What are the key structures of a cell found inside its boundaries?

In cellular biology, the structures within a cell that are crucial for its function are the cytoplasm and the nucleus. The cytoplasm is the gel-like substance that fills the interior of the cell and houses various organelles, which are essential for cellular processes. The nucleus, often referred to as the control center of the cell, contains the cell's genetic material (DNA) and is responsible for regulating gene expression and cell division.

The cell membrane, while important as it defines the boundary of the cell and controls what enters and exits, is not located inside the cell itself. Similarly, the plasma membrane is another term often used interchangeably with the cell membrane. Both these terms refer to the lipid bilayer that encloses the cell, but they do not represent structures found within the cell.

In contrast, chloroplasts, ribosomes, cell walls, and cytoskeletons, while vital components in specific cell types or functions, are either organelles found within cells or structures external to the plasma membrane. Chloroplasts are involved in photosynthesis in plant cells, ribosomes are essential for protein synthesis, the cell wall provides structure and protection primarily in plant cells, and the cytoskeleton is crucial for maintaining the cell's shape and aiding in cellular