Optometry Admission Test (OAT) Practice

Where does glycolysis occur within the cell?

1. Nucleus

2. Mitochondria

3. Cytoplasm

4. Endoplasmic reticulum

The correct answer is: Cytoplasm

Glycolysis is a fundamental metabolic pathway that breaks down glucose to produce energy in the form of ATP. This process occurs in the cytoplasm of the cell. The cytoplasm provides the necessary environment and enzymatic machinery for the glycolytic enzymes to function effectively. Unlike other metabolic pathways, such as the Krebs cycle or oxidative phosphorylation, which occur in the mitochondria, glycolysis is unique in that it does not require specialized organelles to take place. Instead, it utilizes the cytoplasmic space, where the glucose molecules are phosphorylated and subsequently split into two molecules of pyruvate while generating a small amount of ATP and NADH in the process. The other locations mentioned, such as the nucleus, mitochondria, and endoplasmic reticulum, do not support this biochemical pathway. The nucleus is primarily involved in genetic information storage and processing, while the mitochondria focus on aerobic respiration. The endoplasmic reticulum is mainly involved in protein and lipid synthesis processes, making the cytoplasm the sole site for glycolysis to occur.