Learning should have a route.

Step 1 · Choose the route

Start with the boundary.

Follow a short path through three structures that keep a bacterial cell working.

Step 2 · Learn one idea

The membrane is a selective boundary.

A bacterial cell’s membrane regulates what moves into and out of the cell, helping it maintain the conditions it needs to function.

Step 3 · Recall it

Which structure controls movement into and out of the cell?

Step 4 · See what moved

One concept learned. The route remembers where you are.

Correct—the cell membrane is the selective boundary.