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one_raven
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DNA in Chromosomes: Structure unclear
I am a little unclear on the structure of chromosomes and the DNA within, and thought maybe you could point me in the right direction.
It's a little difficult to word this, so I hope it makes sense.
This site and most other sites basically state:
OK, let's say there is a single complete strand of human DNA.
I read that it is about 6 feet long and has something like 3 billion base pairs.
There are 23 pairs of chromosomes in every cell (except reproductive cells).
What I am unclear on is whether each chromosome has a full six-foot strand of 3 billion base pairs, or if each chromosome has its own "section" of the full strand and if you add them all together you get a full strand (or, actually one maternal strand and one paternal strand).
I think each chromosome has it's own "section" of the full strand, but I can't find a definitive answer that says this.
If that is the case, are the chromosomes each their own individual piece as they are illustrated, or is that only done for illustration purposes and it is two long pieces in actuality?
If each chromosome has it's own separate section of the DNA strand, is there any place in the body (or any of our cells) that has a complete unbroken strand of DNA, or does it simply not come that way? Is the six-foot long 3 billion rung "ladder" just a visualization tool, rather DNA is actually 46 separate and distinct DNA molecules never actually being attached to each other?
Any help would be appreciated.
I am a little unclear on the structure of chromosomes and the DNA within, and thought maybe you could point me in the right direction.
It's a little difficult to word this, so I hope it makes sense.
This site and most other sites basically state:
Chromosomes are paired threadlike "packages" of long segments of DNA contained within the nucleus of each cell. In humans there are 23 pairs of chromosomes. In 22 pairs, both members are essentially identical, one deriving from the individual's mother, the other from the father. The 23rd pair is different. In females this pair has two like chromosomes called "X". In males it comprises one "X" and one "Y," two very dissimilar chromosomes. It is these chromosome differences which determine sex.
OK, let's say there is a single complete strand of human DNA.
I read that it is about 6 feet long and has something like 3 billion base pairs.
There are 23 pairs of chromosomes in every cell (except reproductive cells).
What I am unclear on is whether each chromosome has a full six-foot strand of 3 billion base pairs, or if each chromosome has its own "section" of the full strand and if you add them all together you get a full strand (or, actually one maternal strand and one paternal strand).
I think each chromosome has it's own "section" of the full strand, but I can't find a definitive answer that says this.
If that is the case, are the chromosomes each their own individual piece as they are illustrated, or is that only done for illustration purposes and it is two long pieces in actuality?
If each chromosome has it's own separate section of the DNA strand, is there any place in the body (or any of our cells) that has a complete unbroken strand of DNA, or does it simply not come that way? Is the six-foot long 3 billion rung "ladder" just a visualization tool, rather DNA is actually 46 separate and distinct DNA molecules never actually being attached to each other?
Any help would be appreciated.
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