Biennial.
(L. biennium, a period of two years) In botany, a plant which completes its life cycle within two years and then dies. For most biennial plants, the two growing seasons have to be separated by a period of cold temperature sufficient to induce flowering and fruit formation.

Bifunctional Monomer
A monomer unit that has two active bonding positions.

Bifunctional vector
See shuttle vector.

Binding site
A place on cellular DNA to which a protein (such as a transcription factor) can bind. Typically, binding sites might be found in the vicinity of genes, and would be involved in activating transcription of that gene (promoter elements), in enhancing the transcription of that gene (enhancer elements), or in reducing the transcription of that gene (silencers).

NOTE that whether the protein in fact performs these functions may depend on some condition, such as the presence  of a hormone, or the tissue in which the gene is being sites could also be involved in the regulation  of chromosome structure or of DNA replication
Binomial nomenclature
In biology, each species is generally identified by two terms: the first is the genus to which it belongs, and the second is the specific epithet that distinguishes it from others in that genus (e.g., Quercus suber, cork oak). The genus name always has an initial capital; the specific epithet is never capitalized, even though it may be derived from a r per name (e.g., keranda nut, Elaeocarpus bancroftii). Both terms in the binomial are italicized. Based on the system of classification developed by Carolus Linnaeus.

Binomial expansion
The probability that an event will occur 0, 1, 2,.....n times out of n is given by the successive terms of the expression (p + q)n, where p is the probability of the event occurring, and q = 1 - p.

Bio-­
A prefix derived from bios and used in scientific words to associate the concept of "living organisms“. Usually written with a hyphen before vowels, for emphasis in neologisms; otherwise usually without a hyphen.