Re: Differences between plant &animal cells, & between prokaryotic and eukaryot

Hello Laura,

This is a somewhat subjective question, but I believe that, overall, the differences 
between prokaryotic and eukaryotic cells are much greater than the differences 
between plant and animal cells.

The two major differences between plant and animal cells are 1) plants cells have 
plastids (such as the chloroplast), and 2) plant cells have a cell wall.  Otherwise, 
they are very similar.

The differences between prokaryotic and eukaryotic cells are more fundamental.  
The most obvious difference is the presence of membrane bound organelles in 
eukaryotes.  These include the nucleus, the mitochondria, the vacuole, the 
endoplasmic reticulum and Golgi apparatus.  The various organelles give 
eukaryotic cells much more complex internal structure, and allow for a more 
organized division of labor.

You can see a diagram showing the differences between plant, animal, and 
bacterial cells here: http://www.cellsalive.com/cells/3dcell.htm

Eukaryotic cells are, on average, much bigger than prokaryotic cells.  This is due in 
part to the complex structure and organization of eukaryotic cells, which allows for 
directed intracellular transport of various nutrients and other materials throughout 
the cell.  Prokaryotes rely on diffusion, which is much slower, so the cells have to 
remain small.   These two pages can give you an idea of the sizes of bacterial and 
eukaryotic cells: http://waynesword.palomar.edu/lmexer1.htm#relative http://www.bio.davidson.edu/courses/genomics/method/sizes.html


Eukaryotes also typically have much more DNA than prokaryotes.  This is because 
1)  Eukaryotes have more genes, 2) Eukaryotic genes may contain introns, adding 
to the size of individual genes, and 3) Eukaryotic genes are often separated by long 
stretches of DNA that has no known function.

The smaller size and lesser complexity of prokaryotic cells allow them to reproduce 
very quickly.  The bacteria E. coli, for example, can divide every twenty minutes 
under optimal conditions.  Baker’s yeast, one of the simplest eukaryotes, takes 90 
minutes, while more complex eukaryotic cells could take several hours.

Alex Brands