Vernier Software and Technology
Vernier Software & Technology

Osmosis

Figure from experiment 22 from Biology with Vernier

Introduction

In order to survive, all organisms need to move molecules in and out of their cells. Molecules such as gases (e.g., O2, CO2), water, food, and wastes pass across the cell membrane. There are two ways that the molecules move through the membrane: passive transport and active transport. While active transport requires that the cell uses chemical energy to move substances through the cell membrane, passive transport does not require such energy expenditures. Passive transport occurs spontaneously, using heat energy from the cell's environment.

Diffusion is the movement of molecules by passive transport from a region in which they are highly concentrated to a region in which they are less concentrated. Diffusion continues until the molecules are randomly distributed throughout the system. Osmosis, the movement of water across a membrane, is a special case of diffusion. Water molecules are small and can easily pass through the membrane. Other molecules, such as proteins, DNA, RNA, and sugars are too large to diffuse through the cell membrane. The membrane is said to be semipermeable, since it allows some molecules to diffuse though but not others.

Objectives

In this experiment, you will

  • Use a Gas Pressure Sensor to investigate the relationship between water movement and solute concentration.
  • Determine the water potential of potato cells.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Option 1

Option 2

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Biology with Vernier »

Biology with Vernier

See other experiments from the lab book.

1Energy in Food
2Limitations on Cell Size: Surface Area to Volume
3Acids and Bases
4Diffusion through Membranes
5Conducting Solutions
6AEnzyme Action: Testing Catalase Activity
6BEnzyme Action: Testing Catalase Activity
7Photosynthesis
8The Effect of Alcohol on Biological Membranes
9Biological Membranes
10Transpiration
11ACell Respiration (O2)
11BCell Respiration (CO2)
11CCell Respiration (Pressure)
11DCell Respiration (CO2 and O2)
12ARespiration of Sugars by Yeast
12BSugar Fermentation
13Population Dynamics
14Interdependence of Plants and Animals
15Biodiversity and Ecosystems
16AEffect of Temperature on Respiration
16BEffect of Temperature on Fermentation
17Aerobic Respiration
18Acid Rain
19Dissolved Oxygen in Water
20Watershed Testing
21Physical Profile of a Lake
22Osmosis
23AEffect of Temperature on Cold-Blooded Organisms
23BEffect of Temperature on Cold-Blooded Organisms
24ALactase Action
24BLactase Action
25Primary Productivity
26Control of Human Respiration
27Heart Rate and Physical Fitness
28Monitoring EKG
29Ventilation and Heart Rate
30Oxygen Gas and Human Respiration
31APhotosynthesis and Respiration (O2)
31BPhotosynthesis and Respiration (CO2)
31CPhotosynthesis and Respiration (CO2 and O2)

Experiment 22 from Biology with Vernier Lab Book

<em>Biology with Vernier</em> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

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