The large purple rectangle is a protein channel across a cell membrane. It’s normally closed, but can be opened by binding to a specific small molecule, which is called a ligand. Different channels have different ligands, and their presence/absence controls whether the channels will open.
In the cartoon Larry the ligand has been traveling with his friends, who represent the cargo to be transferred through that channel. When they reach the closed channel, Larry uses himself as the “key” to open the channel. Since channels usually only stay open while the ligand is still bound, Larry stays behind to keep the channel open while his friends make their way forward.
Thank you very much!
I assume that only Larry type molecules were supposed to enter the cell?
No, Larry’s friends are supposed to enter, Larry is there to let them in.
I had the reverse problem, where I’m basically aware of all of the above, but I stared at it for like five straight minutes trying to figure out if there was a deeper joke relating to what the molecules were actually supposed to be, but I think I read too far into it.
