Bio

• Protoplasm


  The live material in plant and animal cells
• Cytoplasm


  The large part of protoplasm surrounded the nucleus and enclosed by cytoplasmic membrane

  
• Karyoplasm


  The small part of protoplasm present inside nucleus and enclosed by nuclear membrane, also called nucleoplasm

  
• Protoplasm


  • May appear as sol or gelatinous substance depending on temperature and water content
  • Has continuous movement under microscope but particles don't actually move from place to place
  • Can compose a plasma membrane
  • Becomes solid when heated above 45°C and doesn't return to sol state until temperature declines, leading to death of organism
• Protoplasm


  • Normally colourless and semi-translucent, with viscosity similar to egg white
  • Has density greater than water
  • Contains soluble molecules/ions, insoluble solid particles, and adhesion particles
• Organic compounds in protoplasm

  Carbohydrates, Lipids, Proteins
• Inorganic compounds in protoplasm


  Salts, Water
• Protoplasm


  • Involved in metabolism (anabolic and catabolic processes)
  • Involved in reproduction and protein synthesis
  • Exhibits irritability and ability to respond to stimuli
• Cytoskeleton


  Network of protein fibers that maintain/change cell shape, secure organelles, enable cytoplasmic and vesicle movement, and allow cell movement

  
• Types of cytoskeletal fibers


  • Microfilaments
  • Intermediate filaments
  • Microtubules

  
• Microtubules


  • Long, firm, hollow cylinders made of tubulin molecules
  • Involved in intracellular transport, mitotic spindle formation, centriole/cilia/flagella structure
  • Grow longer or shorter through polymerization/depolymerization

  
• Microfilaments


  • Thin, helical filaments made of actin
  • Involved in muscle contraction, cell movement, intracellular transport, cell shape maintenance, cytokinesis, cytoplasmic streaming

  
• Intermediate filaments


  • Thick fibers not able to contract
  • Made of different proteins like vimentin, keratin, neurofilaments, lamin, desmin
  • Provide structural and mechanical support to cells

  
• Cilia and flagella


  • Cellular structures built around a core of cytoskeletal microtubules
  • Provide motive force through waving motion generated by axonemal dynein motor proteins

  
• Centrioles


  Cylindrical structures containing microtubule vanes, which together with pericentriolar material form the centrosome

  
• Kinetochore


  Protein complex that attaches to the centromere of chromosomes and enables attachment of mitotic spindle microtubules
• Motor proteins


  • Kinesins move along microtubules carrying cellular components outward
  • Dyneins move cellular components inward and power ciliary/flagellar movement
  • Myosins interact with actin to power muscle contraction and other cellular movements