ðə kɹˈɪɾɪkəl kˌɑːnsəntɹˈeɪʃən ɪz ðə kˌɑːnsəntɹˈeɪʃən ʌv ˈiːðɚ dʒˈiːˈæktɪn ˈæktɪn ɔːɹ ðɪ ˈælfə,bˈeɪɾə tˈuːbjʊlˌɪn kˈɑːmplɛks mˌaɪkɹoʊtˈuːbjuːlz æt wˌɪtʃ ðɪ ˈɛnd wɪl ɹᵻmˈeɪn ɪn ɐn ˌiːkwɪlˈɪbɹiəm stˈeɪt wɪð nˈoʊ nˈɛt ɡɹˈoʊθ ɔːɹ ʃɹˈɪŋkɪdʒ.
The critical concentration is the concentration of either G-actin (actin) or the alpha,beta- tubulin complex (microtubules) at which the end will remain in an equilibrium state with no net growth or shrinkage.