noun-modifying (irregular)
monobasic; monatomic; single-nucleotide
Chemistry term used prenominally to describe an acid with one replaceable hydrogen atom, a monatomic molecule, or a single-nucleotide unit.
一塩基酸は水溶液中で一つのプロトンを放出する。
A monobasic acid releases one proton in aqueous solution.
一塩基変異は遺伝子の一つのヌクレオチドが置き換わることだ。
A single-nucleotide variant is when one nucleotide in a gene is replaced.
多塩基 means polybasic, having multiple replaceable hydrogen atoms, whereas 一塩基 is specifically monobasic.
Compound of 一 (one) and 塩基 (base), a calque from Western chemistry terminology.