Membrane

Hold a living cell in balance: pump ions uphill against their gradients to fight osmosis, ride out shocks to the bath, and don't run the ATP dry.

How to play

A cell floats in a bath while you watch its ATP, internal and external sodium and potassium, and its volume. Water flows toward higher solute, so if internal solute climbs the cell swells and bursts. You pump ions to hold the volume steady and survive each round's shocks.

• Hold the Pump Na out and Pump K in controls to move ions against their gradients.
• Each pump costs ATP, and the cost scales with how steep the gradient is.
• Keep the cell's volume near its target — swelling leads to lysis, shrinking to collapse.
• Weather the periodic shocks to the bath without bursting or running out of ATP.

Controls

• Desktop: hold the on-screen pump buttons or hold A / left-arrow (Na out) and D / right-arrow (K in); Start and New cell in the bar.
• Phone & tablet: press and hold the two pump buttons — fully touch-friendly.

Tips & strategy

• Pump in short pulses — running a pump flat-out drains ATP faster than the gradient needs.
• Watch volume trend, not just its current value; correct a drift before it accelerates.
• Pumping early against a gentle gradient is cheaper than fighting a steep one later, so don't let imbalances build.

What you'll learn

Membrane turns cellular homeostasis into a real-time survival game built on osmosis and ATP-driven active transport.

• Skills: cell biology, homeostasis, osmosis, active transport
• Best for: roughly grades 9–12 (ages 14+)
• For parents & teachers: cellular homeostasis in real time.

About Membrane

Membrane turns cellular homeostasis into a real-time survival game built on osmosis and ATP-driven active transport. It's an original, free browser game with daily and practice cells to keep alive.

A free, original browser game on PlayPendium — no download, no install. Browse all games →