L8 Cellular Transport
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Questions and Answers

What type of structure do phospholipids with small tails or a single hydrocarbon chain form?

  • Bilayer
  • Micelle (correct)
  • Liposome
  • Vesicle

    • What is the structure formed by phospholipids with bulkier tails or two hydrophobic tails?

  • Liposome (correct)
  • Vesicle
  • Bilayer
  • Micelle

    • What is the danger signal that can trigger an inflammatory reaction in surrounding cells when there are alterations in phospholipid asymmetry?

  • Phosphatidylserine exposure (correct)
  • Oxidative damage
  • Cholesterol flipping
  • Phospholipid head group changes

    • What is the main function of cholesterol in maintaining cell membrane structure?

    <p>Forming strong interactions with phospholipids (D)</p> Signup and view all the answers

    What is the structure of cholesterol?

    <p>A hydroxyl group at one end and a hydrocarbon tail at the other (D)</p> Signup and view all the answers

    What is the main function of cell membranes?

    <p>Controlling entry and exit of substances (A)</p> Signup and view all the answers

    What is the term used to describe molecules that contain both hydrophilic and hydrophobic regions?

    <p>Amphipathic (C)</p> Signup and view all the answers

    Which part of a phospholipid faces the aqueous intracellular or extracellular space?

    <p>Phosphate head group (A)</p> Signup and view all the answers

    Why do phospholipids spontaneously form lipid bilayers in an aqueous environment?

    <p>To shield hydrophobic tails from water (D)</p> Signup and view all the answers

    What type of bond attaches the two leaflets together in a lipid bilayer?

    <p>Weak noncovalent bond (B)</p> Signup and view all the answers

    What is the primary function of the plasma membrane?

    <p>To control the diffusion of substances in and out of the cell (A)</p> Signup and view all the answers

    Which of the following is NOT a major component of the plasma membrane?

    <p>Ribosomes (D)</p> Signup and view all the answers

    According to the fluid-mosaic model, the plasma membrane is in a:

    <p>Quasi-fluid state (C)</p> Signup and view all the answers

    Which of the following is NOT a function of membrane proteins?

    <p>Storing genetic information for the cell (D)</p> Signup and view all the answers

    What is the significance of Cell Adhesion Molecules (CAMs) in the plasma membrane?

    <p>They allow cells to adhere to each other or to the extracellular matrix (B)</p> Signup and view all the answers

    What happens to the fluidity of the cell membrane during hypothermia?

    <p>Decreases (B)</p> Signup and view all the answers

    How does hypothermia affect the cell membrane's permeability?

    <p>Decreases permeability (C)</p> Signup and view all the answers

    What is the role of the cell membrane in regulating traffic in and out of the cell?

    <p>Controls both entry and exit of substances (A)</p> Signup and view all the answers

    How does returning to normal body temperature affect the cell membrane's fluidity?

    <p>Fluidity increases rapidly (C)</p> Signup and view all the answers

    What could be a possible consequence of decreased cell membrane fluidity during hypothermia?

    <p>Restricted oxygen and glucose entry (C)</p> Signup and view all the answers

    How does cholesterol affect the mobility of the first few CH2 groups in the fatty acid chains in the lipid bilayer?

    <p>Decreases their mobility (C)</p> Signup and view all the answers

    At low temperatures, how does cholesterol influence the hydrocarbon chains of lipids in the membrane?

    <p>Prevents packing together and forming crystal-like structures (B)</p> Signup and view all the answers

    Which function is NOT associated with membrane fluidity?

    <p>Promotes DNA replication (C)</p> Signup and view all the answers

    In the clinical case of hypothermia, how does the patient's condition relate to the membrane's ability to adapt to environmental changes?

    <p>The membrane's flexibility helps in adapting to temperature changes (C)</p> Signup and view all the answers

    Which process is NOT supported by proper membrane fluidity?

    <p>Muscle contraction (B)</p> Signup and view all the answers

    What is the primary function of the plasma membrane?

    <p>To regulate the movement of substances in and out of the cell (C)</p> Signup and view all the answers

    What is the term used to describe molecules that contain both hydrophilic and hydrophobic regions?

    <p>Amphiphilic (C)</p> Signup and view all the answers

    Which of the following is NOT a major component of the plasma membrane?

    <p>Carbohydrates (A)</p> Signup and view all the answers

    What is one process involved in the correction of YD's hyperkalemia?

    <p>Hemodialysis to remove excess potassium from the blood (D)</p> Signup and view all the answers

    What is the main function of cholesterol in maintaining cell membrane structure?

    <p>To provide structural support and stability to the membrane (D)</p> Signup and view all the answers

    Which of the following molecules can freely diffuse across the cell membrane?

    <p>Lipid-soluble steroids (A)</p> Signup and view all the answers

    What happens to the rate of diffusion when the temperature increases?

    <p>The rate of diffusion increases (A)</p> Signup and view all the answers

    What is the direction of water movement in a hypotonic solution?

    <p>From high solute concentration to low solute concentration (C)</p> Signup and view all the answers

    What is the role of aquaporins in the cell membrane?

    <p>To facilitate the diffusion of water (A)</p> Signup and view all the answers

    What is the term used to describe the movement of molecules from a region of high concentration to a region of low concentration?

    <p>Diffusion (C)</p> Signup and view all the answers

    What is the term for the process where molecules are moved out of the cell by vesicles that fuse with the plasma membrane?

    <p>Exocytosis (C)</p> Signup and view all the answers

    Which form of endocytosis involves the cell forming an invagination to bring dissolved materials into the cell?

    <p>Pinocytosis (D)</p> Signup and view all the answers

    In which type of transport do all solutes move in the same direction 'to the inside of the cell'?

    <p>Co-transport (Symport) (C)</p> Signup and view all the answers

    What is the process used to engulf large particles such as food or bacteria into vesicles?

    <p>Phagocytosis (C)</p> Signup and view all the answers

    Which type of transport process involves moving two molecules or ions in opposite directions?

    <p>Countertransport (D)</p> Signup and view all the answers

    Which of the following statements about facilitated diffusion is correct?

    <p>Molecules move across the membrane through channel proteins without the need for energy (C)</p> Signup and view all the answers

    How does the sodium-potassium pump work?

    <p>It transports 3 sodium ions into the cell and 2 potassium ions out of the cell (A)</p> Signup and view all the answers

    What is the difference between cotransport and symport in secondary active transport?

    <p>Cotransport moves molecules in opposite directions, while symport moves them in the same direction as sodium ions (A)</p> Signup and view all the answers

    What is the role of ATP in primary active transport?

    <p>ATP provides energy for the conformational change of the carrier protein (B)</p> Signup and view all the answers

    Which of the following statements about carrier proteins is correct?

    <p>Some carrier proteins bond to molecules and drag them through the lipid bilayer (C)</p> Signup and view all the answers

    What is the primary function of the cell membrane in maintaining homeostasis?

    <p>Establishing specific ionic concentrations inside the cell (A)</p> Signup and view all the answers

    What is the primary driving force for simple diffusion across the cell membrane?

    <p>Electrochemical gradient (B)</p> Signup and view all the answers

    Which of the following is NOT a factor that is homeostatically regulated within the body?

    <p>Atmospheric pressure (A)</p> Signup and view all the answers

    What is the primary driving force for the movement of fluids between fluid compartments in the body?

    <p>Both osmotic and hydrostatic pressure (C)</p> Signup and view all the answers

    Which of the following statements about membrane transport and homeostasis is correct?

    <p>The ionic concentration differences create an electrical potential across the cell membrane (B)</p> Signup and view all the answers

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