Question involving transport proteins and movement of substance.

[InsaneMcFries]

Part of a question, however information is not required.

c) Transport proteins allow substance X to move through the cell membrane and reduce its concentration in the blood. Name the process by which substance X is removed from the blood and moved into the cell.

I answered Active Transport.

The solution given was Facilitated Diffusion.

As the substance is supposedly moving against the concentration gradient, wouldn't this be called active transport? Or does the involvement of transport proteins mean that it is facilitated diffusion?

[Scooby]

That's a really weird question... the answer could be facilitated diffusion OR active transport, unless it stated whether the cell or the blood contained a greater concentration of Substance X :/

Edit: If it said that the movement is against the concentration gradient, then it's definitely active transport

[Russ]

Was there more information that specifically stated it was moving against a concentration gradient?

The phrasing of the question suggests diffusion, since it states that the proteins "allow substance X to move through" rather than stating that they "move substance X through"

[InsaneMcFries]

Interesting. The original question is as follows.

Through the activity and interaction of the nervous and endocrine systems in humans, homeostasis is maintained. Figure 5 below is a diagrammatic representation, which shows how substance X is maintained at normal levels in the blood by chemicals released from an endocrine gland.

Figure 5 is a flowchart in this sequence.

• Increased concentration of substance X in the blood.
• Organ Z detects increase of substance X.
• Chemical released from organ z.
• Substance X returns to normal levels in the blood.
• Chemical release from organ z stops.

[Flying Emu]

Active transport is very much correct, and so is facilitated transport.

Perhaps it was referencing that organ z releases a hormone which attaches onto receptors allowing substance x to undergo facilitated transport into a cell.

This question is very unclear, but unless is previously in the question [or in the answers of A) or B) ] about a specific substance or referencing ^^^ then active and facilitated transport should be accepted as an answer.

[scar]

Agreed.  Both could easily be correct.  The only way you could argue for Fac Diff is by saying that an increased conc. in the blood gives it the higher conc. than in the cells (assuming that in homeostasis these 2 were in equilibrium).  Movement down the conc. gradient would move X into the cell as a result but not require active transport.  (Ignoring issues about relative conc. size of substance X etc, etc)