A grasp of the logic and practice of science is essential to understand the rest of the world around us. To that end, the CMB3e iText (like earlier editions) remains focused on experimental support for what we know about cell and molecular biology, and on showing students the relationship of cell structure and function. Rather than trying to be a comprehensive reference book, CMB3e selectively details investigative questions, methods and experiments that lead to our understanding of cell biology. This focus is nowhere more obvious than in the chapter learning objectives and in external links to supplementary material. The Basic CMB3e version of the iText includes links to external web-sources as well as the author’s short, just-in-time YouTube VOPs (with edited, optional closed captions), all embedded in or near relevant text. Each video is identified with a descriptive title and video play and QR bar codes.

We are happy to welcome you to our second Open Educational Resource (OER) textbook, Biochemistry Free For All. Biochemistry is a relatively young science, but its rate of growth has been truly impressive. The rapid pace of discoveries, which shows no sign of slowing, is reflected in the steady increase in the size of biochemistry textbooks. Growing faster than the size of biochemistry books have been the skyrocketing costs of higher education and the even faster rising costs of college textbooks. These unfortunate realities have created a situation where the costs of going to college are beyond the means of increasing numbers of students.

Our goal is to present the key observations and unifying concepts upon which modern biology is based; it is not a survey of all biology! Once understood, these foundational observations and concepts should enable you to approach any biological process, from disease to kindness, from a scientific perspective. To understand biological systems we need to consider them from two complementary perspectives; how they came to be (the historic, that is, evolutionary) and how their structures, traits, and behaviors are produced (the mechanistic, that is, the physicochemical)

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.

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.

Plants and animals must take in and transform energy for use by cells.  Plants, through photosynthesis, absorb light energy and form organic molecules such as glucose.  Glucose has potential energy in the form of chemical energy stored in its bonds.  This chapter covers the metabolic pathways of cellular respiration and describes the chemical reactions that use energy in glucose and other organic molecules to form adenosine triphosphate (ATP).  ATP is the cell’s “energy currency” fueling virtually all energy requiring processes.  The chemical reactions of cellular respiration are a series of oxidation- reduction (redox) reactions that are divided into three stages: glycolysis, the citric acid cycle and oxidative phosphorylation.    

The theory of evolution is the unifying theory of biology, meaning it is the framework within which biologists ask questions about the living world. Its power is that it provides direction for predictions about living things that are borne out in ongoing experiments. The Ukrainian-born American geneticist Theodosius Dobzhansky famously wrote that “nothing makes sense in biology except in the light of evolution.” He meant that the tenet that all life has evolved and diversified from a common ancestor is the foundation from which we approach all questions in biology.

This chapter outlines information on the regulation of gene expression in both prokaryotes and eukaryotes.  This includes transcriptional, post-transcriptional, translational and post-translational regulation.  

IntroductionThis chapter covers the details of the Central dogma including transcription and translation.  Prokaryotic and eukaryotic transcription are compared. Eukaryotic RNA processing is described.  Protein synthesis is outlined including protein folding and modifications of the newly created proteins.