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This case study follows purveyors of peas, Joel E. and Jolene Greengiant, as they learn about the origin, biochemistry, genetics and eventual artificial selection of sweet (wrinkled) peas, all in the context of evolutionary biology. This integrative approach employs both problem-based learning techniques and directed questions as students engage in a series of modules. 

This interrupted case study examines basic concepts of chemical bonding by telling the story of "Madison," a young girl eager to learn how her hair can transition from natural curls to straight, smooth tresses. The case can be used to teach or review the major categories of bonds (ionic, covalent and hydrogen), major macromolecules of life, and hydrolytic and dehydration reactions. It also explores how chemical relaxers and heat through blow drying and flat-ironing can change the nature of straight, wavy and curly hair through the disruption of protein shape. Students will thus learn what it means when a protein has become denatured and how various variables such as pH, heat and salts can lead to the unraveling of the three-dimensional shape of proteins. This case is suitable for an AP high school course, or for an introductory biology or chemistry course for majors or non-majors. This activity can also be used as a review of basic biology and chemistry for students in an upper-level biochemistry course.

Taylor must write a report about a natural toxin while she is home from college on break. After a family dinner conversation about the latest attempt to poison a politician via a letter, Taylor decides to explore how ricin acts as a poison. Students work in small groups to help Taylor by working through figures from primary literature papers and exploring the use of an in vitro translation system, sucrose gradient fractionation and the effect of inhibiting various steps of translation.  A shorter, second day activity involves students looking further at the effect of ricin upon ribosome function and at the ricin protein itself.  Students individually complete a cumulative assignment of writing a letter back to Mom and Dad about how ricin has its effects. This case was designed for use in a second semester biochemistry course or a molecular biology course that incorporates the mechanism of transcription. Prerequisite knowledge includes a general understanding of the steps of translation and the ability to interpret data from agarose gels.

This interrupted case is based on a genome wide association study (GWAS) that identified the genetic variation causing some inhabitants of the Solomon Islands to have blond hair. The case illustrates the connection between genotype and phenotype, and an application of Hardy-Weinberg equilibrium. The narrative focusses on John and his new roommate, Peter, from the Solomon Islands who happens to have dark skin and blond hair. Using thought-provoking questions students learn about the genetics and the biochemistry of the hair color trait and how a single genetic variation can influence phenotype. Is migration or mutation involved?  Upon completion of the activity students will know the source of the genetic variation that causes the blond hair phenomenon in the Solomon Islands and if it has any European origins. The case was written for an upper-level genetics course, but could also be adapted for introductory biology or for a genetics course for non-majors. An optional PowerPoint presentation with clicker questions is available for download from within the Answer Key.

This case study follows a young cystic fibrosis (CF) patient named Lucas. Through Lucas's story and interactions between his parents and pediatrician, students learn about the scientific background and basis of CF. By reviewing email correspondence between Lucas's parents and various doctors, students gain an overview of CF research. CF has become a model disease in certain undergraduate biology classrooms due to its relatively clear mechanism and genetic basis. This case asks students to come up with their own ideas to improve on an existing line of research - gene therapy - in treating CF. During the process, students will gain a better appreciation of the innovative nature of science and develop research skills such as finding, understanding and analyzing primary literature. The activity was originally designed for first- and second-year students as part of an extracurricular case competition, but may be used for any undergraduate biology level. The case assumes basic (high school level) knowledge of genetics, biochemistry, cell biology and physiology.

Before the discovery of insulin in 1921, being diagnosed with Type 1 diabetes was a death sentence. Despite the successful management of diabetes with purified animal insulin, potentially severe side effects were abundant, and alternative ways to produce insulin were needed. This case study guides students through the history of using insulin to treat diabetes, focusing on the development of recombinant DNA technology and the world's first bioengineered drug, recombinant human insulin, which is now used worldwide to treat diabetes. Through the course of this case, students consider the central dogma of molecular biology, the development of recombinant DNA technology, drug design, the importance of recombinant proteins to our society, and the ethical analysis and debates that occur as a result of some scientific discoveries. This case was developed as an introduction to an upper-division biotechnology course focusing on recombinant protein design and production, but could also be used in molecular biology, biochemistry, or introductory biology courses to highlight recombinant DNA and biotechnology.

This case study details the historical discovery of the structure of DNA. Images of this key molecule are as iconic as those of the Mona Lisa, and identifying its structure has proven to be as intriguing a mystery for scientists as the reason behind Mona Lisa's smile has been for art historians. The case is woven together by a series of fictional diary entries that detail the history of the discovery of DNA's structure, the major players involved, their ethical dilemmas, and the role of women in science. The case is designed for a high school course or introductory undergraduate genetics/ biochemistry courses. It can also be used as an interdisciplinary case study bridging genetics, bioethics, art, and the status of women in science. Designed as an interrupted case, it may be used in its entirety or in parts that pertain to a particular topic or discipline. No prior knowledge of genetics is required.

