Guest Posted December 13, 2007 Report Share Posted December 13, 2007 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. try reading the puzzle first without changing it to fit your own stupidity. This wasn't even a logic problem. They give you the answer right in the question. Anyone who didn't get this one has got some serious IQ issues. Link to comment Share on other sites More sharing options...
Guest Posted December 14, 2007 Report Share Posted December 14, 2007 depends on when the organisms started dividing or when they were put in the bowl Link to comment Share on other sites More sharing options...
Guest Posted December 14, 2007 Report Share Posted December 14, 2007 11:59 it doubles every minute Link to comment Share on other sites More sharing options...
Guest Posted January 14, 2008 Report Share Posted January 14, 2008 a cell is half as big as it was when it divides, but there's two of them, so the time stays the same. However, it increases in size, so it would be half full at 11:59, but also shortly before. However, there is no way of telling that it takes exactly a minute to reproduce, so there is no definite answer Link to comment Share on other sites More sharing options...
Guest Posted February 7, 2008 Report Share Posted February 7, 2008 I really like this brain teaser because it isn't as easy as it seems and looks. I agree with the last person's post; aside from all of the complications resulting from nutrition of these organisms, the dish was half-full at 11:59:00 and less than a minute prior to that. So, that also means that the dish was full at 12:00:00 and less than a minute before that time. Since the cell has to double in size before dividing (according to mitosis), in a perfect world there are two times when the dish is full and empty - just before the organism splits and just after division. Link to comment Share on other sites More sharing options...
Guest Posted February 13, 2008 Report Share Posted February 13, 2008 11:59. If it doubles itself eeach minute, then at 11:59 it is half the size it will be at 12:00. Link to comment Share on other sites More sharing options...
Guest Posted March 18, 2008 Report Share Posted March 18, 2008 this is so easy.and im a 5th grader11:59 to easy Link to comment Share on other sites More sharing options...
Guest Posted March 18, 2008 Report Share Posted March 18, 2008 Yeah, seriously - just read the riddle and take it at face value. I am a molecular biologist and I'm not going to get all anal on wording. I mean, how many cells actually go through a full cell cycle in one minute?? It's like going to the movies and watching a movie like "Braveheart" for historical accuracy. IT'S AN AWESOME MOVIE, but I don't really think everything in that movie was right. On top of it, had the movie had been made completely accurate, would it have been as good? Probably not - same on the riddle. If you start adding 3 million caveats, it gets confusing and not as fun to read. Purpose of these are for FUN, not to TRY to look smart by pointing out esoteric facts that are obviously not meant to be incorporated into the puzzle. Link to comment Share on other sites More sharing options...
Guest Posted March 18, 2008 Report Share Posted March 18, 2008 11:59. -1 minute = -1/2 of the cells. Link to comment Share on other sites More sharing options...
Guest Posted March 20, 2008 Report Share Posted March 20, 2008 But guys, it's a logic puzzle, not an AP Bio question. It’s asking you to look at a problem as a system of variables- ‘real world’ issues aren’t meant to apply, because that would take the logical reasoning out of the problem. Running to your text book to find out the growth rate of the common cell/ organism and it’s food consumption defeats the purpose of basic reasoning skills. Link to comment Share on other sites More sharing options...
Guest Posted March 25, 2008 Report Share Posted March 25, 2008 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.?? Link to comment Share on other sites More sharing options...
Guest Posted March 25, 2008 Report Share Posted March 25, 2008 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 Link to comment Share on other sites More sharing options...
Guest Posted April 12, 2008 Report Share Posted April 12, 2008 It would have to be 11:59 Link to comment Share on other sites More sharing options...
Guest Posted April 14, 2008 Report Share Posted April 14, 2008 11:59 Duh Link to comment Share on other sites More sharing options...
Guest Posted April 14, 2008 Report Share Posted April 14, 2008 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. Link to comment Share on other sites More sharing options...
Guest Posted April 20, 2008 Report Share Posted April 20, 2008 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. Link to comment Share on other sites More sharing options...
Guest Posted May 15, 2008 Report Share Posted May 15, 2008 (edited) 11.59 am Edited May 15, 2008 by andyrew92 Link to comment Share on other sites More sharing options...
Guest Posted May 15, 2008 Report Share Posted May 15, 2008 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. Link to comment Share on other sites More sharing options...
Guest Posted July 25, 2008 Report Share Posted July 25, 2008 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. Link to comment Share on other sites More sharing options...
Guest Posted August 3, 2008 Report Share Posted August 3, 2008 11 Link to comment Share on other sites More sharing options...
Guest Posted April 6, 2009 Report Share Posted April 6, 2009 (edited) So, I am going to take a stab at this, and there is no guarantee that this is right because it has been a few years but here it goes: .5/43=x/60 to solve for X the equation read: (I used the * as a multiplication symbol so as not to be confusing) 60/60 * .5/43 = x/60 * 60/60 30/2580 = X 3/258 = X 3/258 = .01 per minute .04 *43 min = .43 (which is half) .43 * 2 = .86 to be full So, it would take 86 minutes from start to finish to be full So, 12:00 + 86 minutes = 1:26 So, at 1:26 the dish should be full. Any chance that is close to right? Edited April 6, 2009 by cari2483 Link to comment Share on other sites More sharing options...
Guest Posted April 6, 2009 Report Share Posted April 6, 2009 Wait...I just thought about it and realized I did all that work for nothing LOL. If the dish was half way full at 12:43 and every minute, the organisms double, then at 12:44 the dish should be full...right? Like I said in the previous post, it has been a while and the scientific size of the organism aside I still didn't see how 11:59 could have been the right answer, even after reading all of the posts. Link to comment Share on other sites More sharing options...
rookie1ja Posted April 6, 2009 Author Report Share Posted April 6, 2009 Wait...I just thought about it and realized I did all that work for nothing LOL. If the dish was half way full at 12:43 and every minute, the organisms double, then at 12:44 the dish should be full...right? Like I said in the previous post, it has been a while and the scientific size of the organism aside I still didn't see how 11:59 could have been the right answer, even after reading all of the posts. well spotted answer for old wording is 11:59 answer for new wording is 12:44 Link to comment Share on other sites More sharing options...
Guest Posted September 23, 2009 Report Share Posted September 23, 2009 I believe the point of the exercise has been missed: Its a logic puzzle, not a Biology question. The answer is 12:44 (in one more minute) because 1/2(amount of petri dish full) x 2 (the number of cells after each divide) = 1 Link to comment Share on other sites More sharing options...
Guest Posted October 5, 2009 Report Share Posted October 5, 2009 12.44 Link to comment Share on other sites More sharing options...
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