What term refers to the material inside a living cell excluding the nucleus?

• A. Nucleus
• B. Cytoplasm
• C. Neuromuscular junction
• D. Schwann cell

Answer: (B)

Cytoplasm is the material inside a living cell excluding the nucleus. It fills the space inside the plasma membrane and contains the cytosol (the fluid) along with the various organelles like mitochondria, endoplasmic reticulum, Golgi apparatus, and ribosomes. The nucleus is a separate, membrane-bound organelle that houses the cell’s genetic material and acts as the control center, so it isn’t part of the cytoplasm. This is why the term described by the question refers to the entire cellular contents outside the nucleus that support metabolism and other cellular activities. The other options point to structures that aren’t the filling of the cell: the nucleus is the genetic control center; a neuromuscular junction is a synapse between nerve and muscle; and a Schwann cell is a glial cell that insulates peripheral nerves.