Behind every fart (and poop) is an army of gut bacteria undergoing some crazy (and crazy useful) biochemistry. Learn what they have in common with beer brewing, and why we'd want to know about this science anyway...

Was the "Brooklyn Butcher" of 1926 a cold-blooded killer or was something less sinister at play? This interrupted case study introduces students to hemoglobin binding and carbon monoxide poisoning by working through the details of a fictionalized account of a true-crime story. Topics covered include molecule conformational states, binding affinity, deoxyhemoglobin, oxyhemoglobin, carboxyhemoglobin, and oxygen transport. Students also design an experiment to determine the cause of death of the victim. Prior to beginning the activity students should have some knowledge of the respiratory and circulatory systems and be familiar with oxygen binding curves. Detailed understanding of hemoglobin conformational changes is not necessary since this information is covered in the case. Students will also learn briefly about the electromagnetic spectrum and visible light. Originally developed for a non-majors, pre-nursing anatomy and physiology course, the case is also appropriate for use in any of the following courses: introductory biochemistry, introductory biology, introductory chemistry, nursing, exercise physiology, or possibly even introductory physics.

"This case study introduces students to Duchenne muscular dystrophy (DMD) and its underlying genetics, cell biology, and some of the associated biochemical pathways.  DMD is an X-linked disorder characterized by progressive muscle weakness and wasting due to the absence of a protein called dystrophin, which in turn causes degeneration of skeletal and cardiac muscle. There is currently no established cure for this disease.  The case follows the progress of "Casey," an undergraduate student who has just declared her biology major and is interested in expanding her scientific understanding of the different fields of biology. The case is organized in three parts: genetics, cell biology, and biochemistry, each exploring DMD through its unique lens. Throughout the case, Casey is presented with multiple outlets of information, including class lectures, direct e-mail interaction with a professor, scientific journals and websites, from which she (and any student engaged with the case) gathers knowledge about DMD."

This case study describes a visit by "Naomi" to her physician, who upon seeing Naomi's bloodwork decides to prescribe her a cholesterol-lowering agent, a statin. The case discusses (1) the prevalence of non-communicable diseases such as atherosclerosis, which can lead to strokes and heart disease; (2) circulating lipoprotein particles including LDL and HDL, differentiating between which is a risk factor for heart disease and which is protective;  (3) the pathway for cholesterol synthesis; (4) the evidence demonstrating that statins inhibit the enzyme HMG-CoA reductase, which is the committed step for cholesterol synthesis; and (5) the kinetic mechanism by which statins inhibit the enzyme. Students examine and interpret data from radioactive tracer and enzyme kinetics studies. The case ends with another visit by Naomi to her physician, who reexamines her bloodwork after she has been taking a statin for six months. Students are asked to determine whether the drug was effective for Naomi and, if not, what changes could be made to her regimen. The case was originally written for use in a survey of biochemistry course for upper level undergraduates.

The protagonist of this two-day flipped case study, "Maria," has two problems. She doesn't like it when the apple slices in her lunch turn brown, and she needs to find a project for her biology class that includes molecular biology, preferably one that incorporates plants. Students are enlisted to help Maria understand Arctic Apples™, which don't turn brown because they have been genetically modified to suppress the expression of polyphenol oxidase via RNAi. The case also explores the health, environmental, and safety aspects of growing and eating plants that have been genetically modified to use RNAi. The case applies the central dogma of biology to the creation of genetically modified foods and RNAi and includes a discussion of whether genetically modified foods should be labeled. Several videos are included with the case, including one created by the author specifically for the case. The case is appropriate for use in an introductory level biology or survey level biochemistry course.

Lesson and Units from Science Box

3:47 video: Vinegar may have a powerful smell, but did you know it's actually a weak acid? In the chemical economy, acids actively give away their protons while bases actively collect them -- but some more aggressively than others. George Zaidan and Charles Morton use the currency of subatomic particles to explain this unseen exchange.

5:10 video: extended from Study.com showing lactase example

In order to be useful in treating human infections, antibiotics must selectively target bacteria for eradication and not the cells of its human host. Indeed, modern antibiotics act either on processes that are unique to bacteria--such as the synthesis of cell walls or folic acid--or on bacterium-specific targets within processes that are common to both bacterium and human cells, including protein or DNA replication. Following are some examples.

10 second video showing bacerial killed by penicillin

How do we know what matter is made of? The quest for the atom has been a long one, beginning 2,400 years ago with the work of a Greek philosopher and later continued by a Quaker and a few Nobel Prize-winning scientists. Theresa Doud details the history of atomic theory.

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