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CHROMOSOMES

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CHROMOSOMES

Postby mehdi71000 » Thu Jun 14, 2007 2:58 pm

HI EVERY ONE.
IS THERE ONLY ONE SET OF CHROMESONE IN ONE CELL?
THANKS
Last edited by mehdi71000 on Thu Jun 14, 2007 8:49 pm, edited 1 time in total.
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Postby canalon » Thu Jun 14, 2007 5:37 pm

There are no chromesone in any cells. But depending of the kind of cells you can have from one unique chromosome (bacteria) to tens of pairs of chromosome (human have 23 pairs). You can have look here:
http://en.wikipedia.org/wiki/Chromosome
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Postby mehdi71000 » Thu Jun 14, 2007 6:02 pm

No :? You got me totally wrong. Say humans have 23 chromosomes. So let’s say we opened up a human cell nucleus. Would I find only 1 set of 23 chromosomes or 100 sets of the same chromosome?
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Postby Khaiy » Thu Jun 14, 2007 6:23 pm

I guess I'm a little confused about your question, but a chromosome (as depicted on a karyotype chart) is the individual's genome condensed to make it ready for replication; chromosomes are just specific parts of the DNA. There are 23 of these distinct parts, and two copies of each. No more, no less (with the exception of genetic disorders). Every bit of DNA is accounted for in those 23 pairs, and you can't have more than that because there isn't any more DNA to condense. I hope I answered your question, let me know...
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Postby mehdi71000 » Thu Jun 14, 2007 8:21 pm

Ok I’ll explain more.
if I open a nucleus would I find only the 23 chromosomes. And no more of the same? or thousands of the same 23 chromosomes. I guess what im asking is how many of the 23 are there in the cell
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Postby LilKim » Thu Jun 14, 2007 9:11 pm

There are 2 copies of chromosome 1
(One is maternally derived, the other is paternally derived)

There are 2 copies of chromosome 2
(One is maternally derived, the other is paternally derived)

There are 2 copies of chromosome 3
(One is maternally derived, the other is paternally derived)

There are 2 copies of chromosome 4
(One is maternally derived, the other is paternally derived)

and so on and so forth... all the way to X and Y.

Creating a grand total of 46 chromsomes (2 copes of each chromosome.... where either copy is inherited from your mother or father)
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Postby mehdi71000 » Thu Jun 14, 2007 9:57 pm

Ooh I see thanks fro clearing that up for me. So what would happen if I inject more of the chromosome into the cells nucleus? Would the genes express more? Resulting in more growth and size or maybe change structure? By the way I’m not talking about human’s chromosomes, chromosomes in general.
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Postby david23 » Thu Jun 14, 2007 10:49 pm

a single chromosome carries an enormous amount of genes, an organism will not be well if you add something like that to it. Plasmids are simple and most of the times depending what transcription factors needed, you can get a high expression.
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Postby mehdi71000 » Fri Jun 15, 2007 12:25 am

Thanks guys really appreciated. Great stuff.
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Postby LilKim » Sat Jun 16, 2007 5:37 am

Evolution has selected for the number of chromosomes that a "normal, Healthy" person (organism) has. So gain of chromosomes or loss of chromosomes are detrimental .... (because each chromosome has MANY MANY genes)
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Postby mehdi71000 » Sat Jun 16, 2007 11:53 am

Thanks Lilkim.
I still have many serious doubts about evolution. Maybe its true. but my doubts is based on why all the animals look perfect if they are mutating why we don’t have like a 2 headed bird of some weird spices that is like human but look a bit different like 6 fingers or toes I’m sure people with 6 or 3 fingers can all so survive as good as 5 fingers. I’m also very concerned about the way evolution is used in today’s society. my friend told me once the reason he doesn’t believe in god is we have all evolved from bacteria and the bacteria it self was created from chance of molecules sticking together to form a bacteria and by chance some how they form to recognize light and so on. I how ever told him if you wake up one day in a new planet and see a huge skyscraper or a or a suit jacket would you suggest it has been made by chance or have doubts of a creator for that sky scraper. Even in the evolution book it’s about the origin of spices not the origin of life. My teacher told me once of a law in thermo dynamics (I think). He said if you get a jar of 3 colour beans and lay them separately and neatly on top of each other if you shake them for million years you will never get the same combination same as ink in water. No matter how many times you shake it you will not end up with the drop that is seporated from water. I think perfection surrounds life. If you buy a lotto ticket to win you need to play many times to get the 6 numbers. And there are trillions and trillions of molecules in human body. So I say for a human to evolve there must be countless numbers of imperfect humans much much more than perfect humans. Even in today’s time if we are still evolving. There must me billions and billions of imperfect proteins and enzymes and unfinished genes and I don’t see a device in human body that alters dna so I cant believe my eyes area formed by chance. Sorry I needed to get that of my chest.

