Follow one protein from the ribosome that builds it to the place it ends up — and watch it stay wrapped in membrane the entire way.
The nuclear envelope, ER, Golgi, vesicles, lysosomes and plasma membrane are usually taught as a list. They are better understood as a single production line that a protein travels down — enclosed the entire way.
From the moment it is made, an exported protein is inside a membrane. That is what makes shipping digestive enzymes survivable.
Vesicles pinch off one compartment and merge with the next, carrying cargo and membrane in the same movement.
Every protein takes an identical route until the trans Golgi. A chemical label there decides where it ends up.
Tap each part. Notice that two of them are destinations rather than machinery.
Tap the nucleus, rough ER, smooth ER, Golgi, vesicles, lysosome or plasma membrane.
Watch a single protein travel from ribosome to destination. Pick where it ends up, then run it again and pick somewhere else — the first seven steps are identical every time.
It is easy to watch the cargo and forget the container. But the container is going somewhere as well, and it never gets thrown away.
Every fusion donates a patch of membrane to the receiving compartment. ER becomes vesicle, vesicle becomes Golgi, Golgi becomes cell surface.
Endocytosis retrieves membrane from the surface, so a secreting cell does not inflate. Traffic runs in both directions.
The ER lumen is equivalent to the outside of the cell. Two fusions later, whatever faced the lumen faces the world.
Tap a node to light up its connections. The pink dashed link is the principle the whole system exists to protect.
One route, one decision point, three destinations.
Drag a term into a gap, or tap a term and then tap a gap. Two terms belong nowhere.
A protein enters the endomembrane system because a directs its ribosome to the rough ER, where the growing chain is threaded into the . It then leaves enclosed in a , which fuses with the face of the Golgi. Modification such as happens as the cargo advances through the stack, and sorting occurs at the face. A protein tagged with is routed to a lysosome, whereas a secreted protein leaves the cell by .
Single best answer. You get the reasoning as soon as you commit.