DNA length converter
Convert DNA between base pairs, physical length and molecular weight — the three ways a sequence gets measured.
That's 50× as long as a PCR primer, while a plasmid is 5× longer. Stretched out, that would be about 0.00034 mm long.
What it means
How long is that?
Figures are for double-stranded B-DNA: 0.34 nm and about 650 daltons per base pair, and 10.5 base pairs to a turn.
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Three things worth knowing
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1 kb = 340 nm = 650 kDa
A thousand base pairs is a third of a micron long and weighs 650 kilodaltons. These are the two constants every molecular biologist carries.
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Measured from the X-ray pattern
The 0.34 nm rise per base and the 3.4 nm repeat came straight off Franklin’s diffraction photographs, and were the clue that ten bases make one turn.
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Base pairs or bases
Double-stranded DNA is counted in base pairs; single-stranded DNA and RNA in bases. A 100-base single strand weighs roughly half a 100-base-pair double one.
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Background
About DNA measurements
One base pair of the ordinary B form of DNA is 0.34 nm long and weighs about 650 daltons. From those two numbers, a sequence length in base pairs converts straight into a physical length and a molecular weight.
The human genome is 3.1 billion base pairs, just over a meter per copy, and about two meters in every cell, since each cell carries two copies.