Sorry if I have a caused headache but I say life is to be expressed freely. I still like the idea of evolution. I say to evolve is to be alive
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Postby LilKim » Sat Jun 16, 2007 4:39 pm

Yeah, i'm don't exactly wan to get into a evolution conversation ... But scientifically, there is more evidence that evolution is 'real'.. than any other 'theory'.

So, lets look at it in very general terms... The reasoning behind why I say 46 chromosomesis "evolutionarily selected" is simple. Becaurse if you have 45 chromosomes (or less) you're either pretty sick or dead ... if you have 47 chromosomes( or more) you're either pretty sick or dead. Thus, there is a reason why we must have 46 chromosomes ... because it is a "selected" number of chromosomes necessary for viabiliy (in humans).

Remember Darwin's "Survival of the fittest" theory (as a basis for evoulation)? Chromosome number is an EXACT example that lends suppor to his theory. (Because you are most 'fit' if you have 46 chromosomes).

There was something that I was thinking about the other day (although i'm not sure if it's an example of evolution). I heard a news report that stated that more people are wearing glasses nowadays than 50 years ago, and by year (???) it is projected that close to 100% of the human population will need corrective lenses by adulthood.

As non-glasses wearing individual, I was pretty shocked when heard that statement. And then I started thinking about the american indians, that roamed the earth HUNDREDS of years ago. They survived on the land by farming, fishing, and hunting. And as I thought more about this whole vision thing going downhill (as an evolutionary process), I think it's not completely unreasonable to think that the American Indians probably had very-good vision... because being able to see well was essential for survival (ie hunting with spears, bow and arrows) back then ...

However, in modern times, I hunt by going to the grocery store and ordering a steak, and picking up a bag of pre-made salad mix. My hunting requires no physical activity and because my steak isn't running-away and hiding .. hunting for it doesn't require perfect vision because I can get close enough to the sign to read the words "S-T-E-A-K".

So you ask why I think this is an example of evolution? Well, nowadays, we don't need our eyes to be 'that-good', because we can just go down to the 1-hr eyeglass shop and have perfect vision. However, eyeglass shops didn't exist hundreds of years and people from those times relied on their senses (ie vision) to be able to hunt, find safety and to survive. (Could you imagine if a entire tribe of indians had poor vision? They probably wouldn't last very long because they couldn't see their food.)

But, with the advent of cheap eye glasses we can STILL survive even if we have poor vision. (Therefore, people who were not "fit" before... are now "fit" for survival because of eyeglasses!!!!)

... so, yah, i'm not sure if this is an example of evolution? (This is just something that I was thinking about while driving one day)

A more factual example of evoultion is the story of sickle cell anemia (SCA).. SCA is essentially a point mutation in the B-globin chain of hemaglobin that has been evolutionarily selected for. People who are heterozygous at the 'SCA' (having a normal SCA copy on one chromosome, and having a mutated SCA copy on the other chromosome) tend to not get fatally sick, and are resistant to malaria. So, if you lived in an area where malaria infection rates were particularly elevated ... being heterozygous for this mutation would give you a survival advantage over:

1.) People having 2 'normal copies of SCA (Because they are suceptible to malaria infection)

or

2.) People having two mutated copies of SCA = Sickle Cell dises (they're generally REALLY sick, and have acute crises that often result in death)

Thus, having 1 copy of the abnormal SCA is "selected" in areas of the world where malaria is prevalent (ie. certain regions in africa) because these types of individuals are "fit" and evoultionarily selected for... because of malaria

(Read more here: http://en.wikipedia.org/wiki/Sickle-cel ... se#History)

.... so, tell me what you think? I think that these may/may-not be examples of evolution

(and i'm not talking about the kind of evolution that says that humans came from bacteria ... cuz I have NO opinion on that... at all)
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