Human Physiology Quizzes

Go to Quiz 1, 2, 3, 4, 5, 6, 7

Quiz 1

1. In net diffusion, a substance always moves from an area of  HIGH concentration to an area of  LOW concentration.

2. What is the source of energy that drives diffusion (what is the origin of the force that pushes the molecules)?

heat energy

3. A single cell is placed in a 1 liter solution of 0.2 M galactose. If there is initially no galactose in the cell and if galactose is permeable, what will be the concentration of galactose inside the cell when equilibrium is achieved?

0.2 M

4. List three functions of membrane proteins mentioned in class.

channels or pores, carrier proteins, receptors

5. You have created an artificial membrane that has no membrane proteins. Would you expect glucose to be permeable through this membrane. Explain.

No, glucose is hydrophilic and would not be able to go through the hydrophobic core of the lipid bilayer that makes up this membrane.

6. What is meant by the term hydrophilic?

    "water loving", meaning that it is water soluble

7. True/False: Equilibrium is best defined as being the state in which two solutions have the same concentration of solutes.

8. Solution A has a concentration of glucose = 1.0 M while Solution B has a concentration of glucose = 2.0 M. If these two solutions are separated by a barrier that is impermeable to glucose but is permeable to water, where will the water move (net movement)?

Into A

Into B

Neither, the water is in equilibrium

9. A solution contains 1 M glucose, 1 M NaCl and 1 M sucrose. Calculate the osmolarity of the solution.

1 osm (from glucose) + 2 osm (from NaCl) + 1 osm (from sucrose) = 4 osm

10. True/False: Under the correct conditions, it is possible for diffusion to move a substance from an area of high concentration to an area of low concentration.

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Quiz 2

1. Solution A is hyperosmotic to solution B. Will water flow into A or into B or what?

or what!  The term hyperosmotic tells us nothing about permeabilities and therefore not enough info is known to make a determination.  Now, if solution A was hypertonic ...

2. What is meant by the term hypoosmotic?

... a solution with a lower concentration of solutes than another solution

3. True/False: If a substance is in equilibrium across the cell membrane, then the intracellular concentration of the ion must be the same as the extracellular concentration.

4. You are study the endoplamsmic reticulum in skeletal muscle cells. You discover that the calcium concentration inside these organelles is 100 times higher than that measured outside the organelle. What basic mechanism do you think put the calcium into this structure?

A. diffusion
B. osmosis

C. active transport

5. What is the osmolarity of a typical cell?

0.3 osm or 300 mosm

6. Define the term hypotonic?

a solution with a lower concentration of impermeable solutes than another solution

7-8. List the two properties of active transport that differentiate it from diffusion.

- moves substances from low concentration to high concentration
- requires the use of cellular energy

9. What is the term given to diffusion that uses a carrier protein.

facilitated diffusion

10. Titans or Rams

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Quiz 3

1. A positive charged ion will move towards a (negative/positive) charge.

2. According to the laws of physics, like charges will (attract/repel).

3. True/False: If an ion is in equilibrium across the cell membrane, then the intracellular concentration of the ion must be the same as the extracellular concentration.

For the next three questions, assume that a new form of life has been discovered on one of the moons of Jupiter. The intracellular concentration of Cl- in these organisms is much greater than the extracellular concentration of Cl-.

4. Diffusion will move this ion (into/out of) of the cell.

5. If the ion is in equilibrium, the electrical force will move the Cl- (into/out of) of the cell.

6. If the ion is in equilibrium, what would be the charge on the inside of the cell: (positive/negative).

7-8. List the two properties of active transport that differentiate it from diffusion.

moves substances against a concentration gradient
requires cellular energy

9. What is the term given to diffusion that uses a carrier protein.

facilitated diffusion

10. Did they save Private Ryan?

They certainly did

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Quiz 4

1. If the inside of the cell has a positive membrane potential and the extracellular concentration of Cl- is equal the intracellular concentration, could this ion be in equilibrium under these conditions?

