Kev tsim tshuaj lag luam yuav tsum muaj ntau cov tshuaj tshwj xeeb, cov tshuaj no feem ntau yog tsim los ntawm kev lag luam kws kho mob, tab sis nrog kev sib sib zog nqus ntawm kev sib raug zoo ntawm Kev Ua Haujlwm thiab kev nce qib ntawm cov thev naus laus zis, kev lag luam kws kho mob rau qee yam tshuaj intermediates xa mus rau cov tshuaj lag luam tshuaj. Kws tshuaj intermediates yog cov khoom lag luam tshuaj zoo, kev tsim cov tshuaj intermediates tau dhau los ua kev lag luam tseem ceeb hauv kev lag luam chemical thoob ntiaj teb.
Nruab nrab hauv cov cell biology yog hais txog qhov nruab nrab ntawm kev maj mam tawg ntawm qhov ntxaiv nyob ib ncig ntawm kab nruab nrab ntawm qhov kawg ntawm kev faib tawm ntawm tes, thiab cov ntsiab lus ntawm cytoplasm nyob ib puag ncig ntawm kab nruab nrab muaj qhov muaj ntau zuj zus, txoj cai ntom ntaws hu ua thaj chaw nruab nrab.