Cell Junctions

• What are plasmodesmata?


  An open channel through the cell wall connecting adjacent plant cells
• What is the function of plasmodesmata in plant cells?


  They allow water, small solutes, and some macromolecules to pass between cells
• What is a gap junction?


  A structure consisting of membrane proteins that create pores for cytoplasmic channels
• What substances can pass through gap junctions?


  Ions, sugars, amino acids, and small molecules
• How are gap junctions similar to plasmodesmata?


  Both allow communication and passage of substances between adjacent cells
• Why are gap junctions important in certain tissues?


  They are necessary for communication between cells in heart and muscle tissues
• What are tight junctions?


  Tightly packed plasma membranes that prevent leakage of extracellular fluid
• What is the primary function of tight junctions?


  To prevent the leakage of extracellular fluid through spaces between cells
• What are desmosomes?


  Structures that function as rivets fastening cells together
• How do desmosomes anchor cells together?


  Intermediate filaments made of keratin proteins anchor desmosomes in the cytoplasm
• What are the main types of cell junctions and their functions?

  • Plasmodesmata: Connects plant cells, allowing passage of water and small solutes.
  • Gap junctions: Connects animal cells, allowing passage of ions and small molecules for communication.
  • Tight junctions: Prevents leakage of extracellular fluid between cells.
  • Desmosomes: Fastens cells together, anchored by keratin filaments.