Question 1

Two aqueous solutions are separated by a selectively permeable membrane that allows water to pass through but does not allow starch to pass through. Solution A is 10% starch and solution B is 5% starch. What will occur?

Accepted Answer

Water will move from the lower concentration of solute (solution B, 5% starch) to the higher concentration of solute (solution A, 10% starch) to try to equalize the solute concentration on both sides of the membrane, a process known as osmosis.

Question 2

A freshwater protozoan, such as Paramecium, tends to__________ because it lives in a__________ environment.

Accepted Answer

A freshwater protozoan like Paramecium lives in a hypotonic environment, where the concentration of solutes is lower outside the cell than inside. This causes water to move into the cell by osmosis, leading to a gain of water.

Question 3

Osmosis moves water from a region of

Accepted Answer

Osmosis is the process by which water moves across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration. This movement aims to equalize solute concentrations on both sides of the membrane.

Question 4

Active transport requires all of the following EXCEPT

Accepted Answer

Active transport requires a gradient, transport proteins, ATP, and a membrane to move substances against their concentration gradient. Aquaporins are involved in facilitating water movement across cell membranes and are not directly involved in active transport mechanisms.

Question 5

The blood plasma of a man who drinks salt water will become__________ to his red blood cells, whereas the red blood cells will be__________ to the blood plasma.

Accepted Answer

Drinking salt water increases the concentration of salt in the blood plasma, making it hypertonic relative to the red blood cells. Consequently, the red blood cells become hypotonic relative to the now saltier plasma.

Question 6

Glucose is a six-carbon sugar that diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Given this information, which transport mechanism is most probably functioning in the intestinal cells?

Accepted Answer

Facilitated diffusion is the most probable mechanism for glucose transport in this scenario because it allows for the rapid movement of glucose across cell membranes through specific transport proteins, bypassing the slow diffusion through the phospholipid bilayer that would occur with simple diffusion.

Question 7

The gases O₂ and CO₂ enter or leave a plant cell by

Accepted Answer

Oxygen (O2) and carbon dioxide (CO2) move across cell membranes by simple diffusion, as they are small, nonpolar molecules that can easily pass through the lipid bilayer without the need for transport proteins or energy.

Question 8

Two similar-sized animal cells are placed in a 0.5% sucrose solution. Cell A enlarges for a while and then stops; cell B continues to enlarge and finally ruptures. Which of the following must have been TRUE at the beginning of the experiment?

Accepted Answer

The answer of Two similar-sized animal cells are placed in...

Question 9

The secretion of excess water via a contractile vesicle of a Paramecium cell is an example of

Accepted Answer

The answer of The secretion of excess water via a...

Question 10

If red blood cells are taken from the body and placed in a hypertonic solution, what happens to the cells?

Accepted Answer

In a hypertonic solution, the concentration of solutes outside the red blood cells is higher than inside, causing water to move out of the cells and leading them to shrivel up.

Question 11

The cytoplasm of a certain cell, such as a neuron, already has a high concentration of K ⁺ ions. How can K⁺ ions continue to enter the cell?

Accepted Answer

Active transport is the process that can move ions or molecules against their concentration gradient, requiring energy, typically in the form of ATP. This allows K+ ions to continue entering a neuron even when its internal concentration is already high.

Question 12

The diffusion of water molecules across a selectively permeable membrane is called

Accepted Answer

Osmosis specifically refers to the movement of water molecules through a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration to equalize the solute concentrations on both sides of the membrane.

Question 13

The rate of facilitated diffusion of a molecule across a membrane will increase as the concentration gradient of the molecule across the membrane increases to a certain point. Eventually, an increase in the concentration of the molecule will not cause any further increase in facilitated diffusion. Thus, there is a maximal rate of facilitated diffusion. This is because

Accepted Answer

Facilitated diffusion is limited by the number of carrier proteins in the membrane. Once all carriers are occupied, increasing the concentration gradient further does not increase the rate of transport, leading to a maximal rate of facilitated diffusion.

Question 14

Suppose you have two glucose solutions separated by a selectively permeable membrane. If there is a concentration gradient of glucose across the membrane, then the solutions cannot be relative to each other.

Accepted Answer

Isotonic solutions have equal concentrations of solutes, so if there's a concentration gradient of glucose across the membrane, the solutions cannot be isotonic relative to each other.

Question 15

Molecules assisted by carrier proteins may cross a selectively permeable membrane by

Accepted Answer

Facilitated diffusion is the process by which molecules cross a cell membrane with the help of carrier proteins, without the expenditure of cellular energy.

Question 16

The slowest rate of diffusion of dye particles in water will occur at

Accepted Answer

The rate of diffusion decreases as the temperature decreases because the kinetic energy of the particles is lower. Therefore, at 10°C, the dye particles will diffuse the slowest compared to higher temperatures.

Question 17

Imagine that beaker A has a 10% sucrose solution, and beaker B has an 8% sucrose solution. This means that

Accepted Answer

Beaker A is hypertonic relative to beaker B because it has a higher concentration of sucrose (10%) compared to beaker B (8%).

