Cell size is an important variable in the study of cellular growth, metabolism, and the cell cycle. The large size of Amoeba proteus and the ease with which it can be collected and cultured have made it a star in biology education—and it was a model for research on cell biology before the introduction of molecular genetic methods. Measuring the cytoplasmic density of a single amoeba without modern instrumentation seems like a difficult task, but this was done with supreme accuracy in the 1940s. The solution was based on the familiar Cartesian diver that is used to demonstrate Archimedes's principle. It required the fabrication of a tiny diver that would respond to the additional mass of a cell. Experiments using this method allowed investigators to study changes in size and density associated with feeding, starvation, and cell division. This research is an illustration of the ingenuity of cell biologists in the pre-molecular genetic era of their field, which is often overlooked by contemporary scientists. The consideration of the mass, density, and buoyancy of free-living amoebas encourages a new hypothesis about the evolution of testate amoebas.

Over the past decade, the development of three-dimensional mammalian cell organization—called human organoids—from stem cells has provided a framework for future clinical therapies. As human organoid research progresses, we also need to keep in mind the cross-cultural and ethical dimensions of human organoids research. Our review article aims to examine the ethical dimensions of cerebral human organoids and provide an ethical framework guide within human organoids research.

The authors of this article applied the determination of phenolic and flavonoid content in small berries to create a didactic cycle based on student-centered active learning (SCAL) in which students actively participated in the topic while studying and profile-forming as future biology and chemistry teachers. The fundamental part of the proposed didactic cycle is that students solve the following task: Determine the phenolic and flavonoid content in berries (Vaccinium myrtillus L., Vaccinium vitis-idaea L., and Vaccinium corymbosum L.) in your region. The submitted interdisciplinary topic is relevant to everyday life, and it aroused interest and enthusiasm among students. The students had the opportunity to test their theoretical knowledge in practical experimental research, and they attempted to work as researchers.

In an age-appropriate remote learning activity developed by a researcher-teacher team, junior high school students learned about the link between human health and food safety. The students were introduced to basic concepts about the innate immune system and food safety through a learning activity that focused on peanut allergens in food products. The students (a) learned how to distinguish between the concepts of immunity and allergy; (b) learned about cross-contamination and the link between allergies and food safety; (c) learned what antibodies are and how they can be used for science; (d) applied basic knowledge about the immune system and food safety to screen for peanut residues in suspect non-peanut food products using a commercial test kit; and (e) applied basic knowledge about the immune system and food safety to create individual poster presentations on other types of allergies, such as soy or dairy allergies.

A robust understanding of body systems is elusive for many students. For instance, musculoskeletal structures and mechanisms often remain abstract and difficult for students to truly understand, even when teachers provide visual representations and accurate anatomical and physiological information. This article (1) presents a lesson for teaching about the musculoskeletal system by having students develop and build a physical model of an arm and (2) describes how teachers can use this experience to promote a deep understanding of the role of muscles, ligaments, and tendons in movement. This concrete learning experience and resulting arm model establishes a foundation for developing a more robust understanding of anatomical, physiological, and general biological principles. This lesson sequence also embeds questions that overtly draw students' attention to important features of scientific models, which is an important nature of science issue appearing in the Next Generation Science Standards. The instructional sequence has been utilized as the foundation of an entire musculoskeletal unit in an elective anatomy and physiology course for ninth grade students, and it can easily be adapted for use in a middle school life science class or a general high school biology course.

The issue of antibiotic resistance among bacterial pathogens is often misunderstood. Here, we present an activity that debunks misconceptions regarding microorganisms, such as bacterial pathogens, and addresses how antibiotics work. We propose this activity be incorporated into middle or high school classrooms addressing both this real-world issue and elements from the Next Generation Science Standards. Students are encouraged to use hands-on experiences toward hypothesis development and testing to better understand how antibiotic resistance is spread among bacterial pathogens and commensals. Over half of the students who participated in this activity self-reported that they were likely to share the information they learned outside of their classroom, reflecting real-time impacts on science stewardship in students. This activity also presents students with an issue that has clear action items they can undertake to effect positive change.

Pesticides and their associated modes of action serve as real-world examples of chemical toxicity, stimulating student interest and supporting their understanding of nervous system function and cell signaling. An open-source web application called “Neuron-to-Neuron Normal and Toxic Actions” hosts narrated animations of pesticide toxic actions and exists as a resource for instructors of advanced secondary or undergraduate biology courses. This article describes the features of the web application, reports student feedback on the animations, and details a cooperative learning procedure for instructors to use the web application in online learning environments or in-person classroom settings with technology support.

Through experience and surveying undergraduate microbiology curriculum, we found that most schools discuss biofilms in lecture classes but not laboratory courses. Biofilms are a concern for both industry and the medical field and should be studied in student laboratories. To study this at an institution, there would need to be an affordable method to assay them. As a sample specimen, Pseudomonas aeruginosa was used as it proliferates into biofilms when it is starved for nutrients, which can be easily simulated in a laboratory environment. Known assays for studying biofilms are expensive, and most departments do not have the materials. In Trypticase Soy Broth (TSB), P. aeruginosa can also be induced to form a biofilm, but the technique is not seen very often because it has not been sufficiently standardized for undergraduate microbiology education laboratories. To account for the absence of specialized reagents, we incubated bacteria for longer periods of time as a means to diminish nutrients or starve the specimen. Using a two-tailed t-test, we were able to show that glass tubes inoculated with P. aeruginosa in TSB for 48 hours were forming distinct biofilms on the glass surface, which is appropriate for undergraduate microbiology laboratory studies.

Developing students' understanding of cells and the microscopic scale is an important goal of biology education. Cells are the building blocks of multicellular organisms, and most of Earth's biodiversity is found at the microscopic scale. Developing an understanding of the microscopic scale requires that students use their quantitative reasoning skills. Here, resources are presented that help students develop their quantitative reasoning skills and improve their understanding of the small scale of microscopic life. The crosscutting concept, Scale, Proportion, and Quantity, and the science and engineering practice, Using Mathematics and Computational Thinking, are highlighted. The development of students' quantitative reasoning skills in biology is universally recognized as an important outcome of biology education.