Inthispaper,wediscussasimplifiedmodelofmitosisinfrogeggsproposedbyM.T.BorisukandJ.J.Tysonin[1].Byusingrigorousqualitativeanalysis,weprovetheexistenceoftheperiodicsolutionsonalargescaleandpresentthespaceregionoftheperiodicsolutionsandtheparameterregioncorespondingtotheperiodicsolution.Wealsopresentthespaceregionandtheparameterregionwheretherearenoperiodicsolutions.Theresultsareinaccordancewiththenumericalresultsin[1]uptothequalitativeproperty.
