Cellular Energy Processes: TEAS Practice Question with Answer & Explanation

Understanding Energy Transformation in Cells

The correct answer is Photosynthesis. This fundamental biological process is how plants, algae, and certain bacteria capture light energy from the sun and convert it into chemical energy. This energy is stored in the covalent bonds of organic molecules, specifically glucose (a sugar).

Why Photosynthesis is Correct

Photosynthesis occurs in the chloroplasts of eukaryotic cells. It can be summarized by the following chemical equation: 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂ Notice that light energy is an "input." By the end of the process, that energy is "trapped" within the glucose molecule (C₆H₁₂O₆). This provides the primary energy source for nearly all life on Earth.

Why the Other Options are Incorrect

• Cellular Respiration: This is essentially the opposite of photosynthesis. It is the process by which cells break down glucose to release energy in the form of ATP. While photosynthesis builds high-energy molecules, respiration harvests the energy from them.
• Glycolysis: This is the first step of cellular respiration. It involves the breakdown of one glucose molecule into two pyruvate molecules. It releases a small amount of energy; it does not store solar energy.
• Active Transport: This is a cellular mechanism that uses energy (usually ATP) to move substances across a cell membrane against their concentration gradient. It is a consumer of energy, not a storage process for solar energy.

TEAS Concept: Matter and Energy

The TEAS exam expects you to understand the flow of energy through biological systems. Remember that energy cannot be created or destroyed—only transformed.

1. Light Energy (Sun) is transformed into...
2. Chemical Energy (Glucose via Photosynthesis) which is then transformed into...
3. Usable Energy (ATP via Respiration).

Nursing Student Tip

When you see the word "photo" (meaning light) and "synthesis" (meaning to make), think: "Making food using light." This is the only biological process that brings external energy into the food chain!