Which one of the following molecules is a source of energy in the energy-consuming phase of glycolysis?

• A. NADH
• B. FADH₂
• C. ATP
• D. Acetyl CoA

Answer: (C)

Verified step by step guidance

1. Understand the context of glycolysis: Glycolysis is a metabolic pathway that converts glucose into pyruvate, releasing energy and producing ATP and NADH in the process.
2. Identify the energy-consuming phase: Glycolysis consists of two phases - the energy investment phase and the energy payoff phase. The energy-consuming phase is the energy investment phase.
3. Recognize the role of ATP: During the energy investment phase of glycolysis, ATP is used to phosphorylate glucose and its intermediates, which is necessary to drive the reactions forward.
4. Differentiate between the molecules: NADH and FADH2 are electron carriers used in other metabolic processes, while Acetyl CoA is involved in the citric acid cycle, not directly in glycolysis.
5. Conclude that ATP is the molecule used as a source of energy in the energy-consuming phase of glycolysis, as it provides the necessary energy to phosphorylate glucose and its intermediates.