Molecular Biology of the Cell
All living creatures are made of cells – small membrane-bounded compartments filled with a concentrated aqueous solution of chemicals. The simplest forms of life are solitary cells that propagate by dividing in two.
Higher organisms, such as ourselves, are like cellular cities in which groups of cells perform specialized functions and are linked by intricate systems of communication. Cells occupy a halfway point in the scale of biological complexity. We study them to learn, on the one hand, how they are made from molecules and, on the other, how they cooperate to make an organism as complex as a human being.
All organisms, and all of the cells that constitute them, are believed to have descended from a common ancestor cell through evolution by natural selection This involves two essential processes: (1) the occurrence of random variation in the genetic information passed from an individual to its descendants and (2) selection in favor of genetic information that helps its possessors to survive and propagate Evolution is the central principle of biology, helping us to make sense of the bewildering variety in the living world.
This book is concerned with the progression from molecules to multicellular organisms. It discusses the evolution of the cell, first as a living unit constructed from smaller parts and then as a building block for larger structures. Through evolution, we introduce the cell components and activities that are to be treated in detail, in broadly similar sequence, in the chapters that follow.
Beginning with the origins of the first cell on earth, we consider how the properties of certain types of large molecules allow hereditary information to be transmitted and expressed and permit evolution to occur. Enclosed in a membrane, these molecules provide the essentials of a self-replicating cell.
Following this, we describe the major transition that occurred in the course of evolution, from small bacteriumlike cells to much larger and more complex cells such as are found in present-day plants and animals. Lastly, we suggest ways in which single free-living cells might have given rise to large multicellular organisms, becoming specialized and cooperating in the formation of such intricate organs as the brain.
- The Evolution of the Cell
- Small Molecules, Energy, and Biosynthesis
- Macromolecules: Structure, Shape, and Information
- How Cells Are Studied
- Protein Function
- Basic Genetic Mechanisms
- Recombinant DNA Technology
- The Cell Nucleus
- Control of Gene Expression
- Membrane Structure
- Membrane Transport of Small Molecules and the Ionic Basis of Membrane Excitability
- Intracellular Compartments and Protein Sorting
- Vesicular Traffic in the Secretory and Endocytic Pathways
- Energy Conversion: Mitochondria and Chloroplasts
- Cell Signaling
- The Cytoskeleton
- The Cell-Division Cycle
- The Mechanics of Cell Division
- The Immune System
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