1. In a lipid bilayer, ___________ fatty acid tails face each other within the bilayer and form a region that excludes water.
  2. What is meant by the term �fluid mosaic model�?
    It is the movement of lipids and integral proteins within the lipid bilayer.
  3. Cholesterol within membranes functions as a(n) ____________ through its interactions with both hydrophobic and hydrophilic parts of phospholipids
    temperature controller
  4. Which of the following statements about lipid bilayers is True?
    They can fuse with other bilayers.
  5. A transmembrane protein differs from other membrane proteins because it:
    completely extends through the membrane.
  6. Proteins that are destined to become associated with the inner surface of the plasma membrane are:
    made on free ribosomes in the cytoplasm.
  7. Biological membranes are normally permeable to:
    small, hydrophobic molecules.
  8. The passive movement of a substance along its concentration gradient is termed:
  9. If the concentration of solutes in a cell is less than the concentration of solutes in the surrounding fluid, then the extracellular fluid is said to be:
  10. What kind of organism reaches equilibrium?
    a dead organism.
  11. A patient who has had a severe hemorrhage accidentally receives a large transfusion of distilled water directly into a major blood vessel. You would expect this mistake to:
    have serious, perhaps fatal consequences because the red blood cells could swell and burst.
  12. A plant cell placed in a hypertonic solution will:
    undergo plasmolysis.
  13. Facilitated diffusion:
    requires a transmembrane protein.
  14. A bacterium containing sodium ions at a concentration of 0.1 mM lives in a pond that contains sodium ions at 0.005 mM. Evidently, sodium ions are entering the cell by:
    active transport.
  15. Which of the following statements about the sodium-potassium pump is true?
    It transports 3 sodium ions out of the cell in exchange for 2 potassium ions.
  16. In the cotransport of glucose and sodium ions:
    glucose molecules are transported down their concentration gradient.
  17. A human white blood cell engulfs a bacterial cell by:
  18. Receptor-mediated endocytosis:
    brings about the selective uptake of materials by enclosing them in membranous vesicles.
  19. In cells that are constantly involved in secretion, an equivalent amount of membrane must be returned to the interior of the cell for each vesicle that fuses with the plasma membrane; if this does not occur, then what would happen?
    The cell surface will keep expanding.
  20. Plasmodesmata of plant cells are functionally equivalent to ____________ of animal cells.
    gap junctions
  21. Paracrine signaling is different from other types of signaling in that the signaling molecule:
    acts on nearby cells.
  22. In classical endocrine signaling, hormones are transported to target cells:
    in interstitial fluid.
  23. A receptor on the cell surface usually has several domains. The function of the external domain is:
    holding the receptor within the membrane.
  24. Under which of the following situations would receptor down-regulation\ most likely occur?
    The concentration of a hormone is too high.
  25. When acetylcholine binds its receptor on the surface of a muscle cell, which of the following happens next?
    A sodium gate opens.
  26. The outer part of a G protein receptor binds ______, and its inner part binds _______.
    the signaling molecule; a G protein
  27. An example of a neurotransmitter that opens ligand-gated sodium channels is:
  28. When a receptor binds to its G protein, which of the following happens next?
    GDP is replaced by GTP.
  29. An example of a second messenger is:
    protein kinase A.
  30. Adenylyl cyclase catalyzes the reaction in which:
    a protein is phosphorylated.
  31. In the signal transduction pathway involving cAMP, once cAMP is formed, it then activates:
    protein kinase.
  32. A protein kinase catalyzes the reaction in which:
    a protein loses a phosphate group.
  33. In the cAMP signal transduction pathway, once a protein kinase isactivated, which of the following happens next?
    Adenylyl cyclase is activated.
  34. Calmodulin is a:
    calcium-binding protein.
  35. Most enzyme-linked receptors are:
    tyrosine kinases.
  36. The main signaling cascade for cell division and differentiation is the _______ cascade.
    MAP kinase
  37. Nitric oxide binds _________ which is ________ target cells.
    guanylyl cyclase; inside
  38. The function of scaffolding proteins is to:
    organize signal molecule complexes.
  39. Which of the following responses involves the activation of ionchannels?
    serotonin-stimulated transmission of a neural impulse
  40. When Arabidopsis thaliana is exposed to drought conditions, the concentration of abscisic acid concentration _______ which leads to the ________.
    increases; closing of stomata
  41. The ultimate source of energy for almost all living organisms is:
    the sun.
  42. An organism can exchange matter and energy with its surroundings.Thus, any change in an organism�s energy content must be balanced by a corresponding change in the energy content of the surroundings. As such, an organismis referred to as:
    an open system.
  43. Which word is defined by this phrase: A measure of disorder orrandomness?
  44. In order for a cell to maintain a high degree of order, it must:
    constantly use energy.
  45. The sum of all chemical activities taking place in an organism is:
  46. Catabolic reactions involve the:
    breakdown of large organic molecules to simple building blocks.
  47. An exergonic reaction is considered to be:
  48. A reaction with a negative value of ?G is referred to as an_________________ reaction.
  49. An endergonic reaction can proceed only if it absorbs:
    more free energy than is released by a coupled exergonic reaction.
  50. Energy stored within the molecules of ATP is in the form of ____________energy.
Card Set