Which type of molecules serve as recognition molecules in cellular processes?

Glycoproteins are the correct choice because they play a crucial role as recognition molecules in various cellular processes. Glycoproteins consist of proteins that are covalently bonded to carbohydrate chains, which can provide specific binding sites for other molecules. This property allows them to participate in diverse functions such as cell-cell communication, immune response, and facilitating cell adhesion.

For example, glycoproteins are found on the surfaces of cells, where they can act as receptors for signaling molecules or as markers that enable the immune system to distinguish between self and non-self. Their carbohydrate portions can vary widely between different cells and organisms, which enhances their ability to serve as specific recognition sites.

The other options do not serve this specific recognition function in cellular processes. Amino acids are the building blocks of proteins but do not directly mediate recognition. Fatty acids primarily serve structural and energy storage roles rather than recognition. Nucleotides are the building blocks of nucleic acids like DNA and RNA and are involved in genetic coding and energy transfer, but they are not primarily recognition molecules.