Which chemotherapy agents are designed structurally to mimic normal cellular metabolites?

Antimetabolites are specifically designed to mimic normal cellular metabolites. These agents interfere with cellular metabolism and function by masquerading as the building blocks or end products required for DNA and RNA synthesis. For example, antimetabolites can resemble nucleotides or other essential molecules, effectively inhibiting the enzymes that participate in nucleic acid production and disrupting the proliferation of cells, particularly those that are rapidly dividing, such as cancer cells.

This mimicry allows antimetabolites to selectively target cancer cells while having a less pronounced effect on normal, non-dividing cells, thereby exploiting the difference in metabolic activity between malignant and healthy tissues. Their effectiveness in inhibiting cancer cell growth is a direct result of their structural similarity to these essential metabolites.

Other options, such as cell cycle specific agents, cytotoxic agents, and hormonal agents, work through different mechanisms that do not rely on the structural mimicry of cellular metabolites, which is why they do not fit the criteria presented in the question.