Which macromolecule serves as a primary source of energy in cells?

Which macromolecule serves as a primary source of energy in cells?

• A. Proteins
• B. Carbohydrates
• C. Nucleic acids
• D. Lipids

Answer: (B)

Carbohydrates serve as the primary source of energy in cells due to their structure and how the body metabolizes them. They are composed of sugar molecules, which can be quickly broken down through various biochemical processes to release energy. Glucose, a simple carbohydrate, is particularly vital because it enters cellular respiration pathways to produce ATP (adenosine triphosphate), the energy currency of the cell. This process allows cells to perform their functions efficiently. In contrast, while proteins, nucleic acids, and lipids can also be used for energy, they are not the primary source. Proteins are more commonly utilized for growth and repair, nucleic acids are involved in genetic information storage and transfer, and lipids serve as secondary energy sources and are crucial for forming cell membranes and other functions. Thus, carbohydrates are distinctively optimized for rapid energy release, positioning them as the foremost energy source in biological systems.

Carbohydrates serve as the primary source of energy in cells due to their structure and how the body metabolizes them. They are composed of sugar molecules, which can be quickly broken down through various biochemical processes to release energy. Glucose, a simple carbohydrate, is particularly vital because it enters cellular respiration pathways to produce ATP (adenosine triphosphate), the energy currency of the cell. This process allows cells to perform their functions efficiently.

In contrast, while proteins, nucleic acids, and lipids can also be used for energy, they are not the primary source. Proteins are more commonly utilized for growth and repair, nucleic acids are involved in genetic information storage and transfer, and lipids serve as secondary energy sources and are crucial for forming cell membranes and other functions. Thus, carbohydrates are distinctively optimized for rapid energy release, positioning them as the foremost energy source in biological systems.