Biology 1401: Chapter 5 Membranes

30 Questions | Total Attempts: 390

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  • 1. 
    The plasma membrane is a thin sheet of phosphate lipid embedded with
    • A. 

      Proteins

    • B. 

      Carbohydrates

    • C. 

      Polymers

    • D. 

      Nucleotides

    • E. 

      Sodium and potassium ions

  • 2. 
    If a cell has the same concentration of dissolved molecules as of its outside environment, the cell's condition is called as being
    • A. 

      Isotonic

    • B. 

      Hypertonic

    • C. 

      Hypotonic

    • D. 

      Hydrophobic

    • E. 

      Hydrophilic

  • 3. 
    Which of the following does not influence membrane fluidity?
    • A. 

      A decrease in temperature

    • B. 

      The addition of cholesterol

    • C. 

      Hydrogen bonding of water holding the membrane together

    • D. 

      Introduction of double bonds into fatty acids

    • E. 

      An increase in temperature

  • 4. 
    A type of transport of a solute across a membrane, up its concentration gradient, using protein carriers driven by the expenditure of chemical energy is known as
    • A. 

      Osmosis

    • B. 

      Diffusion

    • C. 

      Facilitated transport

    • D. 

      Active transport

    • E. 

      Exocytosis

  • 5. 
    The cell's transactions with the environment mediated by its plasma membrane include all of the following except
    • A. 

      Ingesting food as molecules and sometimes as entire cells

    • B. 

      Returning waste and other molecules back to the environment

    • C. 

      Responding to a host of chemical cues

    • D. 

      Directing the synthesis of various food-digesting proteins

    • E. 

      Passing of messages to other cells

  • 6. 
    Which of the following properties is not true of membrane phospholipids?
    • A. 

      The hydrophobic tails are oriented towards the interior.

    • B. 

      The hydrophilic heads are oriented towards the exterior.

    • C. 

      Only the saturated fatty acids are always present.

    • D. 

      Once they are incorporated they remain in the membrane permanently.

    • E. 

      The bilayers made up of them are randomly interspersed with proteins.

  • 7. 
    The fluid nature of the membranes is attributed to a lateral movement of
    • A. 

      Protein channels.

    • B. 

      Phospholipid molecules.

    • C. 

      Antigen molecules.

    • D. 

      Pumps such as the proton pump.

    • E. 

      The entire lipid bilayer.

  • 8. 
    On the outer surface of the plasma membrane there are marker molecules that identify the cell-type. Often these molecules are
    • A. 

      ATP.

    • B. 

      Amino acids.

    • C. 

      Nucleotides.

    • D. 

      Carbohydrate chains.

    • E. 

      Inorganic ions.

  • 9. 
    Which of the following protein classes are not found as membrane proteins?
    • A. 

      Transport channels

    • B. 

      Hormones

    • C. 

      Receptors

    • D. 

      Enzymes

    • E. 

      Identify markers

  • 10. 
    The following are all functions of a typical plasma membrane except
    • A. 

      Transport of water and bulk material.

    • B. 

      Selective transport of certain molecules and material.

    • C. 

      Reception of information.

    • D. 

      Expression of cellular identify.

    • E. 

      Synthesis of DNA.

  • 11. 
    The movement of substances to regions of lower concentration is called
    • A. 

      Active transport.

    • B. 

      Diffusion.

    • C. 

      Osmosis.

    • D. 

      Pumping.

    • E. 

      Exocytosis.

  • 12. 
    If two solutions have unequal concentrations of a solute, the solution with the lower concentration is called
    • A. 

      Isotonic.

    • B. 

      Hypertonic.

    • C. 

      Hypotonic.

    • D. 

      Hypnotic.

    • E. 

      Osmosis.

  • 13. 
    In bacteria, fungi, and plants the high internal pressure generated by osmosis is counteracted by the mechanical strength of their
    • A. 

      Plasma membranes.

    • B. 

      Organelles.

    • C. 

      Cytoskeletons.

    • D. 

      Cell walls.

    • E. 

      Flagella.

  • 14. 
    The actual transport of protons by the proton pump is mediated by a transmembrane protein which undergoes a change in its
    • A. 

      Conformation.

    • B. 

      Amino acid sequence.

    • C. 

      Net charge.

    • D. 

      Solubility.

