largest cell on Earth?

Marco Domeniconi thedoms at mindspring.com
Wed Feb 19 00:15:43 EST 1997


lance at neuro.pharmacology.ubc.ca (Lance Corey) wrote:

>brians at interlog.com (Brian Scott) wrote:
>
>>In article <33096943.1CD7 at Bris.ac.uk>,
>>Andrew Doherty  <A.Doherty at Bris.ac.uk> wrote:
>>>> >long. Is the ostrich's egg really a single cell?!
>>>> >
>>>> 
>>>> Sure it is...isn't it?  I mean, it's an ovum and if it's fertilized
>>>> it starts dividing right?  Help me out here people!  :-)
>>>> 
>>>> Brian
>>>> 
>>>Well, I'm not so sure an ostrich egg, as such, is a single cell. Surely
>>>the ostrich ovem is the cell, which becomes the egg i.e. produces the
>>>shell, yolk sac, albumin...etc. So the ostrich egg may only contain one
>>>cell, but is not itself that cell - I think - sort of - d'ya get what I
>>>mean? I'm not sure I do, but then I'm not an ostrich biologist!!!
>>
>>
>>According to _Molecular Biolog of the Cell_ by Alberts et al.,  bird's 
>>eggs are single cells.  
>
>IMHO, I don't blieve that the whole egg is one cell; more likely, it is a
>cell surrounded by yolk and albumen.
>
>Lance Corey
>	lance at neuro.pharmacology.ubc.ca
>
>Also searching for the family names
>B A L L,    B O W E N,    B R A Y,    C O R E Y,    
>H U M P H R I E S,    H U M P H R E Y,    I V E S,    
>R E A D

According to my Cell Bio text (Alberts, etc. 3rd ed) an egg is defined
as an highly specialized cell, containing stock piles of all materials
needed for initial development of the embryo.  It is noted that
mammalian eggs do not need to as large as birds or frogs because the
embryo can take up nutrients from the mother.

I do not think it is correct to state that the ostrich egg is not a
single, large cell based on its high contents of nutrients reserves
and fats (up to 95%). If such param for the identification of a "true"
single cell was correct, then it would also exclude our own adipose
cells, among the largest in our bodies.

I do not have any ref to confirm the ostrich egg, but I recall having
read somewhere that it is indeed the largest cell.

Marco



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