What type of biological molecules do microtubules primarily consist of?

Microtubules are primarily composed of proteins known as tubulin. Tubulin molecules polymerize to form long, cylindrical structures that play a crucial role in various cellular functions, including maintaining cell shape, enabling cellular movement, and facilitating cell division by forming the mitotic spindle. The assembly and disassembly of microtubules allow cells to adapt their structural framework dynamically as needed.

In the context of cellular biology, proteins are the key functional molecules, and their diverse structures and functions are pivotal for life. While nucleotides form the building blocks of nucleic acids (DNA and RNA) and amino acids serve as the building blocks of proteins, they do not directly constitute microtubules. Carbohydrates serve primarily as energy sources or structural components in cells but are not involved in the formation of microtubules. Thus, proteins, specifically tubulin, are the fundamental components of microtubules.