Biology Forum Cell Biology Cell Membrane

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    • #13779

      Please help me answer these. I am practising for an exam and am not sure of the answers for these questions.

      A cell is placed into a solution that has the same osmolarity. However, one
      of the ions in the solution is able to move across the membrane (the cell
      does not contain this ion). After a period of time, the solution into which
      the cell was placed would become: (1 mark)
      a) hyperosmotic
      b) hypotonic
      c) isotonic
      d) hypertonic
      e) iso-osmotic

      Is it iso-osmotic?

      Which of the following molecules is least likely to cross the plasma
      membrane? (1 mark)
      a) Steroids
      b) Fatty acid
      c) Oxygen
      d) Disaccharide <<<< This one because it’s so large?
      e) Water

      The use of probenacid, an organic acid-based drug, in the treatment of gout takes
      advantage of which of the following properties to achieve its effects?
      a. Competition
      b. Specificity
      c. Passive diffusion along a concentration gradient <<<< This one?
      d. Saturation
      e. Fick’s Law.

      Also, is Extracellular fluid?
      a) dilute salt soltn surrounding cell
      b)another name for interstitial fluid

      Analysis of the cells in the intestine reveal that they are permeable to water,
      whereas some cells in the kidney tubule are not permeable to water at all. Can you
      suggest two reasons why these two types of cells might be different (structurally) to
      each other?
      Is this about channel proteins and amount of lipid?

    • #101385


      well, as there is least, than probably yes, disaccharide (pretty huge and mainly POLAR)

      I think it is because they fulfil other aims. In the intestine they have to absorb water (and nutrients), while in the tubule they cannot get the water

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