A collection of presentations, animations, labs and videos on the topic of diffusion.
Science > General
Creative Commons Attribution 3.0
Interpretation of data leads to development of additional hypotheses, the formulation of generalizations, or explanations of natural phenomena.
Important levels of organization for structure and function include organelles, cells, tissues, organs, organ systems, and whole organisms.
Each cell is covered by a membrane that performs a number of important functions for the cell. These include: separation from its outside environment, controlling which molecules enter and leave the cell, and recognition of chemical signals. The processes of diffusion and active transport are important in the movement of materials in and out of cells.
Many organic and inorganic substances dissolved in cells allow necessary chemical reactions to take place in order to maintain life. Large organic food molecules such as proteins and starches must initially be broken down (digested to amino acids and simple sugars respectively), in order to enter cells. Once nutrients enter a cell, the cell will use them as building blocks in the synthesis of compounds necessary for life.
Follows safety rules in the laboratory
Uses graduated cylinders to measure volume
Follows directions to correctly use and interpret chemical indicators
Identifies the control group and/or controlled variables
Collects, organizes, and analyzes data, using a computer and/or other laboratory equipment
Organizes data through the use of data tables and graphs
Analyzes results from observations/expressed data
Formulates an appropriate conclusion or generalization from the results of an experiment
In this lab students will observe the diffusion of a substance across a semi permeable membrane. Students will be required to accurately and precisely make measurements, record observations, make predictions from observations and data, and analyze data/outcomes.
This is a PowerPoint presentation on the movement of materials through membranes. Headings include: cell membrane, selective permeability, active and passive transport, diffusion, concentration, osmosis, osmotic pressure, facilitated diffusion, isotonic, hypotonic, and hypertonic solutions, endocytosis, pinocytosis, and phagocytosis. Some of the images in here are copyrighted. Their inclusion here should be fair use, but they're not covered under the Creative Commons license. Let's get them replaced with open-licensed images.
This resource is part of the Developing Biology course which contains units on Microscopes; Biochemistry; Cells; Cellular Transport; DNA; Photosynthesis and Respiration; Mitosis and Meiosis; Genetics; and Evolution.
This exercise introduces the dynamic complexes of proteins, carbohydrates, and lipids that comprise cell membranes. You should learn that membranes are fluid, with components that move, change, and perform vital physiological roles as they allow cells to communicate with each other and their environment. We also show that membranes also are important for regulating ion and molecular traffic flow between cells,and that defects in membrane components lead to many significant diseases.
Instructions: The following problems have multiple choice answers. Correct answers are reinforced with a brief explanation. Incorrect answers are linked to tutorials to help solve the problem.
1. Membrane components
2. Lipids and aqueous barriers
3. Hydrophobic forces
5. Membrane transport
6. Membrane proteins
9. Water flow solution
10. Membrane stability
12. Penetrating lipid bilayer
13. Cell junctions
14. Energy requirements for transport
15. Oral rehydration
16. Membrane flow
This resource is part of the Biology Links for One Laptop Per Child course which contains units on Exploring Life; The Cell; Genetics; Mechanisms of Evolution; The Evolutionary History of Biological Diversity; Plant Form and Function; Animal Form and Function; Ecology; and Astrobiology.