The Biology I Course was developed through the Ohio Department of Higher Education OER Innovation Grant. The course is part of the Ohio Transfer Assurance Guides and is also named OSC003. This work was completed and the course was posted in October 2019. For more information about credit transfer between Ohio colleges and universities, please visit: www.ohiohighered.org/transfer.Team LeadCathy Sistilli                                         Eastern Gateway Community CollegeContent ContributorsLisa Aschemeier                                 Northwest State Community CollegeShaun Blevins                                     Rhodes State CollegeRachel Detraz                                     Edison State Community College                                     Sara Finch                                          Sinclair Community CollegeWendy Gagliano                                 Clark State Community College AJ Snow                                             University of Akron Wayne CollegeLibrarianAmanda Rinehart                               Ohio State UniversityReview TeamJessica Hall                                        Ohio Dominican UniversitySanhita Gupta                                    Kent State UniversityErica Mersfelder                                 Sinclair Community College

Food provides the body with the nutrients it needs to survive. Many of these critical nutrients are biological macromolecules, or large molecules, necessary for life. Different smaller organic molecule (monomer) combinations build these macromolecules (polymers). What specific biological macromolecules do living things require? How do these molecules form? What functions do they serve? We explore these questions in this chapter.

Your body has many kinds of cells, each specialized for a specific purpose. Just as we use a variety of materials to build a home, the human body is constructed from many cell types. For example, epithelial cells protect the body's surface and cover the organs and body cavities within. Bone cells help to support and protect the body. Immune system cells fight invading bacteria. Additionally, blood and blood cells carry nutrients and oxygen throughout the body while removing carbon dioxide. Each of these cell types plays a vital role during the body's growth, development, and day-to-day maintenance. In spite of their enormous variety, however, cells from all organisms—even ones as diverse as bacteria, onion, and human—share certain fundamental characteristics.

Carl Woese and his colleagues proposed that all life on Earth evolved along three lineages, called domains. Two of the three domains—Bacteria and Archaea—are prokaryotic. Prokaryotes were the first inhabitants on Earth, appearing 3.5 to 3.8 billion years ago. These organisms are abundant and ubiquitous; that is, they are present everywhere. In addition to inhabiting moderate environments, they are found in extreme conditions: from boiling springs to permanently frozen environments in Antarctica; from salty environments like the Dead Sea to environments under tremendous pressure, such as the depths of the ocean; and from areas without oxygen, such as a waste management plant, to radioactively contaminated regions, such as Chernobyl. Prokaryotes reside in the human digestive system and on the skin, are responsible for certain illnesses, and serve an important role in the preparation of many foods.

The plasma membrane, the cell membrane, has many functions, but the most basic one is to define the cell's borders and keep the cell functional. The plasma membrane is selectively permeable. This means that the membrane allows some materials to freely enter or leave the cell, while other materials cannot move freely, but require a specialized structure, and occasionally, even energy investment for crossing.

Elements in various combinations comprise all matter, including living things. Some of the most abundant elements in living organisms include carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. These form the nucleic acids, proteins, carbohydrates, and lipids that are the fundamental components of living matter. Biologists must understand these important building blocks and the unique structures of the atoms that comprise molecules, allowing for cells, tissues, organ systems, and entire organisms to form. All biological processes follow the laws of physics and chemistry, so in order to understand how biological systems work, it is important to understand the underlying physics and chemistry. For example, the flow of blood within the circulatory system follows the laws of physics that regulate the modes of fluid flow. The breakdown of the large, complex molecules of food into smaller molecules—and the conversion of these to release energy to be stored in adenosine triphosphate (ATP)—is a series of chemical reactions that follow chemical laws. The properties of water and the formation of hydrogen bonds are key to understanding living processes. Recognizing the properties of acids and bases is important, for example, to our understanding of the digestive process. Therefore, the fundamentals of physics and chemistry are important for gaining insight into biological processes.

The Biology II Course was developed through the Ohio Department of Higher Education OER Innovation Grant. The course is part of the Ohio Transfer Assurance Guides and is also named OSC004. This work was completed and the course was posted in October 2019. For more information about credit transfer between Ohio colleges and universities, please visit: www.ohiohighered.org/transfer.Team LeadCathy Sistilli                                         Eastern Gateway Community CollegeContent ContributorsLisa Aschemeier                                 Northwest State Community CollegeShaun Blevins                                     Rhodes State CollegeRachel Detraz                                     Edison State Community College                                     Sara Finch                                          Sinclair Community CollegeWendy Gagliano                                 Clark State Community College AJ Snow                                             University of Akron Wayne CollegeLibrarianAmanda Rinehart                               Ohio State UniversityReview TeamJessica Hall                                        Ohio Dominican UniversitySanhita Gupta                                    Kent State UniversityErica Mersfelder                                 Sinclair Community College

Your body has many kinds of cells, each specialized for a specific purpose. Just as we use a variety of materials to build a home, the human body is constructed from many cell types. For example, epithelial cells protect the body's surface and cover the organs and body cavities within. Bone cells help to support and protect the body. Immune system cells fight invading bacteria. Additionally, blood and blood cells carry nutrients and oxygen throughout the body while removing carbon dioxide. Each of these cell types plays a vital role during the body's growth, development, and day-to-day maintenance. In spite of their enormous variety, however, cells from all organisms—even ones as diverse as bacteria, onion, and human—share certain fundamental characteristics.