Final answer:
Enzymes in anabolic pathways are typically encoded by repressible genes, which are turned off when their end product is plentiful to conserve resources.
Step-by-step explanation:
Enzymes involved in anabolic pathways, which are part of biosynthetic processes where molecules are built up, are typically encoded by repressible genes. These genes can be repressed or 'turned off' when their end product is in abundance, to prevent the unnecessary production of these compounds. This process is known as feedback inhibition, ensuring that cell resources are not wasted. On the contrary, inducible genes are those that are activated in the presence of a specific substrate; for instance, genes encoding enzymes for the degradation of an unusual substrate. In the context of operons, such as the lac operon in E. coli, these inducible genes are turned on only in the presence of lactose to metabolize it efficiently. Constitutive genes refer to those that constantly provide the cell with products, keeping the processes running under normal conditions without the need for inducers or repressors to modulate their expression.