Question

2. Why do cancer cells utilize glycolysis over respiration? The prevailing theory is that they choose to divert glycolytic intermediates into biosynthetic pathways in order to support cellular proliferation. Briefly describe two of these biosynthetic pathways, including the enzymes and metabolites involved, and any cancer-associated alterations (up-down-regulation).

Answer 1

Following pathways gets altered in the cancer cell. Please follow the number given in the figure

Glycolysis: Cancerous cell uses the intermediates of glycolysis pathway for the synthesis of macromolecules. Glucose-6-phosphate (number 1 of figure) enters in the Pentose phosphate pathway (number 2 of figure) to form ribose 5 phosphate which will be used in the synthesis of nucleic acid. Lactic acid (number 3 of the figure) will be used in the synthesis of glucose in the pathway called gluconeogenesis. Lactic acid produced from the end product of glycolysis 9pyruvic acid) and same will be used for the synthesis of glucose so that more macromolecules will be synthesized from the intermediates of glycolytic pathway.

Pentose phosphate pathway and gluconeogenesis both will be upregulated in the cancer cell.