What is surface-to-volume ratio?
How do I calculate them?  Does it involve plasma membrane of the cell?
Is the surface-to-volume ratio different between bacteria and
eucaryotic cells? If they are, how are they different?

Hi rrom25:

I have found the following information for you. If you need any more
information in any area, please ask using the Clarification feature.


What is surface-to-volume ratio? 
**********************

"S/V ratio refers to the amount of surface a structure has relative to
its size. Or stated in a more gruesome manner, the amount of 'skin'
compared to the amount of 'guts'."
From: http://employees.csbsju.edu/SSAUPE/biol327/sv-ratio.htm


How do I calculate them?  
**********************

"To calculate the S/V ratio, simply divide the surface area by the
volume."
From: http://employees.csbsju.edu/SSAUPE/biol327/sv-ratio.htm

More detailed instructions for real-life measurements can be found at:

QUANTITATIVE CYTOLOGICAL CHARACTERISTICS: CELLS UNDER STRESS
http://www.tiem.utk.edu/~gross/bioed/webmodules/cytology.html


Does it involve plasma membrane of the cell?
**********************

I found the following information on this topic:

"A large surface-to-volume ratio is advantageous for an organism that
acquires nutrients by absorption since there is comparatively more
absorption surface (the plasma membrane) and comparatively less of a
requirement for absorbed nutrients (the cytoplasmic volume)."
From: http://www.mansfield.ohio-state.edu/~sabedon/black04.htm


Is the surface-to-volume ratio different between bacteria and
eucaryotic cells? If they are, how are they different?
**********************

Yes, the S/V ratio of bacteria and eucaryotic cells are different.
Since eucaryotic cells are larger, they have a smaller S/V ratio.

"Animals, plants, fungi, protozoans, and algae all possess eukaryotic
cell types. Only bacteria have prokaryotic cell types....Eukaryotic
cells are generally much larger and more complex than prokaryotic. The
larger a cell, the smaller is its surface-to-volume ratio (the surface
area of a cell compared to its volume). For example, a spherical cell
2 micrometers (µm) in diameter has a surface-to-volume ratio of
approximately 3:1, while a spherical cell having a diameter of 20 µm
has a surface-to-volume ratio of around 0.3:1."
From: http://www.cat.cc.md.us/courses/bio141/lecguide/unit1/eustruct/eustruct.html


I hope that this information has been of help in your search.   
  
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websearcher-ga       
       
     
Search Strategy (on Google):
  
"surface to volume ratio"
measuring "surface to volume ratio"
plasma membrane "surface to volume ratio"
bacteria eucaryotic  "surface to volume ratio"

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Request for Answer Clarification by rrom25-ga on 07 Dec 2002 23:45 PST

Everything seems fine, but for the second part of question, I was
sking if the plasma membrane of the cell is involved with the
calculatig the S/V ratio.  For example, a liver cell has 110,00
micro-square-meter of membrane, 2% of which is plasma membrane. 
So...do we use 110,000 for surface are, or 2% of 110,000?

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Clarification of Answer by websearcher-ga on 08 Dec 2002 00:27 PST

Hi rrom25:

Thanks for the clarification request. I will research the new
information for you first-thing tomorrow. :-)

websearcher-ga

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Clarification of Answer by websearcher-ga on 08 Dec 2002 08:48 PST

Hi rrom25:

My further research (as well as some help from my fellow researcher
tehuti-ga) has shown you do indeed need to use the plasma membrane
surface area in your S/V calculations. Surface-to-volume calculations
are typically done for cells to determine the size (volume) a cell can
reach and still be supported by enough surface area to absorb
nutrients to "feed" the increased volume (since absorption occurs
through the plasma membrane).

Many eucaryotic cells have evolved folds and projections in their
plasma membranes in order to allow for more intake of nutrients. You
would need to calculate the increased surface area in these cases to
accurately reflect the S/V ratio. If a cell (such as a liver cell) has
a decreased amount of plasma membrane, then you'd need to use that
smaller value to get an accurate reflection of absorption rates.

I hope this clears things up. 

websearcher-ga 


Additional Search Strategy:

"surface-to-volume" eukaryotic folds projections 
://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&safe=off&q=%22surface-to-volume%22+eukaryotic+folds+projections