YES NO

2. True/False: The Nernst equation is used to calculate the membrane potential of a cell.

3. Assume that the equilibrium potential for sodium is -50 mV and for potassium is +50 mV. If potassium is the only permeable ion, then what is the membrane potential for this cell?

a. -50 mV 
b. + 50 mV
c. 0 mV 
d. cannot determine using the information given

4. Write the Nernst equation (the shortened version is fine):

Equilibrium Potential = (59/z) log (Xo/Xi)

5. If the intracellular concentration of HCO3- is greater than the extracellular concentration, then the equilibrium potential for HCO3- would be (positive, negative, 0).

6. In a normal cell, the sodium concentration in a cell is (greater than/less than/the same as) the extracellular concentration of sodium.

7. If the equilibrium potential for the potassium ion is -89 mV and assuming that potassium is permeable, potassium moves (into/out of) the cell. (Membrane potential = -100 mV)

8. Under the conditions outlined in question 7, what would the membrane potential of the cell be if potassium in equilibrium?

-89 mV

9. True/False: Anytime a protein carrier is involved in the movement of a substance across the plasma membrane of a cell, one can safely assume that the carrier is involved in an active transport mechanism.

10. True/False: Under the appropriate conditions, it is possible for diffusion alone to move a substance from an area of low concentration to an area of high concentration.

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 Quiz 5

1. If the inside of the cell has a positive membrane potential and the extracellular concentration of Na+ is equal the intracellular concentration, could this ion be in equilibrium under these conditions?

YES NO

2. True/False: The Nernst equation is used to calculate the membrane potential of a cell.

3. Assume that the equilibrium potential for sodium is +45 mV and for potassium is -85 mV. If potassium is the only permeable ion, then what is the membrane potential for this cell?

a. -85 mV 
b. + 45 mV
c. 0 mV 
d. cannot determine using the information given

4. Write the Nernst equation (the shortened version is fine):

Equilibrium Potential = (59/z) log (Xo/Xi)

5. What are the two factors about sodium and potassium that one must know to calculate the membrane potential of a cell (according to the equation used to calculate the membrane potential)?

concentration of ions and their permeability

6. In a typical cell, the sodium concentration in a cell is (greater than/less than/the same as) the extracellular concentration of sodium.

7. If the equilibrium potential for the potassium ion is -89 mV and assuming that potassium is permeable, potassium move (into/out of) the cell if the membrane potential is -50 mV.

8. Under the conditions outlined in question 7, what would the membrane potential of the cell be if potassium in equilibrium?

-89 mV

9. True/False: Anytime a protein carrier is involved in the movement of a substance across the plasma membrane of a cell, one can safely assume that the carrier is involved in an active transport mechanism.

 

10. True/False: Under the appropriate conditions, it is possible for diffusion alone to move a substance from an area of low concentration to an area of high concentration.

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Quiz 6

1. In a normal resting neuron, the membrane potential is closer to (-70 mV/0 mV/+50 mV).

2-3. List the 4 properties of action potentials as described in class.

all or none
conducted non-decrementally down the axon
has a threshold
has refractory periods

4. True/False: All potassium channels are identical, (all have the same properties).

5. The rising phase of the action potential is due to the increase in the permeability to what ion?

sodium

6. What is meant by a voltage-gated channel?

a channel that opens/closes in response to changes in the membrane potential of a cell

7. True/False: During an action potential, the concentration of sodium inside the cell increases so that the intracellular concentration is greater than the extracellular concentration.

8. What is meant by the term inactivation with reference to ion channels.

inactivation is when the channel is no longer voltage gated (and is therefore closed)

9. What ion is generally permeable in a resting neuron?

potassium

10. I f the permeability of sodium was much greater than the permeability of potassium in a typical neuron, the membrane potential of the cell would be closer to (-70 mV/0 mV/+50 mV).

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