Question 1

If a person were to hypothetically drink a very large volume of plain tap water, his/her cells would ________.

Accepted Answer

When a person drinks a very large volume of plain tap water, it can lead to a condition known as water intoxication or hyponatremia. This condition dilutes the concentration of electrolytes in the blood, particularly sodium. As a result, water moves into cells by osmosis to balance the concentration gradient, causing the cells to swell. If the swelling is severe, it can lead to cell bursting (lysis).

Question 2

In the molasses experiment, after 30 minutes, the molasses level in the stem of the thistle tube had gone up.

Accepted Answer

The molasses level in the stem of the thistle tube goes up due to capillary action, which is the movement of a liquid through a narrow tube. This movement takes some time, but after 30 minutes, the molasses should have started to rise in the stem of the thistle tube. Therefore, the statement is true.

Question 3

Which of the following transport processes requires the energy of ATP to move substances across the plasma membrane?

Accepted Answer

Active transport requires the energy of ATP to move substances against their concentration gradient across the plasma membrane.

Question 4

When conducting the eggshell membrane experiment, what is vinegar used for?

Accepted Answer

Vinegar is used to remove the eggshell and expose the eggshell membrane, which is the objective of the experiment.

Question 5

In the filtration experiment, which substances passed through the filter paper because of their small molecular size?

Accepted Answer

Water and glucose are small molecules that can pass through the filter paper, while starch and charcoal are too large and get trapped.

Question 6

A 7% solution of glucose would be considered hypertonic to human cells.

Accepted Answer

A 7% solution of glucose would have a higher concentration of solutes than human cells, so it would be considered hypertonic to them. This means that water would flow out of the cells and into the solution, which could cause the cells to shrink and possibly even die.

Question 7

Which of the passive transport processes requires hydrostatic pressure to transport molecules across membranes in the body?

Accepted Answer

Filtration is the only passive transport process that involves the use of hydrostatic pressure. This process occurs in the kidneys where blood is filtered across the capillary walls into the renal tubules.

Question 8

Passive transport processes, such as diffusion, are also called physiological processes.

Accepted Answer

Passive transport processes like diffusion are called physical processes because they involve the movement of substances across membranes without the need for cellular energy, relying instead on the physical principle of moving from areas of higher concentration to areas of lower concentration.

Question 9

An example of filtration in the body is the movement of water and small solutes through the walls of capillaries.

Accepted Answer

This is true. Filtration is a process in which substances are separated based on size or charge by passing through a filter. In the body, filtration occurs in the kidneys, where blood is filtered to remove waste products and excess water. In the capillaries, water and small solutes such as ions and nutrients can pass through the walls of the capillaries through a process called filtration.

Question 10

Which of the following statements is NOT true of diffusion?

Accepted Answer

Diffusion is a passive transport process that occurs due to random molecular motion and moves substances from an area of higher concentration to an area of lower concentration. It is a physical transport process and does not require the energy of ATP. Therefore, statement D is not true.

Question 11

In the carrot experiment to demonstrate osmosis, we would expect the string around the carrot placed in salt water to be tighter than the one placed in tap water, because both the salt and the water diffuse into the carrot.

Accepted Answer

In the carrot experiment, the string around the carrot placed in salt water becomes looser, not tighter, because water diffuses out of the carrot into the salt water (a hypertonic solution) to balance the concentration of solutes, causing the carrot to shrink.

Question 12

In the lab experiment on filtration, iodine potassium iodide (IKI)is used to test for the presence of glucose.

Accepted Answer

Iodine potassium iodide (IKI) is used to test for the presence of starch, not glucose. To test for glucose, Benedict's solution is typically used.

Question 13

Cells placed in a hypotonic solution will shrink.

Accepted Answer

Cells placed in a hypotonic solution will actually swell and potentially burst (lyse) due to the excess water entering the cell.

Question 14

In this lab exercise, potassium permanganate was used to illustrate the process of ________.

Accepted Answer

Potassium permanganate was used in this lab exercise to demonstrate the process of diffusion. Diffusion is the process where particles move from an area of higher concentration to an area of lower concentration until equilibrium is reached.

Question 15

Which of the following is NOT an active process by which substances cross the plasma membrane?

Accepted Answer

Filtration is a passive process where substances move across a membrane due to a pressure gradient. The other options are all active processes that require energy expenditure by the cell.

Quiz 6: Movements Through Membranes