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Biology


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#61 paleopod

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Posted 25 March 2008 - 01:27 AM

it depends on how you interpret the question. If when the original cell divides into two of equal size- if that means the volume of the two cells ( the sum of both cells) equals the size of the one original cell, and 4cells of equal size also equals the volume of the original cell, then the answer is, it was full from the beginning- full of one big cell that kept dividing into smaller cells of the same volume.??
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#62 TOPHAT

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Posted 25 March 2008 - 07:00 PM

yep 11:59 although i would like to point out that even the most primative organism will never divide that fast now change that to E.coli and every 20 minutes then it would be entirely possible
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#63 Sanjurjo

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Posted 12 April 2008 - 02:57 PM

It would have to be 11:59

:D
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#64 mckenzis

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Posted 14 April 2008 - 05:32 PM

11:59 Duh :D
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#65 scififreak

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Posted 14 April 2008 - 09:35 PM

the question isn't worded very well. it still says "Let's say some primitive organisms divide themselves every minute in two equal parts which also divide the next minute and so on." 2 equal parts doesn't mean the same size as original organism.

a better wording would be "Let's say some primitive organisms divide themselves every minute in two equal parts that are the same size as the original organism, and which also divide the next minute and so on."


I disagree, cells go through division only after they have grown to their full size, they would split, then grow again, and so on, so as such stating that they are the same size as the origional isn't necessary.
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#66 mle098

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Posted 20 April 2008 - 03:19 AM

Actually - when a cell divides each cell starts out 1/2 as big. So even though the number doubles every minute - the same CAN'T be said about the size. So if the plate was full at 12:00, it was pretty much full at 11:59. Growth and division are not the same thing.

Actually, when a cell divides it starts out the same size as every other cell. The 2 cells that form are the same size as all the other cells in the body also. I think the person who wrote this comment got confused because reproductive cells have a hypoid (1/2) number of chromosomes until they met with another, then they become diploid(1). The number of chromosome does not make a difference. Also, technically, they didn't say anything about it growing. It said that the cell divides, when this happens, the cells copies itself. It is called dividing not because its gets smaller, but because it copies while it breaks apart. Cells dividing are the same as cells multiplying. That is how we grow. Because cells divide, so it is the same thing when it comes to cells. I am taking a biology class right now although they teach these things in 7th grade.
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#67 andyrew92

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Posted 15 May 2008 - 11:23 AM

Spoiler for I know
:D :D

Edited by andyrew92, 15 May 2008 - 11:24 AM.

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#68 sparx

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Posted 15 May 2008 - 02:41 PM

its realy simple actually. some people are caught up with trying to reason it out but since its a riddle u need not just a willing suspension of disbelief but also to put aside any scientific facts. in other words it doesnt matter the rate at which cells grow die or eat. this might be called biology but it is a simple math riddle. it states that the new borns here are same size. so every minute u have 1 more for every organism before at the same size hence taking up exactly twice the space. reverse the process its half the space every minute prior to any particular minute.

the starting time doesnt matter since that varies in according to the actual size of the bacteria and the pan. none of these are needed to know when it was half full since when it was full is given. thus the answer is like so many people have said: 11:59 A.M. Its not at all a complicated riddle but one of the easiest on this page. Just remember not to over think it with scientific facts and the such.
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#69 stayathomemom3

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Posted 25 July 2008 - 06:14 PM

You don't have to know what time it started. You know what time it was full (not checked and found to be full), and you know how long it takes to double the quantity of the orgs. Taking into account that new orgs are the same size as the original, the orgs. double their quantity in 1 minute, and that the end time was 12:00, the dish had to have been half as full a minute before.
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#70 raman

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Posted 03 August 2008 - 09:27 PM

11
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