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Cell Membranes quiz

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  • What are the main lipid components of the cell membrane?
    The main lipid components are glycerophospholipids and sphingolipids.
  • What does it mean that the cell membrane is selectively permeable?
    It means the membrane controls what substances can enter and exit the cell.
  • How are the phospholipids arranged in the lipid bilayer?
    Phospholipids have polar heads facing the exterior and interior surfaces, with non-polar tails in the center.
  • What is the fluid mosaic model?
    The fluid mosaic model describes the cell membrane as a dynamic, fluid structure with various molecules like proteins and cholesterol embedded in the lipid bilayer.
  • Why is the cell membrane described as 'fluid'?
    Because the phospholipids do not fit closely together due to kinks in their fatty acid chains, making the membrane flexible and dynamic.
  • What does the 'mosaic' part of the fluid mosaic model refer to?
    It refers to the presence of proteins, carbohydrates, and cholesterol interspersed within the lipid bilayer.
  • What is the function of integral proteins in the cell membrane?
    Integral proteins span the entire bilayer and appear on both sides of the membrane.
  • How do peripheral proteins differ from integral proteins?
    Peripheral proteins are associated with only one side of the membrane and do not span the bilayer.
  • What role do carbohydrate side chains play in the cell membrane?
    Carbohydrate side chains project into the extracellular fluid and are involved in cell recognition and communication.
  • Where is cholesterol found in the cell membrane, and what is its function?
    Cholesterol is found within the bilayer and increases membrane strength and stability.
  • What structural feature identifies cholesterol in the membrane?
    Cholesterol is identified by its four fused ring structure.
  • What part of the phospholipid is hydrophobic?
    The non-polar tails of the phospholipid are hydrophobic.
  • What part of the phospholipid is hydrophilic?
    The polar heads of the phospholipid are hydrophilic.
  • How does the lipid bilayer contribute to selective permeability?
    The arrangement of hydrophilic heads and hydrophobic tails allows only certain substances to pass through the membrane.
  • Why do phospholipids in the membrane not fit closely together?
    They do not fit closely together because of kinks in their fatty acid chains, which increases membrane fluidity.