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Anatomy & Physiology: Cell Structure and Membrane Transport

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Termini in questo insieme (20)

  • What is the primary composition of the plasma membrane?
    The plasma membrane is primarily composed of phospholipids, along with cholesterol and proteins.
  • What is the fluid mosaic model of the plasma membrane?
    The fluid mosaic model describes the plasma membrane as a fluid phospholipid bilayer with embedded proteins that move laterally.
  • Name three main functions of membrane proteins.
    Channels for substances, carriers for transport, and receptors for signal recognition.
  • What is diffusion?
    Diffusion is the movement of solutes from an area of high concentration to low concentration without energy.
  • What is osmosis?
    Osmosis is the diffusion of water across a selectively permeable membrane from low to high solute concentration.
  • Define tonicity and its effect on cells.
    Tonicity describes the effect of a solution on cell volume: isotonic (no change), hypertonic (cell shrinks), hypotonic (cell swells).
  • What is the difference between simple diffusion and facilitated diffusion?
    Simple diffusion passes molecules directly through the membrane; facilitated diffusion uses protein channels or carriers.
  • What is active transport?
    Active transport moves solutes against their concentration gradient using ATP energy.
  • Describe the Na+/K+ pump function.
    The Na+/K+ pump uses ATP to move 3 Na+ out and 2 K+ into the cell, creating an electrochemical gradient.
  • What are organelles?
    Organelles are specialized structures within the cell that perform distinct functions, such as mitochondria and ribosomes.
  • What is the function of mitochondria?
    Mitochondria produce ATP through cellular respiration and have their own DNA.
  • What role do ribosomes play in the cell?
    Ribosomes synthesize proteins by translating mRNA.
  • What is the cytoskeleton?
    The cytoskeleton is a network of protein filaments that provide structural support and aid in cell movement.
  • What is the difference between chromatin and chromosomes?
    Chromatin is the loosely packed DNA in the nucleus during interphase; chromosomes are condensed DNA during cell division.
  • What is receptor-mediated endocytosis?
    A process where cells internalize molecules by binding them to receptors, forming vesicles for transport inside the cell.
  • What is exocytosis?
    Exocytosis is the process of vesicles fusing with the plasma membrane to release substances outside the cell.
  • What is the role of enzymes in the plasma membrane?
    Membrane enzymes catalyze chemical reactions at the membrane surface.
  • How do carrier proteins function?
    Carrier proteins bind specific substances and change shape to transport them across the membrane.
  • What is secondary active transport?
    Secondary active transport uses the energy from one molecule moving down its gradient to drive another molecule against its gradient.
  • What is the significance of cholesterol in the plasma membrane?
    Cholesterol stabilizes the membrane by maintaining fluidity and preventing it from becoming too rigid or too fluid.