Feedback for Multiple Choice Quiz 23
- Carbohydrates are found on the surfaces of membranes. Cholesterol and phospholipds span only half the thickness of the bilayer.
- Only the membrane-spanning, integral proteins function directly in active transport, e.g. by forming pores or channels.
- Nucleic acids are "associated with" or "attached to" membranes, but are not found "in membranes".
- By definition, active transport involves the movement of ions or molecules against a concentration gradient, i.e. in a specific direction relative to the membrane doing the transporting.
- This is really minutiae, but the list at the bottom of the the Lecture 23 notes looked like a natural multiple choice question! The important point is that a variety of lipids are used to anchor proteins in the membrane.
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