Why space cells small? Why execute they have to remain tiny in size? originally showed up on Quora: the understanding sharing network whereby compelling inquiries are answered by world with distinct insights.

You are watching: Why are most cells small and why do they have

Answer through Dave Featherstone, Professor that Biology/Neuroscience, on Quora:

Textbooks and most instructors will certainly tell you the cells must be small because they need a high ‘surface come volume’ ratio, i beg your pardon is an excellent for trading materials in between the inside and outside that cells. Yet this is probably not yes, really the size-limiting reason, since cells differ enormously in size and also surface area to volume ratios. Bacteria room tiny contrasted to animal cells, for example. And plant cells surround themselves with a cell wall surface that greatly borders exchange v the extracellular world. If exchange were limiting, then pet cells would be as tiny as bacter cells. Or pet cells without cabinet walls can be much bigger 보다 plant cells. Or tree cells v cell wall surfaces would be lot smaller.

Others could tell you the cell size is limited by diffusion rates. You can’t have actually a very big cell due to the fact that it would take too long for points to float indigenous one side of a cell to the other. However this mirrors a deep misunderstanding of how crowded the insides of cell are. Nothing just ‘floats’ around from one next of the cell to the other. Virtually nothing in cells is diffusion limited. Many things space transported approximately in cells. Also, cells can be very, really long. Neurons can be several feet long. So obviously cell are qualified of handle with big distances.

See more: 43 Out Of 50 As A Percentage, How To Use A Calculator To Figure Percentage

I think cell are small because membranes room weak. If the cell gets too big, the cell will autumn apart. Ns think this describes why bacterial cell are small — they don’t have actually much cytoskeltal ‘reinforcement’ (although they do have actually cell walls), and also why large cells can get very big. Muscle cells and also neurons have a lot of reasonably tough cytoskeleton in them. This helps hold them together, and also therefore they have the right to be fairly large. Egg cell (like chicken eggs) have actually a hard shell. And also they are an extremely big. What wake up if you cracked an egg shell?

Ultimately, ns don’t understand why cells space small. However you should an alert that i did notblindly accept what textbooks or my teacher told me. I thought around it carefully, and came up through my own idea that fits together much evidence as I deserve to think of. The following step for a scientist would certainly be to check my idea. Probably I can measure cell membrane strength for a too many of various cells and compare that to cell size? My hypothesis predicts that cell size and membrane stamin would be very correlated. Maybe I can weaken cabinet membranes in some organism and see if it it is adapted by evolving smaller sized cells?

This question originally appeared on Quora. Asking a question, gain a great answer. Learn from specialists and accessibility insider knowledge. You can follow Quora ~ above Twitter, Facebook, and also Google+. More questions:


Quora: the location to gain and also share knowledge, empowering human being to discover from others and far better understand the world.