Glycolysis occurs in which cellular compartment?

• A. Endoplasmic reticulum
• B. Nucleus
• C. Cytoplasm
• D. Mitochondria

Answer: (C)

Glycolysis occurs in the cytoplasm. It’s the first step of glucose metabolism, where one glucose molecule is converted into two pyruvate molecules through a series of enzyme-catalyzed reactions, yielding net ATP and NADH. The enzymes driving glycolysis are soluble in the cytosol, so no organelle membrane is required. If oxygen is present, pyruvate can enter mitochondria for further oxidation, but glycolysis itself takes place in the cytoplasm. The nucleus houses genetic material, and the endoplasmic reticulum is involved in protein and lipid synthesis, making them separate from the glycolytic site.