Examples of ligands include which of the following?

Ligands are molecules that bind to specific receptors to initiate a biological response. Examples of ligands include neurotransmitters and hormones, which play crucial roles in cellular communication and regulation within the body. Neurotransmitters transmit signals across synapses in the nervous system, while hormones serve as signaling molecules that travel through the bloodstream to regulate various physiological processes, including metabolism, growth, and mood.

The other options consist of types of molecules that may have biological functions but do not typically act as ligands in the same context. Proteins and lipids can be involved in various cellular processes, but not all of them function as ligands. Carbohydrates and nucleotides are also vital for cellular function, yet they do not primarily serve as ligands in the way neurotransmitters and hormones do. Minerals and vitamins are essential nutrients that support numerous bodily functions but do not act as ligands that bind to specific receptors to elicit a response. Thus, the correct answer highlights the most relevant examples of ligands involved in signaling pathways within the body.