What is the approximate length of DNA in a human cell?

I'm getting varying information. Does anyone know. The question is probably worded wrong. But try to include sources. Thanks

3 Answers

  • 1 decade ago
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    If you extract all the DNA from 1 cell and stretch it out, it will measure over 6 ft long. Some ppl say 5 ft, some say as many as 9 or even 12 ft. However, I have read and also teach my students that there is "over 6 feet" of DNA located in each human cell- except mature red blood cells b/c the nucleus is not present.

    (But to actually extract and stretch out all of it is impossible since DNA is extremely fragile and will break. In addition, when you extract DNA- in a research lab; one usually uses a piece of tissue and not just 1 cell, this ensures the presence of DNA.)

    Source(s): I'm a university bio instructor.
  • 5 years ago

    I suspect that they are simply too large to separate on a standard agarose gel. Human chromosomes are massive molecules, ranging from about 50 to 250 million base pairs each. That, along with the proteins that go into keeping the DNA all nicely bound up, makes for a very large molecule that won't migrate far on any gel without exceedingly long runtimes or specialist techniques. Straightforward agarose gel electrophoresis is unlikely to separate them. If the gel is dense enough to make the distances between them significant, the run time will be huge. If it is loose enough to allow the DNA to migrate into the gel any significant distance it is unlikely to have the resolution required. Additionaly, if you just do a crude DNA extraction you will end up with a tangled mess of DNA that won't readily separate. Only during cell division do the chromosomes become the neatly packaged discrete units we are familiar with. During most of the cell's life the DNA is only loosely wound, and you certainly cant visually separate the chromosomes. Just to complicate matters further, when they do condense they are long, thin molecules, and these usually migrate differently. Gell electrophoresis is based on the idea that the molecules being separated are roughly spherical, or at least that their orientation doesn't matter. Chromosomes are very long molecules, and that tends to affect their migration too.

  • 1 decade ago

    About 3 meters.

    Plus I'm taking college biology right now. I have a final on Wed. :(

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