Which atom plays a central role in cellular respiration by accepting electrons at the end of the electron transport chain, thereby helping to provide energy for your heart to beat?

• A. Oxygen (O)
• B. Nitrogen (N)
• C. Sodium (Na)
• D. Calcium (Ca)

Answer: (A)

Verified step by step guidance

1. Understand the process of cellular respiration: Cellular respiration is the process by which cells generate energy in the form of ATP. It involves glycolysis, the citric acid cycle, and the electron transport chain.
2. Focus on the electron transport chain: In this stage, electrons are transferred through a series of protein complexes embedded in the inner mitochondrial membrane, creating a proton gradient that drives ATP synthesis.
3. Identify the role of the final electron acceptor: At the end of the electron transport chain, electrons must be accepted by a molecule to prevent the chain from halting. This molecule plays a critical role in maintaining the flow of electrons.
4. Recall the chemical properties of oxygen: Oxygen (O) is highly electronegative, meaning it has a strong ability to attract electrons. This makes it an ideal final electron acceptor in cellular respiration.
5. Conclude that oxygen is the correct answer: Oxygen accepts electrons at the end of the electron transport chain, combining with protons to form water (H₂O). This process is essential for energy production in cells, including those in the heart.