Which fuel source is most readily available to all cells from the bloodstream for immediate energy production?

• A. Glucose
• B. Amino acids
• C. Glycogen
• D. Fatty acids

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the role of the bloodstream in delivering nutrients to cells. The bloodstream transports various molecules, including glucose, amino acids, fatty acids, and other nutrients, to cells for energy production and other functions.
2. Step 2: Recall the primary energy molecule used by cells for immediate energy production. Cells rely on ATP (adenosine triphosphate) for energy, and glucose is the most direct source for ATP production through cellular respiration.
3. Step 3: Compare the listed options in terms of their availability and processing time for energy production. Glucose is readily available in the bloodstream and can be quickly metabolized through glycolysis, whereas amino acids and fatty acids require more complex pathways, and glycogen must first be broken down into glucose.
4. Step 4: Consider the metabolic pathways involved. Glucose enters glycolysis directly, producing pyruvate and ATP. Amino acids and fatty acids require additional steps, such as deamination or beta-oxidation, which are slower processes.
5. Step 5: Conclude that glucose is the most readily available fuel source for immediate energy production because it is directly accessible from the bloodstream and quickly metabolized by cells.