell division. • Formation of the structural units of the centrioles, basal granules, cilia, and flagella.
B. Microfilaments • The thinnest are the microfilaments (7 nm in diameter) which are solid and are principally made of two intertwined strands of a globular protein called actin. • For this reason, microfilaments are also known as actin filaments.
B. Microfilaments • Actin is powered by ATP to assemble its filamentous form, which serves as a track for the movement of a motor protein called myosin. • This enables actin to engage in cellular events requiring motion such as cell division in animal cells and cytoplasmic streaming, which is the circular movement of the cell cytoplasm in plant cells.
B. Microfilaments
Function of Microfilaments • In association with myosin, microfilaments help to generate the forces used in cellular contraction and basic cell movements. • Eukaryotic cells heavily depend upon the integrity of their actin filaments in order to be able to survive the many stresses they are faced with within their environment.
Function of Microfilaments • Microfilaments play a key role in the development of various cell surface projections including filopodia, lamellipodia, and stereocilia. • The filaments are also hence involved in amoeboid movements of certain types of cells.
Function of Microfilaments • Another important function of microfilaments is to help divide the cell during mitosis (cell division). • Microfilaments aid the process of cytokinesis, which is when the cell “pinches off” and physically separates into two daughter cells.
C. Intermediate Filaments • The fibers of the middle-order are called the intermediate filaments (IFs) having a diameter of 10 nm. • Microfilaments as a part of the cytoskeleton keep organelles in place within the cell. They provide cell rigidity and shape.
C. Intermediate Filaments • They having been classified according to their constituent protein such as desmin filaments, keratin filaments, neurofilaments, vimentin, and glial filaments.
C. Intermediate Filaments
Function of Intermediate Filaments • Intermediate filaments contribute to cellular structural elements and are often crucial in holding together tissues like skin.
D. Microtrabecular Lattice • Recently, cytoplasm has been found to be filled with a three-dimensional network of interlinked filaments of cytoskeletal fibers, called a micro-trabecular lattice. • Various cellular organelles such as ribosomes, lysosomes, etc., are found anchored to this lattice. • The micro-trabecular lattice being flexible changes its shape and results in the change of cell shape during cell movement.
D. Microtrabecular Lattice
Function of Cytoskeleton The cytoskeleton is responsible for lots of important cellular functions: • It allows cells to move. • Engulf particles. • Brace themselves against pulling forces
Function of Cytoskeleton • Transport vesicles through the cytosol. • Separate chromosomes during cell division. • It allows our muscles to contract.
References 1.Verma, P. S., & Agrawal, V. K. (2006). Cell Biology, Genetics, Molecular Biology, Evolution & Ecology (1 ed.). S .Chand and company Ltd. 2.Stephen R. Bolsover, Elizabeth A. Shephard, Hugh A. White, Jeremy S. Hyams (2011). Cell Biology: A short Course (3 ed.).Hoboken,NJ: John Wiley and Sons. 3.Alberts, B. (2004). Essential cell biology. New York, NY: Garland Science Pub. 4.https://study.com/academy/lesson/microtubules-definition-functions- structure.html 5.https://courses.lumenlearning.com/boundless-biology/chapter/the- cytoskeleton/
Cytoskeleton

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Cytoskeleton

  • 2. SUBJECT : CELL BIOLOGY • SEEN BY : Mam Mehak • Presented by : Ahmad Ahsan Ali Zia Sawaira Ahmad Kainat Khalid
  • 3. “TOPIC TO BE PRESENTED” Cytoskeleton This Photo by Unknown Author is licensed under CC BY-SA
  • 4. Table of Contents • Cytoskeleton Definition • A. Microtubules • B. Microfilaments • C. Intermediate Filaments • D. Microtrabecular Lattice • Functions of Cytoskeleton • References
  • 5. What is Cytoskeleton • A microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence is called cytoskeleton. • The cytoskeleton gives cells structure and shape and allows them to move around.
  • 6. What is Cytoskeleton • It’s also important for intracellular transport. • At least three general classes of such fibers have been identified in eukaryotic cells. • Each of these filaments is a polymer. • All three filament systems are highly dynamic, altering their organization in response to the needs of the cell.