    • E. 

      Immunity.

  • 15. 
    The process often thought of as "cell eating" is
    • A. 

      Osmosis.

    • B. 

      Pinocytosis.

    • C. 

      Phangocytosis.

    • D. 

      Diffusion.

    • E. 

      Active transport.

  • 16. 
    Carrier-mediated transport is also called
    • A. 

      Facilitated diffusion.

    • B. 

      Active transport.

    • C. 

      Exocytosis.

    • D. 

      Endocytosis.

    • E. 

      Phagocytosis.

  • 17. 
    Osmosis can only occur if water travels through the
    • A. 

      Cell wall.

    • B. 

      Semi-permeable membrane.

    • C. 

      Vacuole.

    • D. 

      ER.

    • E. 

      Cytoskeleton.

  • 18. 
    The type of transport that is specific, which requires specific carrier molecules and energy is
    • A. 

      Exocytosis.

    • B. 

      Facilitated diffusion.

    • C. 

      Active transport.

    • D. 

      Endocytosis.

    • E. 

      Osmosis.

  • 19. 
    In a single sodium-potassium pump cycle, ATP is used up with the result that
    • A. 

      3 sodium ions leave and 2 potassium ions enter.

    • B. 

      1 sodium ion enters and 1 potassium ion leaves.

    • C. 

      1 sodium ion leaves and 1 potassium ion enters.

    • D. 

      3 sodium ions enter and 2 potassium ions leave.

    • E. 

      Sodium and potassium ions enter and water leaves.

  • 20. 
    The accumulation of amino acids and sugars in animal cells occurs through
    • A. 

      ATP pumps.

    • B. 

      Sodium-potassium pumps.

    • C. 

      Glucose pumps.

    • D. 

      Coupled transport.

    • E. 

      Proton pumps.

  • 21. 
    Cholesterol functions in the plasma membrane to
    • A. 

      Transport ions.

    • B. 

      Serve as an energy molecule.

    • C. 

      Maintain fluidity.

    • D. 

      Mediate steroid action.

    • E. 

      Maintain hypertension.

  • 22. 
    The Fluid Mosaic Model proposed by Singer and Nicolson in 1972 included that
    • A. 

      The cell membrane was composed of lipids and proteins.

    • B. 

      The cell membrane was composed of a phospholipid bilayer between two layers of globular proteins.

    • C. 

      The cell membrane was composed of a phospholipid bilayer with globular proteins actually inserted into the bilayer.

    • D. 

      The cell membrane was composed of a phospholipid bilayer but the polar ends of the phospholipid molecules were reversed.

  • 23. 
    Membrane proteins serve many functions. One of the functions is transportation of substances across the membrane. If a cell biologist placed cells into an environment in which a chemical has been added that blocks the function of these transport proteins, which process will be blocked?
    • A. 

      Active transport

    • B. 

      Osmosis

    • C. 

      Diffusion

    • D. 

      Phagocytosis

    • E. 

      Pinocytosis

  • 24. 
    For the process of diffusion to occur, molecules must
    • A. 

      Move from areas of high concentration to areas of lesser concentration until an equilibrium is reached.

    • B. 

      Move from areas of low concentration to areas of higher concentration until an equilibrium is reached.

    • C. 

      Remain stationary until their molecular motion allows for an equilibrium to be reached.

    • D. 

      Move from areas of high concentration to areas of lesser concentration until facilitated transport can assist the molecular equilibrium.

    • E. 

      Move from areas of high concentration to areas of lesser concentration until an equilibrium is reached by active transport.

  • 25. 
    Facilitated diffusion is an important method for cells in obtaining necessary molecules and removing other ones. Requirements for facilitated diffusion include which of the following?
    • A. 

      The carrier molecule must be specific to the molecule that is transported. The direction of movement is always with the concentration gradient, never against the gradient.

    • B. 

      The carrier molecule is nonspecific to the molecule that is transported. The direction of movement is always with the concentration gradient, never against the gradient.

    • C. 

      The carrier molecule is nonspecific to the molecule that is transported. The direction of movement is always against the concentration gradient, never with the gradient.

    • D. 

      The carrier molecule must be specific to the molecule that is transported and an ATP molecule must be attached to the specific carrier. The direction of movement is always against the concentration gradient, never with the gradient.

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