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bio question

Discussion in 'DAT Discussions' started by issa, Aug 12, 2006.

  1. issa

    issa Senior Member
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    A sample of blood is added to a test tube
    containing a 1.6% salt solution. A short while
    later, the red blood cells are observed to be
    smaller and wrinkled in shape due to water
    loss. This indicates that

    A. red blood cells are isotonic to the 1.6%
    salt solution.
    B. red blood cells are hypertonic to the
    1.6% salt solution.
    C. red blood cells are hypotonic to the
    1.6% salt solution.
    D. the 1.6% salt solution is hypotonic to the
    red blood cells.
    E. the 1.6% salt solution is isotonic to the
    red blood cells.
     
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  3. keibee82

    keibee82 Blue_tooth...
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    B is the answer.
     
  4. GoDucks69

    GoDucks69 some dude
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    I would say the answer would be C because the salt solution obviously has a higher salt concentration than the RBCs if the cells are losing water. The answer would either be that the solution is hypertonic to the cells or the cells are hypotonic to the solution.
     
  5. Notoriousjae

    Notoriousjae DAT Rockstar
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    answer is C
    i'm using the reasoning that since the concentration in the red blood cell is lower than the salt solution water rushes out and salt solute rushes into the cell and causes it to shrivel up due to water loss
     
  6. tinman831

    tinman831 ¯\_(ツ)_/¯
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    I agree with GoDucks... The answer is C.
     
  7. '11

    '11 Member
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  8. yorkiepoo

    yorkiepoo Member
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    "A. red blood cells are isotonic to the 1.6%
    salt solution.
    B. red blood cells are hypertonic to the
    1.6% salt solution.
    C. red blood cells are hypotonic to the
    1.6% salt solution.
    D. the 1.6% salt solution is hypotonic to the
    red blood cells.
    E. the 1.6% salt solution is isotonic to the
    red blood cells."

    The answer is definately C. Here is the reasoning:

    If cell deflates that means that water has LEFT. Since it left that means that the cell's [water] was higher than the in [solution], which respectively means that the cell's [solute] was lower than the concentration in the solution, which by definition of HYPOTONIC means that cell was hypotonic.

    *** Also, if you want to elimate choices you can look at it like this:

    *cross off "A" and "E" b/c in an isotonic solution, the cell would be happy, wouldn't swell or deflate. Remember isotonic means equilibrium.

    *As for "B" and "D"... hypotonic is the OPPOSITE of hypertonic... so if you read the choices you see that "B" and "D" are actually the SAME answer (ie. they mean the same thing).... so you can eliminate "B" and "D"

    *since you elimated all those answers.. you have C.. with little need to even understand the difference of hyper- vs. hypotonic :cool:
     
  9. DonExodus

    DonExodus Dentist in Virgin Islands
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  10. Answer is A. The isotonic salt triggers class 2 H2O efflux pumps receptors on the cell surface. Thus, the cell begins to actively transport water out of the cell, and the cell shrinks in size.
     
  11. keibee82

    keibee82 Blue_tooth...
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    Answer is B.

    here is the definition of hypertonic.
    When the cytoplasm of a cell has a lower concentration of nonpenetrating
    solutes than the extracellular medium, the medium is said to be hypertonic to the cell and water will flow out of the cell.

    This is exactly what this problem is saying...
     
  12. akdental

    akdental Member
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    this explanation is saying that the medium [hence, the 1.6% salt solution] is hypertonic to the cell [RBC]. another way of saying this is the RBC is hypotonic to the 1.6% salt solution. therefore, C is the right answer. right?
     
  13. ConfusedOne

    ConfusedOne Member
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    no reasoning needed here. Blood is isotonic to a 0.9% salt solution. So in this case, since it's 1.6%, the blood cells are hypotonic to the solution. C should be the answer
     
  14. allstardentist

    allstardentist All-Star
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    I think it's C if we assume the water loss is due to passive diffusion not other stupid stuff.
     
