Chapter 1: Stem Cells and Their Differentiation

Cell and Tissue Structure and Organization Unity of plan everywhere lies hidden under the mask of diversity of structure—the complex is everywhere evolved out of the simple. —Thomas Henry Huxley A Lobster; or, the Study of Zoology (1861). In: Collected Essays, Vol. 8. 1894: 205–206. The most basic and simple form of human life is […]

Chapter 2: Extracellular Matrix and Cell Adhesion

OVERVIEW Cells are organized into groups or aggregates, known as tissues, that perform one or more specific functions. Tissues, in turn, create a stable environment in which the cells live and function. Unlike epithelial, muscle, and nerve tissues which are composed principally of cells, connective tissue contains a matrix of macromolecules in the extracellular space. […]

Chapter 3: Biological Membranes

OVERVIEW Membranes are the outer boundary of individual cells and of certain organelles. Plasma membranes are the selectively permeable outermost structures of cells that separate the interior of the cell from the environment. Certain molecules are permitted to enter and exit the cell through transport across the plasma membrane. Cell membranes contain lipids and proteins […]

Chapter 4: Cytoskeleton

OVERVIEW The cytoskeleton is a complex network of protein filaments that establish a supportive scaffolding system within the cell (Figure 4.1). Cytoskeletal proteins are located throughout the interior of the cell, anchored to the plasma membrane, the outer boundary of the cell, and traversing the cytoplasm (the interior contents of the cell bound by the […]

Chapter 5: Organelles

OVERVIEW Organelles are complex intracellular locations where processes necessary for eukaryotic cellular life occur. Most organelles are membrane-enclosed structures. Their membranes are composed of the same components as plasma membranes that form the outer boundaries of cells (see Chapter 3). Together with the cytosol (liquid portion of the cytoskeleton), the organelles help to form the […]

Chapter 6: The Eukaryotic Genome

Organization of the Eukaryotic Genome and Gene Expression They are in you and me; they created us, body and mind; and their preservation is the ultimate rationale for our existence… they go by the name of genes, and we are their survival machines. —Richard Dawkins (English biologist, 1941–) In: The Selfish Gene (1976) Human genetic […]

Chapter 7: DNA Replication

OVERVIEW Deoxyribonucleic acid (DNA) contains all the information necessary for the development and function of all organisms. The replication or copying of cellular DNA occurs during the S or synthesis phase of the cell cycle (see Chapter 20). This is a necessary process to ensure that the instructions in DNA are faithfully passed on to […]

Chapter 8: Transcription

OVERVIEW Genes are considered expressed when information contained within deoxyribonucleic acid (DNA) affects the cell’s properties and activities. Ribonucleic acid (RNA) mediates gene expression. Generally, every gene contains two classes of information, one specifies the primary structure of the final product and the other is critical for regulated expression of the gene’s products. Both the […]

Chapter 9: Translation

OVERVIEW Genetic information, stored in the chromosomes and transmitted to daughter cells through DNA replication, is expressed through transcription to RNA and, in the case of mRNA, subsequent translation into proteins (Figure 9.1). The pathway of protein synthesis is called translation because the “language” of the nucleotide sequence on the mRNA is translated into the […]

Chapter 10: Regulation of Gene Expression

OVERVIEW The DNA sequence within each somatic cell contains the information required to synthesize thousands of different proteins and RNA molecules. Typically, a cell expresses only a fraction of its genes. Different cell types in multicellular organism arise because each type expresses a different set of genes. Moreover, cells can change the pattern of genes […]