Cytoskeleton

• Which of the following is an actin microfilament?

  The pink microfilament labeled as "Microfilament (actin)" in the image

  
• Which of the following is an intermediate filament?

  The purple intermediate filament labeled in the image

  
• Which of the following is a microtubule?

  The green microtubule labeled in the image

  
• What are the three main types of cytoskeletal filaments?

  1. Microfilaments (actin)
  2. Intermediate filaments
  3. Microtubules

  
• What is the basic unit of a microfilament?

  $G-actin$ subunits

  
• What is the main protein component of microfilaments?

  Actin

  
• What is the role of microfilaments in the cell?

  • Maintain cell shape
  • Facilitate cell motility (e.g., muscle contraction, cell migration)
  • Involved in cytokinesis
  • Support microvilli

  
• What is the basic unit of an intermediate filament?

  $Tetrameric coiled-coil$ structures

  
• What are the main functions of intermediate filaments in the cell?

  • Provide mechanical support and tensile strength to cells
  • Maintain cell shape and integrity
  • Anchor organelles
  • Form nuclear lamina

  
• What is the basic unit of a microtubule?

  $αβ-tubulin$ heterodimers

  
• What are the key functions of microtubules in the cell?

  • Maintain cell shape and rigidity
  • Facilitate intracellular transport (e.g., vesicle movement)
  • Involve in cell division (e.g., mitotic spindle)
  • Form cilia and flagella

  
• How do the different types of cytoskeletal filaments contribute to the overall structure and function of a cell?

  • Microfilaments provide dynamic support and enable motility through contraction and migration
  • Intermediate filaments offer strong, stable mechanical support and anchorage
  • Microtubules maintain cell shape, facilitate transport, and participate in cell division

  
• What are the three main structural elements of the cytoskeleton?

  Microfilaments, intermediate filaments, microtubules
• What is the width of microfilaments?

  7 nm