  15. Shane41

    Shane41 Member
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    Just so you know, I am pretty sure that I had this on my real DAT. The answer should be B.

    THis is why, the cell is going through plasmolysis. It is just like a fish in a saltwater environment. It is losing water because the salt concentration is greater outside the fish. Thus, it is hypertonic. B.
     
  16. ConfusedOne

    ConfusedOne Member
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    you are right. the solution is hypertonic to the red blood cells, making the red blood cells hypotonic to the solution. Answer = C
     
  17. egots

    egots Senior Member
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    my first instinct is B, i know a lot have said C but that does not make sense b/c hypertonic is the only thing that will cause a cell to shrivel, water going from lower to higher concentration = shriveling...unless im reading it wrong C would make the RBC lyse...
     
  18. Shane41

    Shane41 Member
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    The answer is B. Go read about it in your kaplan book. It is like a fish in saltwater. The fish has less solute than the solution. The red blood cell is hypertonic.

    lets try to find the answer to this question, its bothering me because I feel that B is right...

    Ugh!
     
  19. ConfusedOne

    ConfusedOne Member
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    the answer is C. I just found the same question on a practice test. Good day
     
  20. DonExodus

    DonExodus Dentist in Virgin Islands
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    If placed in a hypotonic solution, cells will swell: think hypo = hippo.
    If the cells themselves are hypotonic, they will shrink.
     
  21. GoDucks69

    GoDucks69 some dude
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    A hypertonic solution has more solute than the cell. So if the fish you speak of has less solute than the solution how can the cell by hypertonic. If the cell is losing water that means that the solution is hypertonic to the cell. Since that is the case then the cell is hypotonic to the solution. C has to be the answer.
     
  22. keibee82

    keibee82 Blue_tooth...
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    Yes this question is kinda tricky.
    Solution is HYPERTONIC to the cell where as RBC is HYPOTONIC to the solution.
     
  23. Envision

    Envision Envisioning...
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    definitely C
     
  24. DMD to Be

    DMD to Be not luffin' this weather.
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    Can someone explain this to me? I thought it would be B. Plasmolysis occurs with hypertonic cells. This RBC is shrinking in size....isn't this plasmolysis?? In the Kaplan book, there is nothing said about shrinking when they talk about hypotonic cells, only w/ hypertonic.
     
  25. Shane41

    Shane41 Member
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    I am thinking the same thing...please explain
     
  26. Yeyyy

    Yeyyy Senior Member
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    less solute = hypotonic.
    if the fish is hyPERtonic then that means that there is more solute in the fish/RBC than the surroundings.
     
  27. Yeyyy

    Yeyyy Senior Member
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    just check wikipedia under "hypotonic"... the first line says "In biology, a hypotonic cell environment is an environment with a lower concentration of solutes than the cytoplasm of the cell"
     
  28. taloddar2002

    taloddar2002 Slacker
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    First off, i believe plasmolysis is only used to describe plant cells. The key to answering this question is first asking where the water went. In this case the water left the RBC (you know this because the cell became smaller) in order to try to dilute the solution it was placed in. In osmosis, water will always want to move to the side with the higher concentration gradient. Therefore, the solution is more concentrated than the RBC making it HYPERTONIC to the RBC. Another way of phrasing this is to say that the RBC is hypotonic to the solution. So C is the correct answer. Hope this helped some.
     
  29. egots

    egots Senior Member
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    haha boy do i feel stupid for thinkin B...if you all go back and read what it says in Kaplan when the cell has a lower concentration than the extracellular medium, THE MEDIUM is said to be hypertonic to the cell and will cause the cell to shrivel...in the kaplan book they only discuss solutions(environment)...so a hypertonic solution will have a cell that is hypotonic and a hypotonic solution will have a cell that is hypertonic...boy i got a good laugh out of that aftrer reading it right
     
  30. Shane41

    Shane41 Member
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    Thanks everyone for clarifying this. It makes a lot more sense and I am glad I got this cleared up!
     

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