2057Views16Replies

Author Options:

biology maximum cell size Answered

what stops a cell from being extremly large?

inparticular in prokaryotic cells, like algae, where it is the cell and is not part of something bigger like a tissue or organ.

also in the way of darwins theroy of evolution, does any one know how much it appiles to algae, either all or some strains and how much they addapt and how quickly?

Discussions

Well technically noting - For example an ostrich egg is a VERY LARGE single cell. However If your asking why single cell animals don't grow big I suspect it is more to do with the food chain.

The reason cells don't get extremely large is because they are limited by the surface area to volume ratio. Cells expel waste and bring nutrients in through diffusion. Everything is trafficked through the cell membrane. If the cell is too large, the movement of materials to and from the center is too far from the surface to move effectively.

That's generally the correct argument, but there are exceptions :-)

https://www.instructables.com/community/How-big-can-a-cell-be/

i get that bit, but why does the cell try and have the lowerst surface area possible?
and could anything be done to change why it does this?

You have it backwards. The cell needs the maximum surface area possible, because of exactly what Juliedoll19 wrote.

well, for one thing there are some extremely large (eukaryotic, admittedly) cells in nature- eggs are single cells, including ostrich eggs :D

But I believe the reason other cells are small is the danger of lysis- bursting and spillage of the cytoplasm (who broke those eggs....)- it is potentially unsafe to have larger cells with comparatively thin cell membranes.

Cell membranes usually consist of just a thin layer of protein, carbohydrate etc. The reason for this is to allow for selective permeability- much more difficult on a larger scale.

The size of cells is therefore limited by the practicality of a thick cell membrane needed to make them relatively safe from being burst.

Although now that I think about it, the danger may be offset by the potentially quite thick porous cell walls of most algal cells - no idea how effectively these protect from accidental cell lysis

Just some theories, please someone tell me if my biology is way off :-)

https://www.instructables.com/community/How-big-can-a-cell-be/

Natural selection applies equally to all living things. It just depends on what environmental pressures there are.

Probably something in the DNA signals it to stop or gets triggered?