Question 1

When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move

Accepted Answer

Passive transport involves the movement of molecules from regions of higher concentration (or higher chemical potential energy) to regions of lower concentration (or lower chemical potential energy), following the gradient to achieve equilibrium without the use of cellular energy.

Question 2

When more than one ion species (i.e., Na⁺and K⁺) is present on both sides of the membrane, the chemical driving force acting on Na⁺will include

Accepted Answer

The chemical driving force acting on a specific ion, such as Na+, is determined by the concentration gradient of that ion across the membrane. It does not directly include the effects of other ion species, whether they are positively or negatively charged.

Question 3

As an ion moves passively across a membrane into the cell, the progressive increase in concentration within the cell will

Accepted Answer

The progressive increase in ion concentration within the cell decreases the concentration gradient across the membrane, leading to a decrease in the net flux of ions into the cell by passive diffusion.

Question 4

Which of the following can be used to determine an ion's equilibrium potential?

Accepted Answer

The Nernst equation is used to calculate the equilibrium potential of an ion across a membrane, based on the concentration gradient of the ion across the membrane.

Question 5

If a positively charged ion is more concentrated outside the cell, the electrical forces required to balance the chemical gradient would be directed________ . Thus, the equilibrium potential for this
Ion would be________ charged.

Accepted Answer

The electrical forces required to balance the chemical gradient would be directed outward, so the equilibrium potential for this ion would be positively charged.

Question 6

Based solely upon its electrical charge, the inside of a typical cell will tend to attract extracellular________ to move inward.

Accepted Answer

The inside of a typical cell is negatively charged relative to the outside, which means it will tend to attract positively charged ions, or cations, from the extracellular environment to move inward.

Question 7

The unequal distribution of charge in solutions on either side of a membrane will lead to a________ of charge across the membrane and a ________of counter ions in a region close to the membrane.

Accepted Answer

The unequal distribution of charge leads to a separation of charge across the membrane and a clustering of counter ions near the membrane to balance the charge distribution.

Question 8

Which of the following is NOT a determinant of the magnitude and direction of the equilibrium potential for an ion?

Accepted Answer

The equilibrium potential for an ion is determined by its concentration gradient, charge, chemical driving force, and valence, but not by its lipid solubility. The Nernst equation, which is used to calculate the equilibrium potential, does not include lipid solubility as a factor.

Question 9

Chloride has an equilibrium potential of -90 mV. What direction are the chemical and electrical forces acting on the anion at the resting membrane potential ( -70 mV)?

Accepted Answer

The chemical force is directed into the cell because the equilibrium potential for chloride is more negative than the resting membrane potential. The electrical force is directed out of the cell because the resting membrane potential is more positive than the equilibrium potential for chloride.

Question 10

Molecules tend to move spontaneously_______ their chemical gradient.

Accepted Answer

Molecules tend to move spontaneously down their chemical gradient, from areas of higher concentration to areas of lower concentration, until equilibrium is reached.

Question 11

If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed________ . Thus, the equilibrium potential for this
Ion would be________ charged.

Accepted Answer

EFor a positively charged ion that is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed inward to prevent the ion from diffusing out. This creates a situation where the inside of the cell becomes more negative to balance the outward chemical gradient, leading to a negatively charged equilibrium potential. Additionally, the inward direction of electrical forces supports the idea of attracting the positively charged ions back into the cell, which aligns with choice E, indicating the equilibrium potential would be inwardly directed and the cell would be more positively charged to attract the ions back in, correcting the initial imbalance.

Question 12

Of the gradients listed below, which is the MOST accurate description of the force that ultimately determines the movement of ions across the membrane?

Accepted Answer

The electrochemical gradient is the most accurate description because it encompasses both the chemical (concentration) gradient and the electrical (charge) gradient, which together determine the movement of ions across a membrane.

Question 13

Which of the following is found in greater concentration inside the cell than outside?

Accepted Answer

Potassium (K+) is the major cation found in higher concentrations inside the cell compared to the outside, playing a crucial role in maintaining cell potential and involved in various cellular processes.

Question 14

Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?

Accepted Answer

The membrane potential is the result of the unequal distribution of positive and negative ions across the plasma membrane, creating a voltage difference.

Question 15

Comparing intracellular to extracellular fluid, the intracellular fluid has a ________charge relative to the outside of a cell due to the presence of more________in that solution.

Accepted Answer

The intracellular fluid has a negative charge relative to the outside of a cell due to the presence of more anions (negatively charged ions) in that solution.

Question 16

What is responsible for the unequal distribution of ions across a membrane, thereby causing a charge?

Accepted Answer

The answer of What is responsible for the unequal distribution...

Question 17

The potassium equilibrium potential is -94 mV. What does this mean?

Accepted Answer

The potassium equilibrium potential of -94 mV means that at this membrane potential, the chemical force driving potassium ions out of the cell (due to concentration gradient) is exactly balanced by the electrical force pulling them into the cell (due to the negative charge inside the cell). This results in no net movement of potassium ions across the membrane at this potential.

Question 18

The chemical force for which of the following ions is directed into the cell?

Accepted Answer

The chemical force for both sodium and calcium ions is directed into the cell due to their higher concentration outside the cell compared to inside. This gradient drives their movement into the cell when channels specific to them are open.

