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AP® biology unit 4 Flashcards

AP® biology unit 4
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  • What is the primary function of the cell membrane?
    To regulate the movement of substances in and out of the cell.
  • Describe the fluid mosaic model.
    A model that describes the cell membrane as a flexible layer made of lipid molecules interspersed with proteins.
  • What role do phospholipids play in the cell membrane?
    They form a bilayer that acts as a barrier to most water-soluble substances.
  • How do proteins function in the cell membrane?
    They assist in transport, act as enzymes, or serve as receptors.
  • What is passive transport?
    The movement of substances across the cell membrane without the use of energy.
  • Define osmosis.
    The diffusion of water across a selectively permeable membrane.
  • What is active transport?
    The movement of substances against their concentration gradient, requiring energy.
  • Explain the role of ATP in active transport.
    ATP provides the energy needed to move substances against their concentration gradient.
  • What is endocytosis?
    The process by which cells take in substances by engulfing them in a vesicle.
  • Describe exocytosis.
    The process by which cells expel materials using vesicles that fuse with the plasma membrane.
  • What is the function of cholesterol in the cell membrane?
    It helps to stabilize the membrane's fluidity.
  • How do glycoproteins function in the cell membrane?
    They play a role in cell recognition and signaling.
  • What is facilitated diffusion?
    The process of passive transport of molecules across a membrane via specific transmembrane proteins.
  • What is the role of aquaporins?
    They facilitate the rapid transport of water across the cell membrane.
  • Define isotonic solution.
    A solution where the concentration of solutes is equal inside and outside the cell.
  • What happens to a cell in a hypertonic solution?
    The cell will lose water and shrink.
  • What is a hypotonic solution?
    A solution with a lower concentration of solutes compared to the cell's interior.
  • What is the sodium-potassium pump?
    A type of active transport that moves sodium out of the cell and potassium into the cell.
  • How does temperature affect membrane fluidity?
    Higher temperatures increase fluidity, while lower temperatures decrease it.
  • What is the role of carrier proteins?
    They transport specific substances across the cell membrane.
  • What is the significance of membrane potential?
    It is the voltage difference across a membrane, important for nerve impulse transmission.
  • How do ion channels function?
    They allow specific ions to pass through the membrane, facilitating electrical signaling.
  • What is receptor-mediated endocytosis?
    A selective uptake of molecules into a cell by binding to a receptor.
  • What is the role of the cytoskeleton in membrane function?
    It provides structural support and helps in cell movement and transport.
  • How do lipid rafts function in the cell membrane?
    They organize the assembly of signaling molecules, influencing membrane fluidity and protein trafficking.