Final answer:
The first step of glycolysis is the phosphorylation of glucose which prevents it from leaking through the plasma membrane, not related to mitochondrial membranes or exclusive to anaerobic organisms.
Step-by-step explanation:
The first step of glycolysis involves the enzyme hexokinase rapidly phosphorylating glucose to form glucose-6-phosphate. Among the options given, the correct answer is that this reaction C. prevents glucose from leaking through the plasma membrane. The phosphorylation adds a negatively charged phosphate group that prevents the phosphorylated molecule from passing through the hydrophobic interior of the plasma membrane. This reaction is not limited to anaerobic organisms, nor does it occur in the mitochondrial membranes.