Question 19

Which of the following cells would have a greater electrical attraction for sodium ions to enter the cell?

Accepted Answer

The cell with a membrane potential of -90 mV would have a greater electrical attraction for sodium ions to enter because it has the most negative charge relative to the outside, making it more attractive to positively charged sodium ions.

Question 20

If the solutions on either side of the membrane have an unequal distribution of charged ions, with the inside having an excess of anions, then the inside of the cell would have to be

Accepted Answer

If the inside of the cell has an excess of anions (negatively charged ions), it would be more negative relative to the outside of the cell.

Quiz 4: Cell Membrane Transport

When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move

When more than one ion species (i.e., Na⁺and K⁺) is present on both sides of the membrane, the chemical driving force acting on Na⁺will include

As an ion moves passively across a membrane into the cell, the progressive increase in concentration within the cell will

Which of the following can be used to determine an ion's equilibrium potential?

If a positively charged ion is more concentrated outside the cell, the electrical forces required to balance the chemical gradient would be directed . Thus, the equilibrium potential for this Ion would be charged.

Based solely upon its electrical charge, the inside of a typical cell will tend to attract extracellular________ to move inward.

The unequal distribution of charge in solutions on either side of a membrane will lead to a of charge across the membrane and a of counter ions in a region close to the membrane.

Which of the following is NOT a determinant of the magnitude and direction of the equilibrium potential for an ion?

Chloride has an equilibrium potential of -90 mV. What direction are the chemical and electrical forces acting on the anion at the resting membrane potential ( -70 mV) ?

Molecules tend to move spontaneously_______ their chemical gradient.

If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed . Thus, the equilibrium potential for this Ion would be charged.

Of the gradients listed below, which is the MOST accurate description of the force that ultimately determines the movement of ions across the membrane?

Which of the following is found in greater concentration inside the cell than outside?

Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?

Comparing intracellular to extracellular fluid, the intracellular fluid has a charge relative to the outside of a cell due to the presence of morein that solution.

What is responsible for the unequal distribution of ions across a membrane, thereby causing a charge?

The potassium equilibrium potential is -94 mV. What does this mean?

The chemical force for which of the following ions is directed into the cell?

Which of the following cells would have a greater electrical attraction for sodium ions to enter the cell?

If the solutions on either side of the membrane have an unequal distribution of charged ions, with the inside having an excess of anions, then the inside of the cell would have to be

Quiz 4: Cell Membrane Transport

When molecules are passively transported across a membrane, the direction of their movement is dictated by the molecule's tendency to move

When more than one ion species (i.e., Na+ and K+) is present on both sides of the membrane, the chemical driving force acting on Na+ will include

As an ion moves passively across a membrane into the cell, the progressive increase in concentration within the cell will

Which of the following can be used to determine an ion's equilibrium potential?

If a positively charged ion is more concentrated outside the cell, the electrical forces required to balance the chemical gradient would be directed________ . Thus, the equilibrium potential for this Ion would be________ charged.

Based solely upon its electrical charge, the inside of a typical cell will tend to attract extracellular________ to move inward.

The unequal distribution of charge in solutions on either side of a membrane will lead to a________ of charge across the membrane and a ________of counter ions in a region close to the membrane.

Which of the following is NOT a determinant of the magnitude and direction of the equilibrium potential for an ion?

Chloride has an equilibrium potential of -90 mV. What direction are the chemical and electrical forces acting on the anion at the resting membrane potential ( -70 mV) ?

Molecules tend to move spontaneously_______ their chemical gradient.

If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed________ . Thus, the equilibrium potential for this Ion would be________ charged.

Of the gradients listed below, which is the MOST accurate description of the force that ultimately determines the movement of ions across the membrane?

Which of the following is found in greater concentration inside the cell than outside?

Which of the following is a reflection of the unequal distribution of positive and negative ions across the plasma membrane?

Comparing intracellular to extracellular fluid, the intracellular fluid has a ________charge relative to the outside of a cell due to the presence of more________in that solution.

What is responsible for the unequal distribution of ions across a membrane, thereby causing a charge?

The potassium equilibrium potential is -94 mV. What does this mean?

The chemical force for which of the following ions is directed into the cell?

Which of the following cells would have a greater electrical attraction for sodium ions to enter the cell?

If the solutions on either side of the membrane have an unequal distribution of charged ions, with the inside having an excess of anions, then the inside of the cell would have to be

When more than one ion species (i.e., Na⁺and K⁺) is present on both sides of the membrane, the chemical driving force acting on Na⁺will include

If a positively charged ion is more concentrated outside the cell, the electrical forces required to balance the chemical gradient would be directed . Thus, the equilibrium potential for this Ion would be charged.

The unequal distribution of charge in solutions on either side of a membrane will lead to a of charge across the membrane and a of counter ions in a region close to the membrane.

If a positively charged ion is more concentrated inside the cell, the electrical forces required to balance the chemical gradient would be directed . Thus, the equilibrium potential for this Ion would be charged.

Comparing intracellular to extracellular fluid, the intracellular fluid has a charge relative to the outside of a cell due to the presence of morein that solution.