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This case study explores the topics of diffusion, osmosis, membrane transport, and the physiological significance of glucose and insulin in the human body. The story begins with a high school athlete, Timmy, who is incredibly efficient at metabolizing carbohydrates for energy; this is where the reader is introduced to normal carbohydrate digestion and metabolism for energy within skeletal muscle cells. As Timmy enters college, he withdraws from sports and physical activity but continues to consume massive amounts of highly soluble carbohydrates, resulting in insulin resistance and ultimately type II diabetes. Throughout the case students are prompted with conceptual questions and interactive figures that require the application and transfer of information they have been introduced to. Originally written for intermediate and advanced physiology courses that cover foundational and complex concepts in science, the case is also appropriate for courses in intermediate biology, nutritional sciences, animal sciences, and exercise sciences.

Article objectives To identify the four new kingdoms that were added to the original Linnaean taxonomy. To describe the three domains of the three-domain system of classification. To explain why the three-domain system may need revision in the future.

This case study provides an overview of the seminal experimental work that led to the discovery of DNA structure and the confirmation of the semi-conservative model of DNA replication. By guiding students through a chronological series of historic experiments and discussing some of the collaborations and controversies involved in the original research, students learn about the history and nature of science in addition to several important biological concepts. A number of recommended videos, including one created by the author, enable instructors to use the "flipped-classroom" mode of instruction according to which students read primary literature and watch videos on their own before group discussions and activities. The case study was developed for use in an introductory undergraduate biology course, and would also be appropriate for use in a high school biology course. Some prior knowledge or instruction may be required, depending on the level and learning objectives of the course.

Scientists and healthcare professionals initially exhibited little concern over the Zika virus even after evidence of human infection was first identified in 1952; Zika appeared to be both rare and unassociated with morbidity or mortality. Around 2015 all of this changed as journalists, scientists, public health officials, and laypeople scrambled to learn about its varied modes of transmission and devastating consequences (e.g., birth defects and autoimmune disorders). Although research continues to rapidly evolve, this case study directs students to reliable scientific sources (e.g., Centers for Disease Control and World Health Organization) that will likely continue to provide the most current information in order to explore questions such as: Where did the virus come from? How does it spread? What can we do to prevent it? Students will also consider the public health challenges and possible solutions associated with emerging infectious diseases. The case was originally written for an upper-level biology or public health course in which students already have some basic background knowledge regarding viruses, vaccines, and infectious disease.

This interdisciplinary case study uses the format of a progressive disclosure to explore certain advances in biotechnology and evaluate them within the framework of societal needs, concerns and pressures.  When faced with a heart valve transplant, a high school student and her mother must decide between multiple approaches, some current and others emergent. Highlighted in this case study are the topics of xenotransplantation, 3D bioprinting and the mature minor rule. The case includes a role-playing, public hearing activity that can be used to explore many aspects at the interface of technology and culture: religious rights, parental rights, public health care policy and safety, animal rights, economic issues of organ marketing, and psychological issues of body image.  This case study was originally designed for first year collegiate classes (introduction to biology, introduction to psychology) but is also applicable to AP high school. The flexible nature of the case also allows for expansion of several aspects for advanced classes across multiple disciplines.

This case study tells the story of a group of ten men, recently released from federal penitentiaries, who are housed in a residential reentry center for the remainder of their sentences. Their stay is intended to bridge the gap between incarceration and return to life in the community. Due to the length of time served, the men are poorly skilled in healthy behaviors and self-reliance in the areas of food and activity. Although a work of fiction, the narrative realistically portrays a variety of challenges that the men face including a chronic health issue, menu planning, tight budgets, hunger, boredom, lack of cooking skills, and life without a local supermarket. Innovation, trial and error, and collaboration result in a story of resilience and health behavior change in a sparsely populated area of Northern Michigan. The case was originally developed for a college-level nutrition course, but could also be used in social work, community health, and health education, nursing, and dietetics classes.

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 interrupted case study for the flipped classroom applies evolutionary genetics research to human health. Students learn about a naturally occurring, but rare, allele of the CCR5 gene, CCR5-Δ32, which provides resistance to HIV. They use data from primary literature sources to predict and interpret worldwide patterns of CCR5-Δ32 frequency distribution. They then discuss how these allele frequency patterns may have been driven by selection imposed by various diseases or by other evolutionary mechanisms. Next, they test published data using Hardy-Weinberg equilibrium to examine if CCR5-Δ32 also provides genetic resistance to West Nile virus. Finally, they complete a jigsaw discussion of Nature News articles that report on how CCR5 research is being used to develop therapies to treat HIV. Originally written for the evolution portion of a yearlong biology series for undergraduate majors, the case is also appropriate for some non-majors biology courses or, with added complexity, upper-level evolution, genetics, or cell biology courses.

