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What problems do larger cells need to overcome in order to exist
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thains32
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What problems do larger cells need to overcome in order to exist? Two ways that larger cells circumvent this problem

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What problems do larger cells need to overcome in order to exist
Feb 13, 2012

They must overcome the fact that, as they get larger, their surface-to--volume ratio becomes so small that simple diffusion can't take care of their needs (there's not enough surface area for things to come and go in satisfactory quantities).



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What problems do larger cells need to overcome in order to exist
Feb 13, 2012

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They need to overcome their surface area to volume ratio , which dictates how fast required gases (like oxygen) can move into the cell and how fast metabolic wastes can move out of the cell.
They need to overcome the problem that in a large cell, there will be portions of it that are distant from the nucleus, and thus may be far from the source of new protein manufacture.

Overcoming surface area to volume ratio: Big cells are either not very active (e.g. human ovum) or not spherical. Being non-spherical is a good way of increasing surface area to volume ratio.

Overcoming the distance from the nucleus problem: Some large cells have multiple nuclei, and/or have a large nucleus with multiple copies of the genome within.



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George
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What problems do larger cells need to overcome in order to exist
Feb 13, 2012

Larger cells are fighting gravity, along with the gas-exchange limits of its membrane. Volume increases cubically, so eventually, at some size, the cell would starve.

An ostrich egg is one cell. It has a protein matrix (shell) that protects it and prevents it from spreading out over the floor.

Larger cells group together (eukaryotes) and attack the energy problem as a team. Blood basically delivers nutrients to every cell in your body, and every cell has its specific function, all of which are essential to the survival of each other.



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What problems do larger cells need to overcome in order to exist
Feb 13, 2012

Larger cells don't have a high surface area to volume ratio, so diffusion is limited. They can overcome this by using a plasma membrane that has many folds or with cilia/pili.



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