Question 18

More than half a century ago, two cell biologists published details of their research involving isolated membrane vesicles from chloroplasts. Normally, the fluid inside these vesicles is near neutral. In an experiment, these membrane vesicles were soaked in an acidic solution (pH 4) until the inside of the vesicle also became pH 4. Based on the details provided in this scenario, by what mechanism could hydrogen ions have crossed the vesicle membrane, and what do you think happened at the molecular level?

Accepted Answer

Facilitated diffusion allows ions like hydrogen to move across membranes through specific channel proteins without the expenditure of energy, which explains how the hydrogen ions could enter the vesicles to equalize the pH.

Question 19

Imagine an artificial cell made with a selectively permeable membrane that allows water to pass through but does not allow sugar to pass. If the artificial cell contains a 1% sugar solution and then you place the cell in a 2% sugar solution, what happens?

Accepted Answer

Water leaves the cell because the external solution is hypertonic (2% sugar) compared to the internal solution (1% sugar), leading to water moving out to try to balance the concentration gradient.

Question 20

Solutions that cause water to enter cells by osmosis are called

Accepted Answer

Hypotonic solutions have a lower concentration of solutes compared to the inside of the cell, causing water to move into the cell by osmosis to balance the solute concentrations.

Quiz 5: Cell Membrane Structure and Function

Two aqueous solutions are separated by a selectively permeable membrane that allows water to pass through but does not allow starch to pass through. Solution A is 10% starch and solution B is 5% starch. What will occur?

A freshwater protozoan, such as Paramecium, tends to because it lives in a environment.

Osmosis moves water from a region of

Active transport requires all of the following EXCEPT

The blood plasma of a man who drinks salt water will become to his red blood cells, whereas the red blood cells will be to the blood plasma.

The gases O₂ and CO₂ enter or leave a plant cell by

Two similar-sized animal cells are placed in a 0.5% sucrose solution. Cell A enlarges for a while and then stops; cell B continues to enlarge and finally ruptures. Which of the following must have been TRUE at the beginning of the experiment?

The secretion of excess water via a contractile vesicle of a Paramecium cell is an example of

If red blood cells are taken from the body and placed in a hypertonic solution, what happens to the cells?

The cytoplasm of a certain cell, such as a neuron, already has a high concentration of K ⁺ ions. How can K⁺ ions continue to enter the cell?

The diffusion of water molecules across a selectively permeable membrane is called

Suppose you have two glucose solutions separated by a selectively permeable membrane. If there is a concentration gradient of glucose across the membrane, then the solutions cannot be relative to each other.

Molecules assisted by carrier proteins may cross a selectively permeable membrane by

The slowest rate of diffusion of dye particles in water will occur at

Imagine that beaker A has a 10% sucrose solution, and beaker B has an 8% sucrose solution. This means that

Imagine an artificial cell made with a selectively permeable membrane that allows water to pass through but does not allow sugar to pass. If the artificial cell contains a 1% sugar solution and then you place the cell in a 2% sugar solution, what happens?

Solutions that cause water to enter cells by osmosis are called

Quiz 5: Cell Membrane Structure and Function

Two aqueous solutions are separated by a selectively permeable membrane that allows water to pass through but does not allow starch to pass through. Solution A is 10% starch and solution B is 5% starch. What will occur?

A freshwater protozoan, such as Paramecium, tends to__________ because it lives in a__________ environment.

Osmosis moves water from a region of

Active transport requires all of the following EXCEPT

The blood plasma of a man who drinks salt water will become__________ to his red blood cells, whereas the red blood cells will be__________ to the blood plasma.

The gases O2 and CO2 enter or leave a plant cell by

Two similar-sized animal cells are placed in a 0.5% sucrose solution. Cell A enlarges for a while and then stops; cell B continues to enlarge and finally ruptures. Which of the following must have been TRUE at the beginning of the experiment?

The secretion of excess water via a contractile vesicle of a Paramecium cell is an example of

If red blood cells are taken from the body and placed in a hypertonic solution, what happens to the cells?

The cytoplasm of a certain cell, such as a neuron, already has a high concentration of K + ions. How can K+ ions continue to enter the cell?

The diffusion of water molecules across a selectively permeable membrane is called

Suppose you have two glucose solutions separated by a selectively permeable membrane. If there is a concentration gradient of glucose across the membrane, then the solutions cannot be relative to each other.

Molecules assisted by carrier proteins may cross a selectively permeable membrane by

The slowest rate of diffusion of dye particles in water will occur at

Imagine that beaker A has a 10% sucrose solution, and beaker B has an 8% sucrose solution. This means that

Imagine an artificial cell made with a selectively permeable membrane that allows water to pass through but does not allow sugar to pass. If the artificial cell contains a 1% sugar solution and then you place the cell in a 2% sugar solution, what happens?

Solutions that cause water to enter cells by osmosis are called

A freshwater protozoan, such as Paramecium, tends to because it lives in a environment.

The blood plasma of a man who drinks salt water will become to his red blood cells, whereas the red blood cells will be to the blood plasma.

The gases O₂ and CO₂ enter or leave a plant cell by

The cytoplasm of a certain cell, such as a neuron, already has a high concentration of K ⁺ ions. How can K⁺ ions continue to enter the cell?