1) The Na+/K+ pump transports how many of each type of molecule? a. 2 Na+ and 3
ID: 211767 • Letter: 1
Question
1) The Na+/K+ pump transports how many of each type of molecule?
a. 2 Na+ and 3 K+
b. 3 Na+ and 4 K+
c. 2 Na+ and 2 K+
d. 3 Na+ and 2 K+
e. 3 Na+ and 3 K+
2) True or False: Gated channels are able to move molecules either down their electrochemical gradient or against their electrochemical gradient.
True/False
3) Which of the following mechanisms would most likely be used to transport Ca2+ into the smooth endoplasmic reticulum?
a. Symporter
b. Uniporter
c. Passive channel
d. Gated channel
e. Pump
4) Under normal conditions, where would you find the highest concentration of PO4- ions?
a. In the cytoplasm
b. Only in the smooth ER
c. Only in the nucleus
d. It depends on where the H+ are found
e. In the extracellular fluid
5) True or False: Uniporters can show saturation in their transport of molecules at high concentrations.
True/False
6) Which of the following mechanisms require the binding of molecule(s) being transported to a specific site on the protein? Select all answers that apply.
a. Antiporter
b. Uniporter
c. Pump
d. Gated channel
e. Passive channel
7) Which of the following would you find in the axon terminal (terminal bouton)?
a. Chemically gated Ca++ channel
b. Chemically gated K+ channel
c. Voltage gated Ca++ channel
d. Chemically gated Na+ channel
e. Voltage gated K+ channel
8) In the following example which direction would water move across the semipermeable membrane assuming the solute cannot cross the membrane?
-Side A: 10% Glucose
-Side B: 30% Glucose
a) There is no movement of water
b) Water moves to side B
c) Water moves to side A
Explanation / Answer
1) In Na+ K+ pump, at a time 3 sodium ions are exported and 2 potassium ions are imported to maintain physiological functions.
2) False. They are only able to move the ions down their gradient. Because for this, it does not require ATPs. Where as when we need to move ions against gradient, energy is needed. So that follows ATPs mediated active transport. But gated channel only works down the ion gradient.
3) Calcium ions are transported by specialized pump located in SER membrane. It is called SERCA pump.
4) Phosphate is an intracellular anion so its concentration is higher in cytoplasm than in any other places. So the correct option is A
5) F.
They attain Vmax but they do not stop working in high concentration by being saturated. The exchange rate gets higher upto it reaches Vmax.
6) Except channels, all the other options are right. Antiport, uniport and pump system require binding of the ion to the protein whereas the channels do not require that. They simply forms a open path to move the molecules.
7) C. voltage gated Ca2+ channels are seen in axon terminal. As we know that nerve impulses are due to voltage differences. So, the calcium channel present there are driven by voltage.
8) B. water will move from side A to side B . We know that the water flows from the site of lower conc. Of solute to the site with higher conc. Of solute. 30% glucose means 30 unit glucose per 100 unit. Whereas, 10% means 10 unit glucose per 100 unit. Now, 30% - cell has more solute but 10% - cell has morw water than solute. So the water would move from A cell to B cell.
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