Which of the following factors regulate the rate of glycolysis?

• A. The amount of oxygen available
• B. The presence of ribosomes
• C. The pH of the mitochondrial matrix
• D. The concentration of ATP in the cell

Answer: (D)

Verified step by step guidance

1. Understand the process of glycolysis: Glycolysis is the metabolic pathway that breaks down glucose into pyruvate, producing ATP and NADH. It occurs in the cytoplasm and does not require oxygen.
2. Identify the regulatory factors of glycolysis: Glycolysis is regulated by feedback mechanisms, primarily through the concentration of ATP and other molecules like ADP, AMP, and citrate. High ATP levels inhibit glycolysis, while low ATP levels stimulate it.
3. Eliminate irrelevant options: Oxygen availability does not directly regulate glycolysis because glycolysis is anaerobic. Ribosomes are involved in protein synthesis, not glycolysis. The pH of the mitochondrial matrix is related to oxidative phosphorylation, not glycolysis.
4. Focus on ATP concentration: ATP acts as an allosteric inhibitor for key enzymes in glycolysis, such as phosphofructokinase-1 (PFK-1). When ATP levels are high, PFK-1 activity decreases, slowing glycolysis. Conversely, when ATP levels are low, PFK-1 activity increases, accelerating glycolysis.
5. Conclude the correct regulatory factor: Based on the above analysis, the concentration of ATP in the cell is the primary factor regulating the rate of glycolysis.