What is the reason carbon atoms are the most versatile building blocks of the molecules used by living organisms?

• A. Carbon is the central atom of carbon dioxide, a necessary molecule for photosynthesis.
• B. Carbon is the central atom in urea, a molecule used by many living organisms to transport wastes from the body.
• C. All of the listed responses are correct.
• D. Each carbon atom acts as an intersection point from which a molecule can branch off in up to four directions.

Answer: (D)

Verified step by step guidance

1. Understand the unique properties of carbon atoms: Carbon has an atomic number of 6, which means it has 4 electrons in its outer shell. This allows carbon to form four covalent bonds with other atoms, making it highly versatile in forming complex molecules.
2. Recognize the significance of carbon's bonding capability: The ability to form four covalent bonds allows carbon to act as an intersection point, enabling the formation of long chains, branched molecules, and rings. This versatility is crucial for the diversity of organic molecules.
3. Consider the role of carbon in biological molecules: Carbon's ability to form stable bonds with many elements, including hydrogen, oxygen, nitrogen, and other carbon atoms, is fundamental to the structure of biomolecules like carbohydrates, proteins, lipids, and nucleic acids.
4. Evaluate the importance of carbon in metabolic processes: Carbon is a key component in metabolic pathways, such as the Calvin cycle in photosynthesis and the citric acid cycle in cellular respiration, highlighting its central role in energy transformation and storage.
5. Reflect on the implications of carbon's versatility: The diverse structures that carbon can form are essential for the complexity and functionality of living organisms, allowing for the vast array of biological molecules necessary for life processes.