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Cell Structure and Membrane Transport in Anatomy & Physiology

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Terms in this set (21)

  • What are the three main parts of a cell?

    Plasma membrane, cytoplasm (including cytosol and organelles), and nucleus.

  • What is the primary function of the plasma membrane?

    It acts as a physical barrier, controls entry and exit of ions, nutrients, wastes, responds to environment, and provides structural support.

  • What is the composition of the plasma membrane?

    A fluid phospholipid bilayer with cholesterol and membrane proteins (transmembrane and peripheral), plus membrane carbohydrates like glycoproteins and glycolipids.

  • Define selectively permeable membrane.

    A membrane that allows some substances to pass while blocking others based on factors like size, charge, and solubility.

  • What factors affect membrane permeability?

    Temperature, particle size, electrical charge, polarity, and solubility (lipid or water soluble).

  • What is passive transport?

    Movement of particles from high to low concentration without energy expenditure.

  • What is active transport?

    Movement of particles from low to high concentration requiring energy (ATP).

  • Explain diffusion.

    Movement of solutes from an area of high concentration to low concentration until equilibrium is reached.

  • What is osmosis?

    Diffusion of water across a selectively permeable membrane toward the area of higher solute concentration.

  • What is osmotic pressure?

    The 'pulling' pressure that draws water toward the solution with the highest solute concentration.

  • Describe isotonic solutions and their effect on cells.

    Solutions with equal solute concentration to the cell, causing no change in cell volume.

  • Describe hypotonic solutions and their effect on cells.

    Solutions with lower solute concentration than the cell, causing water to move in, cells swell and may lyse.

  • Describe hypertonic solutions and their effect on cells.

    Solutions with higher solute concentration than the cell, causing water to move out, cells shrink and crenate.

  • What is carrier-mediated transport?

    Transport where membrane proteins bind and carry solutes across the membrane, including facilitated diffusion and active transport.

  • What is facilitated diffusion?

    Passive transport using carrier proteins to move solutes from high to low concentration without ATP.

  • What is the sodium-potassium pump?

    An active transport pump that moves Na+ out of and K+ into the cell using ATP, maintaining ion balance and membrane potential.

  • What is vesicular transport?

    Transport of large molecules using vesicles and ATP, including exocytosis and endocytosis.

  • Define exocytosis.

    Process where cells expel secretions or wastes by vesicles fusing with the plasma membrane.

  • Define endocytosis and its types.

    Process of taking in substances by vesicle formation; types include phagocytosis (cell eating), pinocytosis (cell drinking), and receptor-mediated endocytosis.

  • What is phagocytosis?

    Endocytosis where cells engulf large particles or cells, important in immune response.

  • What is pinocytosis?

    Endocytosis where cells ingest extracellular fluid and solutes.