In this case study, students will have the opportunity to model the spread of tuberculosis and development of antibiotic resistance in a hypothetical prison environment. After reading a brief handout and viewing a short video, students play a simulation game by first identifying a group of prison inmates represented by index cards. The placement of the cards will influence how drug resistance spreads from one inmate to another. Using a dice roll to mimic random probability of infection and antibiotic misuse, students then track the development of resistance to four specific antibiotics, determined by selection of playing card suit. Opportunity for release or transfer on inmates from one facility to another introduces a further level of complexity, allowing students to study resistance spread. This activity was originally designed for a section of an upper-division biology course about antibiotic resistance, but it would also be appropriate for lower-division undergraduate and high school biology courses discussing antibiotic use.

The following has been excerpted from a very popular Worthington publication which was originally published in 1972 as the Manual of Clinical Enzyme Measurements. While some of the presentation may seem somewhat dated, the basic concepts are still helpful for researchers who must use enzymes but who have little background in enzymology.

It is now well known that non-native species have the potential to be harmful to an ecosystem, but that wasn't always the case, and getting rid of non-native invasive species is usually a difficult task. This brief, interrupted case study tells the story of kudzu's introduction into the United States in the late 1800s. It also examines (and even questions) how we define words like "native" versus "non-native" and "invasive" versus "non-invasive." Students will learn how invasive species impact ecosystems and why some non-native species never become established. They also will address questions related to eradicating non-native invasive species. For example, is it okay to attempt to get rid of a non-native species with another non-native species? As part of the activity, students also will have to decide whether or not kudzu should be considered "native" since it has been in the United States since 1876. Originally designed for a general biology course for majors, the case has also been used in a biology class for non-majors as well as an environmental biology class.

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.

This two-minute video provides brief background on the use of zebrafish as a model in studying animal development, before showing a time-lapse sequence of a fertilized zebrafish egg developing into a larva.  The video includes some annotations that help orient the viewer during the time-lapse sequence.  Teachers might want to mute the narration beginning at 0:42 min to avoid giving students too much information.  This phenomenon could stimulate the following driving questions: How does the zebrafish develop from one cell to the many cells that make up the larva? How do the zebrafish cells divide? How are the developing zebrafish cells similar and different from each other? If all cells in the zebrafish develop from the same original cell, then how do some cells develop differently than others? How are cell division and growth related? 

Squirrels are frequent and beloved residents of college campuses throughout the United States, but oftentimes less welcomed by campus maintenance officials who report squirrels nesting in buildings, interfering with airflow from heating and cooling units, and destroying gutters. In this laboratory case, students act as members of a fictitious "squirrel task force" appointed by their campus administrators to provide recommendations for how to manage their school's squirrel population.  Students work in groups to assess the habitat suitability of their campus for squirrels by identifying and measuring trees that provide seasonal food for squirrels, and by identifying desirable hunting perches for common squirrel predators.  Students conduct squirrel surveys in designated campus zones to calculate the number of squirrels per acre on their campus and compare it with mean squirrel densities reported in forested areas and at a rival institution.  Students then compile and synthesize class data to provide management recommendations for university maintenance officials for either increasing or decreasing campus squirrel populations. Originally developed for an undergraduate wildlife biology course, the case could also be used in a lower-division biology or environmental studies course.

3:05min video coiling and replication

STEM PBL cases for purchase from Wake Forest School of Medicine.  HS topics tagged.

TED-Ed with supporting lesson materials through cpalms.org resource site.  Text links include cell cycle, immune system response to cancer, and Laron's syndrome dwarfism which has low incidences of cancer and diabetes.

9:14 video Have you ever wondered how life first got started on Earth? So do scientists! Though the question has not yet been fully answered, a careful study of Chemical Evolution is beginning to shed light on this mystery. In this film you will learn what Chemical Evolution is, how it works, and how it is different from Biological Evolution.

Scientists have long pondered how exactly life began here on Earth. Now, new research sheds light on Earth's creation, and the findings are not what you'd expect!

Are viruses life forms or not? Scientists have been fighting about it for years, and Anthony has more on the latest wrinkle in this seemingly simple yet age-old debate.