What type of biomolecule is primarily composed of carbon, hydrogen, and oxygen, and serves as a source of energy?

What type of biomolecule is primarily composed of carbon, hydrogen, and oxygen, and serves as a source of energy?

• A. Protein
• B. Carbohydrate
• C. Lipid
• D. Nucleotide

Answer: (B)

The correct answer is carbohydrate. Carbohydrates are organic molecules composed mainly of carbon, hydrogen, and oxygen, typically in a ratio of 1:2:1. They are a vital source of energy for living organisms. When consumed, carbohydrates are broken down into glucose, which cells then use for immediate energy or store for later use. This function as an energy source is one of the defining characteristics of carbohydrates, making them essential for metabolic processes in all living beings. In contrast, proteins consist of amino acids that contain carbon, hydrogen, oxygen, and nitrogen, and their primary role is in structure, function, and regulation of the body's tissues and organs, rather than serving as a primary energy source. Lipids, while they also contain carbon, hydrogen, and oxygen, are primarily used for long-term energy storage, insulation, and cell membrane structure, but are not as readily used for immediate energy compared to carbohydrates. Nucleotides make up nucleic acids (like DNA and RNA), which are involved in the storage and transmission of genetic information and are not a direct source of energy. Therefore, the role of carbohydrates as a key energy source distinctly classifies them in this context.

The correct answer is carbohydrate. Carbohydrates are organic molecules composed mainly of carbon, hydrogen, and oxygen, typically in a ratio of 1:2:1. They are a vital source of energy for living organisms. When consumed, carbohydrates are broken down into glucose, which cells then use for immediate energy or store for later use. This function as an energy source is one of the defining characteristics of carbohydrates, making them essential for metabolic processes in all living beings.

In contrast, proteins consist of amino acids that contain carbon, hydrogen, oxygen, and nitrogen, and their primary role is in structure, function, and regulation of the body's tissues and organs, rather than serving as a primary energy source. Lipids, while they also contain carbon, hydrogen, and oxygen, are primarily used for long-term energy storage, insulation, and cell membrane structure, but are not as readily used for immediate energy compared to carbohydrates. Nucleotides make up nucleic acids (like DNA and RNA), which are involved in the storage and transmission of genetic information and are not a direct source of energy. Therefore, the role of carbohydrates as a key energy source distinctly classifies them in this context.