The sodium ion looked shocked. It had been going the wrong way, against the current. But the pump didn't care. It cracked another ATP. Heave . Another ion. Heave . Against the flow. Uphill. Spending energy like a miser spends gold.
And then Jamie saw it. Not with eyes, but with imagination. explanation of active transport
And in that instant, the pump changed shape. It yawned open on the outside, scooped up a reluctant sodium ion, and then—with a visible, muscular heave —wrenched it through the membrane and spat it out on the inside. The sodium ion looked shocked
The protein pump reached out, grabbed the ATP, and cracked it open like a glow stick. A flash of light, a shiver of energy. It cracked another ATP
Active transport was a protest.
“Active transport,” she announced, capping her marker with a sharp click . “Who can tell me what it is?”