What makes up a molecule in biological terms?

In biological terms, a molecule is defined as two or more atoms that are held together by covalent bonds. This fundamental concept is central to understanding the structure and function of various biological macromolecules, such as proteins, carbohydrates, lipids, and nucleic acids.

When atoms come together and share electrons through covalent bonds, they create stable entities known as molecules. For instance, water (H2O) is a simple molecule comprising two hydrogen atoms covalently bonded to one oxygen atom. Similarly, more complex molecules, such as glucose, consist of multiple atoms bonded together, showcasing the diversity of molecules found in living organisms.

The other options reflect misunderstandings of the molecular concept. While one atom of hydrogen is indeed an atom, it does not constitute a molecule, which requires the combination of multiple atoms. A string of DNA nucleotides is an example of a specific type of molecule but does not encompass the broader definition. Finally, a single organic compound can refer to many different molecules, but by itself does not fully explain the nature of what a molecule is. Therefore, the definition involving multiple atoms bonded together accurately captures the essence of a molecule in biological contexts.