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
Cell reproduction is a process of cell division that divides one cell into two identical cells. In multicellular organisms cell reproduction can be for growth, development or repair, whereas in single cell organisms it is a mechanism of reproduction. The focus of this content is the cell cycle in eukaryotic cells, regulation of the cell cycle, and consequences of a lack of regulation in the context of cancer. A summary of binary fission in prokaryotic cells is also included.
Meiosis is the process of cell division that produces haploid gametes. In sexual reproduction haploid gametes combine through fertilization to form a genetically recombined diploid zygote. Meiosis includes two successive divisions and processes such as crossing over and independent assortment that increase genetic variability in gametes produced. Life cycles detail the events between meiosis and fertilization that vary for different multicellular organisms.
Genetics is the study of heredity. Johann Gregor Mendel set the framework for genetics long before chromosomes or genes had been identified, at a time when meiosis was not well understood. Mendel selected a simple biological system and conducted methodical, quantitative analyses using large sample sizes. Because of Mendel’s work, the fundamental principles of heredity were revealed. We now know that genes, carried on chromosomes, are the basic functional units of heredity with the capability to be replicated, expressed, or mutated. Today, the postulates put forth by Mendel form the basis of classical, or Mendelian, genetics. Not all genes are transmitted from parents to offspring according to Mendelian genetics, but Mendel’s experiments serve as an excellent starting point for thinking about inheritance.
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.