Which is the primary molecule broken down for energy in cells during cellular respiration?

• A. Fructose
• B. Sucrose
• C. Glucose
• D. Lactose

Answer: (C)

Verified step by step guidance

1. Understand the process of cellular respiration: Cellular respiration is a series of metabolic processes that convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
2. Identify the primary molecule used in cellular respiration: The main molecule broken down for energy in cells during cellular respiration is glucose. Glucose is a simple sugar and a key energy source for cells.
3. Recognize the role of glucose: Glucose is a monosaccharide, and it is the most common carbohydrate used by cells to produce ATP through cellular respiration.
4. Explore the stages of cellular respiration: Cellular respiration involves three main stages: glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation. Glucose is initially broken down in glycolysis.
5. Connect glucose to energy production: During glycolysis, glucose is converted into pyruvate, which then enters the mitochondria to be further processed in the citric acid cycle and oxidative phosphorylation, ultimately producing ATP.