The characteristic size of a virus is about 50 times the helix diameter of a DNA double helix. Selected basis: a representative value for DNA double helix; a representative value for Virus; approximate values.
The ring marks the true-scale position of a DNA double helix; it does not show its width. Only the inset is enlarged (×7.08).
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.
2 nm - Helix diameter; representative.
DNA is the molecule that stores hereditary information in living organisms. Two nucleotide strands wind around one another to form its double helix.
A 2 nm diameter scale for B-form double-stranded DNA. The pictured strand length is illustrative, not the selected measurement.
University of Utah — Cell size and scale100 nm - Characteristic size; representative.
A virus is an infectious particle containing genetic material inside a protein coat, sometimes with an outer envelope. It reproduces only inside host cells.
A chosen 100 nm viral particle, including the approximate envelope. Viruses vary greatly.
University of Utah — Cell size and scale
There’s always another scale
MicroscopicDNA double helix2 nmDNA is the molecule that stores hereditary information in living organisms.
MicroscopicVirus100 nmA virus is an infectious particle containing genetic material inside a protein coat, sometimes with an outer envelope.
Fundamental physicsProton1.682 fmA proton is a positively charged particle found in the nucleus of atoms, made up of quarks.
MicroscopicCell10 µmA cell is the basic structural unit of living organisms.
PeopleHair70 µmA hair is a slender strand of protein that grows from the skin of humans and other mammals.Side by side
Illustrative artwork · not to scale
Illustrative artwork · not to scale
Illustrative artwork · not to scale
Illustrative artwork · not to scaleGot a good eye for scale?