Now, we know that we have many different types of cells and many different types of tissues. And what that means means is these different types of cells, even though they carry out the same type of process for instant glycolysis, the requirements for those biochemical processes in the different types of cells actually might be different. And so what that means is our cells must also be able to closely regulate these biochemical processes and fine tune those regulatory pathways to actually meet the needs and demands of those specific types of cells. And one way by which our body is able to actually regulate and fine tune these specific biochemical processes in the different types of cells in our body is by using molecules known as isozymes or Isa enzymes. And we actually discussed many examples of isozymes previously. For instance, when we discussed the regulatory pathway of glycolysis in skeletal muscle cells and liver cells, we said that pyruvate kinase, the enzyme that catalyzes the final step in glycolysis that we find in skeleton muscle cells and in liver cells, actually come in different forms.