Lecture 06

• What is the cytoskeleton often referred to as?

  Cells skeleton
• What is one of the main functions of the cytoskeleton?

  Maintains cell shape
• What does the cytoskeleton provide mechanical support for?

  Cell division and movement
• What are the four cytoskeletal networks?

  Microtubules, microfilaments, intermediate filaments

  
• What does dynamic instability refer to in microtubules?

  The ability to grow or shrink rapidly

  
• What is treadmilling in the context of actin filaments?

  Simultaneous gain and loss of actin monomers
• What are motor proteins powered by?

  Hydrolysis of ATP
• What is the primary role of kinesin motor proteins?

  Transport substances towards the positive end

  
• What is the function of dynein motor proteins?

  Transport cargo towards the negative end

  
• What are microtubules primarily made of?

  Tubulin subunits
• What is the centrosome's role in cells?

  Primary microtubule organising centre
• How do microtubules grow?

  Via polymerisation of tubulin subunits
• What happens at the plus end of a microtubule?

  It grows more quickly than the minus end
• What is a catastrophe in microtubule dynamics?

  Switch from growth to shrinking

  
• What is the role of actin filaments in non-muscle cells?

  Support a variety of structures
• How does actin filament growth occur?

  Powered by ATP at the plus end
• What happens to actin monomers when they lose a phosphate?

  They become less stable
• What is the function of myosin motor proteins?

  Move cargo along microfilaments

  
• What is the primary function of intermediate filaments?

  Provide flexible strength and stability
• What are the classes of intermediate filaments?

  Type I, II, III, IV, V
• What is the role of protofilaments in intermediate filaments?

  Enhance resistance to compression and bending
• How do intermediate filaments contribute to cell cohesion?

  Prevent acute fracture under tension
• What is the role of microtubules during cell division?

  Pull chromatin apart during mitosis
• What are the main functions of the cytoskeleton?

  • Maintain cell shape
  • Provide mechanical support for movement
  • Support intracellular transport
  • Allow cells to change shape
  • Facilitate motility and muscle contraction
• What are the components and functions of microtubules?

  Components:

  • Tubulin subunits

  
  

  Functions:

  • Mitosis
  • Cell motility
  • Intracellular transport
  • Maintenance of cell shape
• What are the components and functions of microfilaments?

  Components:

  • Actin and myosin

  
  

  Functions:

  • Determine cell surface shape
  • Control cell locomotion
  • Serve as tracks for motor proteins
• What are the components and functions of intermediate filaments?

  Components:

  • Acidic keratins
  • Basic/neutral keratins
  • Vimentin
  • Neurofilament
  • Lamins

  
  

  Functions:

  • Resist stress and deformation
  • Hold organelles in position
  • Provide flexible strength
• What are the roles of kinesin and dynein motor proteins?

  Kinesin:

  • Moves cargo towards the positive end

  
  

  Dynein:

  • Moves cargo towards the negative end

  
• What is the summary of the cytoskeleton's importance?

  • Important role in cell structure and function
  • Components include microtubules, microfilaments, and intermediate filaments
  • Dynamic instability and treadmilling are key concepts
  • Motor proteins like kinesin, dynein, and myosin are crucial for movement