上泽充通大睾 Shanghai Jiao Tong University Growth Factors生长因子 Are organic compounds that are required in very small amounts and only by some cells. Include vitamins,amino acids,purines,and pyrimidines. Shanghai Jiao Tong UniversityShanghai Jiao Tong University Growth Factors 生长因子 • Are organic compounds that are required in very small amounts and only by some cells. • Include vitamins, amino acids, purines, and pyrimidines