This infographic was created to visually explain how small genetic differences in the ABO gene lead to distinct blood types through the modification of cell-surface sugars. The work incorporates information from cell biology, genetics, and biochemistry to show how the A and B alleles produce functional enzymes that alter the H antigen in different ways, while the O allele results in no modification. By illustrating the roles of the nucleus, mRNA, protein synthesis, and the Golgi apparatus, the infographic highlights the full cellular pathway from gene to functional antigen. We collected various information from multiple resources and research available to us to construct this infographic to the best of our abilities, making it resourceful for others as well. The infographic’s main goal while being created was making complex molecular processes accessible to students and readers, emphasizing how genotype directly shapes phenotype in one of the most familiar genetic systems studied in biology.