Cell Membrane Structure and Functions
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Questions and Answers

What is the main function of cholesterol molecules in the cell membrane?

  • To maintain fluidity and structure of the membrane (correct)
  • To regulate what enters and leaves the cell
  • To facilitate cell-cell interactions
  • To form glycolipids and glycoproteins
  • What is the term for the movement of molecules down their concentration gradient?

  • Passive transport (correct)
  • Active transport
  • Receptor-mediated endocytosis
  • Facilitated diffusion
  • What is the purpose of carbohydrates attached to lipids and proteins in the cell membrane?

  • To help identify self and non-self (correct)
  • To form a barrier function
  • To regulate the movement of molecules across the membrane
  • To facilitate cell signaling
  • What is the term for the arrangement of proteins and lipids in the cell membrane?

    <p>Fluid mosaic model</p> Signup and view all the answers

    What is the function of integral proteins in the cell membrane?

    <p>To span the membrane and facilitate transport</p> Signup and view all the answers

    What is the term for the movement of molecules against their concentration gradient?

    <p>Active transport</p> Signup and view all the answers

    What is the characteristic of the cell membrane that allows certain molecules to pass through while restricting others?

    <p>Semipermeable</p> Signup and view all the answers

    What is the function of peripheral proteins in the cell membrane?

    <p>To attach to the surface of the membrane</p> Signup and view all the answers

    Study Notes

    Structure and Composition

    • Phospholipid bilayer: a double layer of lipids with hydrophilic heads and hydrophobic tails
    • Embedded proteins: integral proteins (span the membrane) and peripheral proteins (attached to the surface)
    • Cholesterol molecules: embedded between phospholipids, maintaining fluidity and structure
    • Carbohydrates: attached to lipids and proteins, forming glycolipids and glycoproteins

    Functions

    • Barrier function: regulates what enters and leaves the cell
    • Cell signaling: proteins and lipids participate in signal transduction pathways
    • Cell adhesion: proteins and carbohydrates facilitate cell-cell interactions
    • Transport: proteins facilitate movement of molecules across the membrane
    • Cell recognition: carbohydrates and proteins help identify self and non-self

    Fluid Mosaic Model

    • Fluidity: phospholipid bilayer is dynamic and flexible, allowing for movement of proteins and lipids
    • Mosaic: proteins and lipids are arranged in a mosaic pattern, with varying degrees of mobility

    Types of Transport

    • Passive transport: movement of molecules down their concentration gradient (diffusion, osmosis)
    • Active transport: movement of molecules against their concentration gradient, requiring energy input
    • Facilitated diffusion: assisted transport of molecules down their concentration gradient
    • Receptor-mediated endocytosis: uptake of molecules into the cell through receptor-mediated vesicle formation

    Membrane Permeability

    • Semipermeable: allows certain molecules to pass through, while restricting others
    • Selective permeability: specific molecules are allowed to pass through, while others are restricted
    • Permeability coefficients: measure of a molecule's ability to pass through the membrane

    Cell Membrane Structure

    • Phospholipid bilayer consists of a double layer of lipids with hydrophilic heads and hydrophobic tails
    • Integral proteins span the membrane, while peripheral proteins attach to the surface
    • Cholesterol molecules are embedded between phospholipids, maintaining fluidity and structure
    • Carbohydrates attach to lipids and proteins, forming glycolipids and glycoproteins

    Cell Membrane Functions

    • Regulates what enters and leaves the cell through barrier function
    • Participates in signal transduction pathways through proteins and lipids
    • Facilitates cell-cell interactions through proteins and carbohydrates
    • Enables movement of molecules across the membrane through proteins
    • Helps identify self and non-self through carbohydrates and proteins

    Fluid Mosaic Model

    • Phospholipid bilayer is dynamic and flexible, allowing for movement of proteins and lipids
    • Proteins and lipids are arranged in a mosaic pattern, with varying degrees of mobility

    Cell Transport

    • Passive transport: movement of molecules down their concentration gradient through diffusion and osmosis
    • Active transport: movement of molecules against their concentration gradient, requiring energy input
    • Facilitated diffusion: assisted transport of molecules down their concentration gradient
    • Receptor-mediated endocytosis: uptake of molecules into the cell through receptor-mediated vesicle formation

    Membrane Properties

    • Semipermeable: allows certain molecules to pass through, while restricting others
    • Selective permeability: specific molecules are allowed to pass through, while others are restricted
    • Permeability coefficients: measure of a molecule's ability to pass through the membrane

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    Description

    Quiz about the structure and composition of cell membranes, including phospholipid bilayer, embedded proteins, cholesterol, and carbohydrates. Learn about the functions of cell membranes, including barrier function and more.

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