Friday, 22 February 2013

2.49 understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell

Unicellular organisms- including fungi and bacteria- have a large surface area to volume ratio and they are small and so the diffusion distance is short, meaning diffusion happens very quickly.

14 comments:

  1. this doesnt answer the question

    ReplyDelete
    Replies
    1. I think it does :-) In what way does it not?

      Delete
    2. it is a complex calculation of many varying factors that equate to one simple outcome = it doesnt answer the question

      Delete
  2. Thanks so much for this amazing blog!

    ReplyDelete
  3. hi thanks so much for this blog but i thought fungi were multicellular?

    ReplyDelete
    Replies
    1. some are multicellular and some are unicellular
      e.g. yeast is single celled but mushrooms are multicellular

      Delete
  4. A simple, unicellular organism (consisting of one cell) can rely on diffusion to move substances into and out of the cell. Its surface area is large compared to its volume, so nutrients and other substances can pass quickly through the membrane and around its 'body'. - google

    ReplyDelete
  5. super-useful blog BTW. Did u go to KES cuz ur checklist is word-for-word?

    ReplyDelete
  6. The Biology Syllabus has changed.... New Syllabus Blog:

    http://igcse-biology-2017.blogspot.hk

    ReplyDelete
  7. more at

    http://igcse-biology-notes.blogspot.hk/2017/06/249-understand-why-simple-unicellular.html

    ReplyDelete
  8. The answer is:

    Unicellular organisms have a high surface area to volume ratio and ,being small, naturally have a small distance of diffusion. Therefore diffusion is the most energy efficient way of moving substances in and out of the cell, as it requires no ATP.

    ReplyDelete