Which biomolecule contains carbon, hydrogen, oxygen, and nitrogen, is the source of energy for tissues, and is made up of 20 amino acids?

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Multiple Choice

Which biomolecule contains carbon, hydrogen, oxygen, and nitrogen, is the source of energy for tissues, and is made up of 20 amino acids?

Proteins fit this description because they are built from amino acids, and there are twenty standard amino acids that make up proteins. Each amino acid contains carbon, hydrogen, oxygen, and nitrogen—the nitrogen comes from the amino group—so proteins are the biomolecule among the options that includes nitrogen. Proteins perform many roles in tissues, from building structural components to acting as enzymes, and they can be used for energy if other fuels are scarce. The other biomolecules don’t match all parts: carbohydrates provide energy but lack nitrogen; nucleic acids contain nitrogen and phosphorus but aren’t made of twenty amino acids; lipids are rich energy stores but do not consist of amino acids and have little to no nitrogen.

Proteins fit this description because they are built from amino acids, and there are twenty standard amino acids that make up proteins. Each amino acid contains carbon, hydrogen, oxygen, and nitrogen—the nitrogen comes from the amino group—so proteins are the biomolecule among the options that includes nitrogen. Proteins perform many roles in tissues, from building structural components to acting as enzymes, and they can be used for energy if other fuels are scarce. The other biomolecules don’t match all parts: carbohydrates provide energy but lack nitrogen; nucleic acids contain nitrogen and phosphorus but aren’t made of twenty amino acids; lipids are rich energy stores but do not consist of amino acids and have little to no nitrogen.

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