Cytoplasm

Everything inside the cell membrane except the nucleus — the crowded internal environment where most cellular activity happens.

Components

• Cytosol — the gel-like, water-based fluid that fills the cell.
• Organelles — the specialized structures suspended within it (covered separately).
• Inclusions — temporary stores such as glycogen granules and fat droplets.

What it does

• Hosts reactions — many chemical processes, including the first stage of extracting energy from glucose, occur free in the cytosol.
• Holds the machinery — suspends and positions the organelles.
• Transport medium — substances diffuse and are carried through it.

Key idea

The cytoplasm is the cell’s working space — not empty filler but a densely packed, highly organized environment.