IMAT Membrane transport questions

Sample questions

1. 1IMAT Doutor

   Ouabain blocks the sodium–potassium pump, causing sodium to accumulate inside a cardiac cell. What happens to the intracellular calcium concentration?
   1. AIt rises, because the pump normally brings calcium into the cell together with potassium
   2. BIt rises, because the sodium-calcium exchanger depends on the sodium gradient to expel calcium
   3. CIt falls, because less sodium enters and the calcium channels depend on sodium entry to open
   4. DIt does not change, since calcium transport in the cardiac cell is independent of sodium
   5. EIt falls, because the pump also transports calcium into the sarcoplasmic reticulum
   Show answer

2. 2IMAT 2026 Q16

   What is the primary function of channel proteins in the cell membrane?
   1. ATo catalyse protein synthesis
   2. BTo permit specific substances to pass through the membrane
   3. CTo store energy for active transport
   4. DTo regulate membrane fluidity
   5. ETo transfer DNA out of the cell
   Show answer