Toronto Metropolitan University

BLG 311

1. Channels are a broad group of membrane proteins. Which of the following are examples of channel
proteins?
(A) P-type ATPases
(B) ABC transporters
(C) V-type ATPase
(D) all of the above
(E) none of the above
2. You are reading a scientific article about a new membrane transport protein called YLG2 that is a
serine/Ca2+ symporter. Serine is an amino acid that represents a nutrient for cells, and serine can be
transported against its concentration gradient by YLG2. Which of the following about the direction of
transport is TRUE, given the typical Ca2+ gradients found across the plasma membrane of a cell?
(A) Serine will be effectively removed from the cell (active transport), as Ca2+ enters the cell by
passive transport.
(B) Serine will be effectively taken up into the cell (active transport), as Ca2+ enters the cell by
passive transport.
(C) Serine will be effectively removed from the cell (active transport), as Ca2+ exits the cell by
passive transport.
(D) Serine will be effectively taken up into the cell (active transport), as Ca2+ exits the cell by
passive transport.
(E) Toronto FC will win a game every time a Ca2+ ion leaks into the cell.
3. Which of the following contribute to establishing a negative membrane potential in most cells at rest?
(A) NHE1
(B) Aquaporin
(C) K+ leak channels
(D) Na+/glucose symporters
(E) none of the above
4. In the context of an action potential, the opening of voltage-gated potassium channels is important for:
(A) establishing the initial, resting membrane potential
(B) membrane re-polarization
(C) membrane depolarization
(D) turning off (closing and/or inactivating) the voltage-gated Na+ channels
(E) keeping the concentration of Ca2+ inside neurons high