Dar hujayra mutassil ravandhoi sintezi biologi meguzarand. Bo yorii fermentho az moddahoi soddai khurdmolekula payvastagihoi murakkabi kalonmolekula sintez meshavand: az aminokislotaho safeda, az monosakharidho angishtobhoi murakkab, az asoshoi nitrogeni va qandho nukleotidho, az onho kislotahoi nukleini.
Majmui reaksiyahoi sintezi biologi mubodilai plastiki yo assimilyatsiya nomida meshavad. Ravandhoi muqobili sintez dissimilyatsiya nomida shudaast, ki on majmui reaksiyahoi tajziyashavi (parakhashavi) meboshad. Dar vaqti tajziyai payvastagihoi kalonmolekula energiya khorij meshavad, ki on baroi reaksiyahoi sintezi biologi zarur ast.
Reaksiyahoi sintezi biologi bo khususiyati jinsi va fardi farq mekunand. Strukturai sintezi molekulahoi organiki kalon bo paydarhamii nukleotidho dar KDN, yane genotip muayyan megardad. Ravandhoi mubodila bo muhiti dokhilii
organizm – gomeostaz – dar mutassil tagyiryobii sharoiti hasti tamin meshavad. Ba in ravandho, hamchunin ravandhoi sintez – mubodilai plastiki va reaksiyai tajziya, ki dar natijai onho energiya judo shuda, dar bandhoi makroenergii
ATF zakhira megardad, tobe meboshand. Moddahoi sintezshuda dar jarayoni sabzish baroi bunyodi hujayraho va organoidhoi onho, inchunin, baroi ivaz gardidani molekulahoi sarfgashta yo vayronshuda istifoda meshavand. Tamomi reak siyahoi sintez bo furu burda shudani energiya meguzarand.