Hairpin

Hairpin loop
An area where single-stranded dna or rna has folded back on itself and nucleotides from the two separate segments have base paired, so that the resulting structure appears as the name describes.

Hairpin
A region of single-stranded DNA or RNA that can form base pairs between complementary sequences. For example the sequence 5'...GACGTGNNNNNCTGCAC...

Hairpin loop A loop of nucleic acid formed by duplex formation within a single strand.

A hairpin loop from a pre-mRNA. Notice the single strand and its nitrogen-rich (blue) bases and oxygen-rich (red) backbone.

c) Interference of hairpins and other structures in DNA with less stable duplexes formed upon the DNA hybridization with comparatively short immobilized oligonucleotides of the microchip.

Also, a primer should not easily anneal with itself or others of its kind, building loops or hairpins in the process. This could hinder the annealing with the template DNA. However, small hairpins are usually unavoidable.

It is bent in a hairpin shape — the hypocotyl arch — as it grows up. The two cotyledons protect the epicotyl structures — the plumule — from mechanical damage.

(after F. G. J. Henle, German pathologist)
The long hairpin turn, with a descending and ascending limb, of the renal tubule in the vertebrate kidney; functions in water and salt reabsorption.
lumen ...

See also: Protein, Enzyme, Trans, Strand, Proteins