  • 8. A. Microtubules • The thickest are the microtubules (20 nm in diameter) which consist primarily of the tubulin protein. • Each tubulin subunit is made up of one alpha and one beta-tubulin that are attached to each other, so technically tubulin is a heterodimer, not a monomer. • Since it looks like a tube, it is named as microtubule.
  • 9. A. Microtubules • In a microtubule structure, tubulin monomers are linked both at their ends and along their sides (laterally). • This means that microtubules are quite stable along their lengths. • Since the tubulin subunits are always linked in the same direction, microtubules have two distinct ends, called the plus (+) and minus (-) ends.
  • 10. A. Microtubules • On the minus end, alpha-tubulin is exposed, and on the plus end, beta-tubulin is exposed. • Microtubules preferentially assemble and disassemble at their plus ends.
  • 12. Function of Microtubules • Transportation of water, ions or small molecules. • Cytoplasmic streaming (cyclosis). • Formation of fibers or asters of the mitotic or meiotic spindle during cell division. • Formation of the structural units of the centrioles, basal granules, cilia, and flagella.
  • 13. B. Microfilaments • The thinnest are the microfilaments (7 nm in diameter) which are solid and are principally made of two intertwined strands of a globular protein called actin. • For this reason, microfilaments are also known as actin filaments.
  • 14. B. Microfilaments • Actin is powered by ATP to assemble its filamentous form, which serves as a track for the movement of a motor protein called myosin. • This enables actin to engage in cellular events requiring motion such as cell division in animal cells and cytoplasmic streaming, which is the circular movement of the cell cytoplasm in plant cells.
  • 16. Function of Microfilaments • In association with myosin, microfilaments help to generate the forces used in cellular contraction and basic cell movements. • Eukaryotic cells heavily depend upon the integrity of their actin filaments in order to be able to survive the many stresses they are faced with within their environment.
  • 17. Function of Microfilaments • Microfilaments play a key role in the development of various cell surface projections including filopodia, lamellipodia, and stereocilia. • The filaments are also hence involved in amoeboid movements of certain types of cells.
  • 18. Function of Microfilaments • Another important function of microfilaments is to help divide the cell during mitosis (cell division). • Microfilaments aid the process of cytokinesis, which is when the cell “pinches off” and physically separates into two daughter cells.
  • 19. C. Intermediate Filaments • The fibers of the middle-order are called the intermediate filaments (IFs) having a diameter of 10 nm. • Microfilaments as a part of the cytoskeleton keep organelles in place within the cell. They provide cell rigidity and shape.
  • 20. C. Intermediate Filaments • They having been classified according to their constituent protein such as desmin filaments, keratin filaments, neurofilaments, vimentin, and glial filaments.
  • 22. Function of Intermediate Filaments • Intermediate filaments contribute to cellular structural elements and are often crucial in holding together tissues like skin.
  • 23. D. Microtrabecular Lattice • Recently, cytoplasm has been found to be filled with a three-dimensional network of interlinked filaments of cytoskeletal fibers, called a micro-trabecular lattice. • Various cellular organelles such as ribosomes, lysosomes, etc., are found anchored to this lattice. • The micro-trabecular lattice being flexible changes its shape and results in the change of cell shape during cell movement.
  • 25. Function of Cytoskeleton The cytoskeleton is responsible for lots of important cellular functions: • It allows cells to move. • Engulf particles. • Brace themselves against pulling forces
  • 26. Function of Cytoskeleton • Transport vesicles through the cytosol. • Separate chromosomes during cell division. • It allows our muscles to contract.
  • 27. References 1.Verma, P. S., & Agrawal, V. K. (2006). Cell Biology, Genetics, Molecular Biology, Evolution & Ecology (1 ed.). S .Chand and company Ltd. 2.Stephen R. Bolsover, Elizabeth A. Shephard, Hugh A. White, Jeremy S. Hyams (2011). Cell Biology: A short Course (3 ed.).Hoboken,NJ: John Wiley and Sons. 3.Alberts, B. (2004). Essential cell biology. New York, NY: Garland Science Pub. 4.https://study.com/academy/lesson/microtubules-definition-functions- structure.html 5.https://courses.lumenlearning.com/boundless-biology/chapter/the- cytoskeleton/