NYS DIFFUSION LAB PRACTICE
PART 2: ONION CELL
Base your answers to questions 1 and 2 on the diagram below and on your knowledge of biology. The diagram represents
a cell and its changes as a result of two laboratory procedure. A and B.
1. Describe procedure A and explain why it would cause the change shown.
2. Explain why procedure B has the opposite effect of procedure A.
Base your answers to questions 3 and 4 on the information and data table below and on your knowledge of biology.
In an experiment, three plants of the same species were grown in each of six identical pots. The heights of the
plants were measured when growth began. Each of the pots was watered every day with salt solutions of different
concentrations. The data for the experiment are shown in the table below.
3. State one way diffusion was involved in the cause of death of the plants in groups E and F.
NYS DIFFUSION LAB PRACTICE
4. State the effect of increasing the percent of salt in the solution used to water the plants on the average final height of the
plants in groups A through D.
5. Hospital patients are often given intravenous fluids (IVs) to
maintain proper levels of water and salts in the body. Great care
is used in preparing these solutions. If a manufacturer
accidentally prepared a batch of IV fluid that contained much
more than the usual amount of salt, harm to the could result. The
most likely effect on a patient if this incorrectly prepared IV fluid
was used is that
1) water would move into body cells and cause them to burst
2) water would move out of body cells and cause them to
dehydrate
3) salt and water would both move out of body cells and
disrupt homeostasis
4) salt and water would both move into body cells and preserve
homeostasis
6. A student prepared a wet-mount slide of some red onion cells and
then added some salt water to the slide. The student observed the
slide using a compound light microscope. Diagram A is typical of
what the student observed after adding salt water.
Complete diagram B to show how the contents of the red onion
cells should appear if the cell were then rinsed with distilled
water for several minutes.
NYS DIFFUSION LAB PRACTICE
Base your answers to questions 7 and 8 on the information and data table below and on your knowledge of biology.
A student cut three identical slices from a potato. She determined the mass of each slice. She then
placed them in labeled beakers and added a different solution to each beaker. After 30 minutes, she
removed each potato slice from its solution, removed the excess liquid with a paper towel, and determined
the mass of each slice. The change in mass was calculated and the results are shown in the data table
below.
7. Explain why the potato slice in beaker 1 increased in mass.
8. Identify the process that is responsible for the change in mass of each of the three slices.
Base your answers to questions 9 and 10 on the information below and on your knowledge of biology.
One of the effects of Hurricane Katrina, which devastated New Orleans in 2005, was the death of almost allof the
plants in flooded areas. Initially, toxic chemicals and bacteria were suspected as a possible cause. Scientists later
determined that the salt concentration in the floodwater caused the plants to die.
9. The death of the plants was most likely due to
1)
2)
3)
4)
water moving into plant cells from the surrounding environment
water moving out of plant cells into the surrounding environment
both water and salt moving from plant cells into the surrounding environment
both water and salt moving into plant cells from the surrounding environment
10. Identify the process responsible for the effect that the salt water had on the plants.
11. Some roads are salted heavily in winter. Describe one way plants growing near these roads could be harmed by the salt.
NYS DIFFUSION LAB PRACTICE
12. Base your answer to the following question on the information below and on your knowledge of biology.
A wet-mount slide of red onion cells is studied using a compound light microscope. A drawing of one of the cells
as seen under high power is shown below.
On the diagram below, label the location of each of the cell structures listed.
13. Red onion cells undergo the change represented in the diagram below.
This change is most likely caused by the cell being transferred from
1) distilled water to starch indicator
3) salt water to tap water
2) distilled water to salt water
4) salt water to distilled water
NYS DIFFUSION LAB PRACTICE
Base your answers to questions 14 and 15 on the information and diagram below and on your knowledge of biology.
A wet mount of red onion cells as seen with a compound light microscope is shown below.
14. Which diagram best illustrates the technique that would most likely be used to add salt to these cells?
1)
2)
3)
4)
15. In the space below, sketch what cell A would look like after the addition of the salt.
NYS DIFFUSION LAB PRACTICE
16. The diagram below represents what occurred when an onion cell and a red blood cell were placed in distilled water.
The best explanation for why the onion cells do not burst, while red blood cells often do, is that
1)
2)
3)
4)
the red blood cells have only a cell membrane, which does not protect them from bursting
the onion cells do not have a cell wall that could protect them from bursting
the onion cells have a cell membrane, which can protect them from bursting
the red blood cells have a cell wall, which does not protect them from bursting
Base your answers to questions 17 and 18 on on the information below and on your knowledge of biology.
A student prepared four different red blood cell suspensions, as shown in the chart below.
17. Which suspension would contain red blood cells that would appear wrinkled and reduced in volume?
1) A
2) B
3) C
4) D
18. Which suspension would contain red blood cells that would appear swollen and increased in volume?
1) A
2) B
3) C
4) D
NYS DIFFUSION LAB PRACTICE
Base your answers to questions 19 and 20 on the diagram below, which represents the shrinking of a cell in response to an
increase in the concentration of a substance outside of the cell.
19. Identify one likely substance in the environment of the cell that caused this response.
20. Identify substance A.