Suppose that a cell’s demand for ATP suddenly exceeds its supply of ATP from cellular respiration. What is the most likely immediate cellular response?

• A. The mitochondria will begin to break down DNA for energy.
• B. The cell will stop all metabolic processes to conserve energy.
• C. The cell will immediately switch to photosynthesis to generate ATP.
• D. The rate of glycolysis will increase to produce more ATP.

Answer: (D)

Verified step by step guidance

1. Understand the context: ATP (adenosine triphosphate) is the primary energy currency of the cell. When the demand for ATP exceeds its supply, the cell must respond by increasing ATP production through its metabolic pathways.
2. Recall the process of cellular respiration: Cellular respiration consists of glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation. Glycolysis is the first step and occurs in the cytoplasm, producing ATP quickly without requiring oxygen.
3. Analyze the options: Breaking down DNA for energy is not a viable or efficient process for ATP production. Stopping all metabolic processes would halt ATP production entirely, which is counterproductive. Switching to photosynthesis is not possible for most cells, as photosynthesis occurs only in plants, algae, and some bacteria.
4. Focus on glycolysis: Glycolysis is the most immediate and rapid way to produce ATP when the cell is under energy stress. It breaks down glucose into pyruvate, generating a small amount of ATP directly through substrate-level phosphorylation.
5. Conclude the response: The most likely immediate cellular response to an increased demand for ATP is an increase in the rate of glycolysis, as it can quickly provide additional ATP to meet the cell's energy needs.