Microfilaments include:
**Core Concept**
Microfilaments, also known as actin filaments, are one of the three main components of the cytoskeleton in eukaryotic cells. They play a crucial role in cell shape determination, muscle contraction, and intracellular signaling.
**Why the Correct Answer is Right**
Microfilaments are composed of two strands of actin proteins twisted together to form a helix. They are involved in various cellular processes, including muscle contraction, cell migration, and cytokinesis. Actin microfilaments interact with myosin motor proteins to produce muscle contraction and movement. The actin cytoskeleton also provides mechanical support and shape to cells.
**Why Each Wrong Option is Incorrect**
**Option A:** Microtubules are another component of the cytoskeleton, composed of tubulin proteins, and are involved in maintaining cell shape, organizing microtubule-dependent motor proteins, and serving as a railroad track for vesicular transport. They are not a type of microfilament.
**Option B:** Intermediate filaments are a component of the cytoskeleton, composed of various proteins such as keratin, vimentin, and lamin, and provide mechanical support and stability to cells. They are not a type of microfilament.
**Option C:** The Golgi apparatus is a complex organelle involved in protein modification, sorting, and packaging. It is not a component of the cytoskeleton and is not a type of microfilament.
**Clinical Pearl / High-Yield Fact**
The actin cytoskeleton is critical for maintaining cellular shape and function, and its dysregulation has been implicated in various diseases, including cancer, muscular dystrophies, and neurodegenerative disorders.
**Correct Answer:** C.