Sickle Cell Anemia
Harvard Medical School
Brigham & Women’s Hospital
In this case study on sickle cell anemia, students are introduced to some of the key researchers responsible for determining the molecular basis of the disease and learn about the functioning of erythrocytes as well as the notion that changes in the environment can influence the functioning of cells. Students also become familiar with the process of osmosis and how it can influence the sickling of the erythrocytes. Throughout the case, students must address experimental design questions. The case was designed for use in the first semester of an introductory majors biology course.
- Identify pieces of experimental evidence.
- Determine whether one piece of experimental evidence supports another piece.
- Determine the need for "blind" tests.
- Understand the proper use of a control for an experiment.
- Recognize how the side groups of amino acids can influence the overall charge of a protein.
- Recognize the interdependence of the different levels of protein structure.
- Understand the role of the nucleus and plasma membrane in the normal functioning of a cell.
- Recognize that changing the environment in a cell can alter the functioning of the cell.
- Determine the osmolarity and tonicity of different solutions.
- Predict the movement of water when cells are placed into solutions of different tonicity.
- Understand how the process of osmosis can alter the concentration of intracellular molecules.
- Understand that more than one variable may affect the sickling rate of red blood cells.
- Predict possible side-effects of treating a patient with solutions of different tonicity.
KeywordsSickle cell anemia; thalassemia; thalassemic disorders; hemoglobin; red blood cell; amin acid; protein structure; osmosis; osmolarity; osmosis; tonicity; experimental design; Linus Pauling; Vernon Ingram
Topical AreasScientific method, History of science
Educational LevelHigh school, Undergraduate lower division
Type / MethodsInterrupted
Subject HeadingsBiology (General) | Biochemistry | Cell Biology | Molecular Biology | Medicine (General) |
The supplemental materials below may be used with this case study. Many of them are tied to the HHMI short film "The Making of the Fittest: Natural Selection in Humans." This film can be accessed from under the Videos tab above or directly at the following URL: http://www.hhmi.org/biointeractive/making-fittest-natural-selection-humans.Activity: How Do Fibers Form?
Activity: Mendelian Genetics, Probability, Pedigree, and Chi-Square Statistics
Activity: A Lesson on the Nature of Science
Activity: Testing a Hypothesis
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The following video(s) are recommended for use in association with this case study.
- Short Film: The Making of the Fittest: Natural Selection in Humans
A keenly observant young man named Tony Allison, working in East Africa in the 1950s, first noticed the connection and assembled the pieces of the puzzle. His story stands as the first and one of the best understood examples of natural selection, where the selective agent, adaptive mutation, and molecule involved are known - and this is in humans to boot. The protection against malaria by the sickle-cell mutation shows how evolution does not necessarily result in the best solution imaginable but proceeds by whatever means are available. Produced by HHMI BioInteractive. Running time: 14:03 min.
- Film Guide: The Making of the Fittest: Natural Selection in Humans
This guide and quiz support the short film "The Making of the Fittest: Natural Selection in Humans." The "At a Glance Film Guide" provides a short summary of the film, along with key concepts and ties to selected curricula and textbooks. The "In-Depth Film Guide for Teachers" includes a more detailed summary and background information, discussion points, lists of related resources and references, and answers to the accompanying student quiz. The "Quiz" is designed as a summative assessment that probes student understanding of the key concepts addressed in the film. Produced by HHMI BioInteractive.
- Animation: Sickle Cell Anemia
A one-minute animation about sickle cell anemia, a genetic disease that affects hemoglobin. A single nucleotide change in the hemoglobin gene causes an amino acid substitution in the hemoglobin protein from glutamic acid to valine. The resulting proteins stick together to form long fibers and distort the shape of the red blood cells. Produced by HHMI BioInteractive. Running time: 1:00 min.