Cytoplasm

Cytoplasm is a semifluid matrix that fills the interior of the cell. In eukaryotic cells, it spans the region between the plasma membrane and the nuclear envelope and includes all membrane-bound organelles.

In prokaryotic cells, which lack a nucleus, the cytoplasm includes everything inside the plasma membrane. This includes the cytosol, ribosomes, and the DNA in the nucleoid region.

In both cell types, the cytoplasmic space is filled with a gel-like matrix called the cytosol. The cytosol is an aqueous solution that contains many dissolved ions, small molecules like water and oxygen, and macromolecules.

Cytoplasm also contains the cytoskeleton, a network of protein fibers responsible for cell shape, cell movement, and intracellular transport.

In eukaryotic cells, the cytoplasm also includes many membrane-bound organelles suspended in the cytosol.

The cytoplasm is the site of many cellular functions. For example, free ribosomes in the cytoplasm carry out protein synthesis.

The aqueous nature of the cytosol also helps proteins fold by driving hydrophobic amino acid side chains into the protein core.