Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Describe how electrons move through the electron transport chain and explain what happens to their energy levels during this process
Explain how a proton (H+) gradient is established and maintained by the electron transport chain

Students practice the initial steps involved in an engineering design challenge. They begin by reviewing the steps of the engineering design loop and discussing the client need for the project. Next, they identify a relevant context, define the problem within their design teams, and examine the project's requirements and constraints. (Note: Conduct this activity in the context of a design project that students are working on, which could be a challenge determined by the teacher, brainstormed with the class, or the example project challenge provided [to design a prosthetic arm that can perform a mechanical function].)

Students extend their knowledge of the skeletal system to biomedical engineering design, specifically the concept of artificial limbs. Students relate the skeleton as a structural system, focusing on the leg as structural necessity. They learn about the design considerations involved in the creation of artificial limbs, including materials and sensors.

Acting as biomedical engineers, students design, build, test and redesign prototype heart valves using materials such as waterproof tape, plastic tubing, flexible plastic and foam sheets, clay, wire and pipe cleaners. They test them with flowing water, representing blood moving through the heart. As students creatively practice engineering problem solving, they demonstrate their understanding of how one-way heart valves work.

Students are introduced to prosthetics history, purpose and benefits, main components, main types, materials, control methods, modern examples including modern materials used to make replacement body parts and the engineering design considerations to develop prostheses. They learn how engineers and medical doctors work together to improve the lives of people with amputations and the challenges faced when designing new prostheses with functional and cosmetic criteria and constraints. A PowerPoint(TM) presentation and two worksheets are provided.

Student teams investigate biomedical engineering and the technology of prosthetics. Students create a model prosthetic lower leg using various materials. Each team demonstrate its prosthesis' strength and consider its pros and cons, giving insight into the characteristics and materials biomedical engineers consider in designing artificial limbs.

This lesson contains background about the blood vascular system and the heart. Also, the different sizes of capillaries, veins, and arteries, and how they affect blood flow through the system. We will then proceed to talk about the heart's function in the blood vascular system. This will lead into a discussion of heart valves, how they work and what might cause them to fail. Then we will discuss prosthetic heart valves.

Students groups act as NASA/GM engineers challenged to design, build and test robotic hands, which are tactile feedback systems made from cloth gloves and force sensor circuits. Student groups construct force sensor circuits using electric components and FlexiForce sensors to which resistance changes based on the applied force. They conduct experiments to find the mathematical relationship between the force applied to the sensor and the output voltages of the circuit. They take several measurements force vs. resistance, force vs. voltage and use the data to find the best fit curve models for the sensor. Different weights applied to the sensor are used as a scalable force. Students use traditional methods and current technology (calculators) to plot the collected data and define the curve equations. Students test their gloves and use a line of best fit to determine the minimum force required to crack an egg held between the index finger and thumb. A PowerPoint(TM) file and many student handouts are included.

This unit focuses on teaching students about the many aspects of biomedical engineering (BME). Students come to see that BME is a broad field that relies on concepts from many engineering disciplines. They also begin to understand some of the special considerations that must be made when dealing with the human body. Activities and class discussions encourage students to think as engineers to come up with their own solutions to some of medical challenges that have been solved throughout the history of BME. Class time iincludes brainstorming and presenting ideas to the class for discussion. Specific activities include examination of the material properties and functions of surgical instruments and prosthetics, a simulation of the training experience of a surgical resident, and an investigation of the properties of fluid flow in vascular tissue.

Students reflect on their experiences making silly putty (the previous hands-on activity in the unit), especially why changing the borax concentration alters the mechanical properties of silly putty and how this pertains to tissue mechanics. Students learn why engineers must understand tissue mechanics in order to design devices that will be implanted or used inside bodies, to study pathologies of tissues and how this alters tissue function, and to design prosthetics. Finally, students learn about collagen, elastin and proteoglycans and their roles in giving body tissues their unique functions. This prepares them for the culminating design-build-test activity of the unit.

Students experience the engineering design process as they design and construct lower-leg prostheses in response to a hypothetical zombie apocalypse scenario. Like the well-known Apollo 13 story during which engineers were challenged to fix the crippled spacecraft with limited supplies in order to save astronauts' lives, in this activity, students act as engineers during an imaginary disaster in which a group member's leg was amputated in order to survive a zombie attack. Building on what they learned and researched in the associated lesson, they design and fabricate a replacement prosthetic limb using given specific starting material and limited additional supplies, similar to how engineers design for individuals while working within constraints. A more-advanced scenario challenges students to design a prosthesis that is able to provide a more-specific movement function.