The Cell: a Very Short Introduction by
All living things on Earth are composed of cells. A cell is the simplest unit of a self-contained living organism, and the vast majority of life on Earth consists of single-celled microbes, mostly bacteria. These consist of a simple "prokaryotic" cell, with no nucleus. The bodies of morecomplex plants and animals consist of billions of "eukaryotic" cells, of varying kinds, adapted to fill different roles - red blood cells, muscle cells, branched neurons. Each cell is an astonishingly complex chemical factory, the activities of which we have only begun to unravel in the past fiftyyears or so through modern techniques of microscopy, biochemistry, and molecular biology.In this Very Short Introduction, Terrence Allen and Graham Cowling describe the nature of cells - their basic structure, their varying forms, their division, their differentiation from initially highly flexible stem cells, their signalling, and programmed death. Cells are the basic constituent oflife, and understanding cells and how they work is central to all biology and medicine.
The Cell by
Studying the cell helps us improve our understanding of the living world, plant and animal physiology, genetics, and biochemistry. This wealth of information has revolutionized the biological and medical sciences, leading to a dramatic reduction in mortalities due to infectious diseases and medical disorders. The war on cancer—launched almost 40 years ago—is finally approaching a stage where all cancers will be curable. Improved treatment and prognosis is now possible for many other disorders, such as cardiovascular disease, diabetes, and cystic fibrosis. Improved knowledge of the cell has made it possible for researchers to isolate and culture stem cells, which may be used to treat spinal cord trauma and degenerative neurological diseases such as Alzheimer's and Parkinson's disease. The Cell, Revised Edition contains new and revised material throughout, accompanied by many photographs and line drawings, all of which are now in color. Updated chapters in this timely resource now cover the recent controversy over the teaching of creationism in public schools, life on other planets, bacterial populations, and the potential threat of certain pathogenic species, as well as a more detailed discussion of eukaryote structure and function. New chapters have been added on the many cells that make up the human body as well as the crucial role that photosynthesis plays during the formation of the Earth's biosphere.
The Cell by
Understanding the cell is the key to grasping the significant potential and technological developments of the new biology. Presented from the point of view of the cell's motivations, The Cell presents the origins and mechanisms of this element of life and the development of scientific knowledge surrounding it.
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All living things are made of cells. Cells are microscopic; first discovered in 1665. Cells are surrounded by a membrane.
1) Prokaryotic cells - in bacteria. They have a simple structure (no nucleus or organelles). They are small (1 - 5 micrometers across). Usually have an external cell wall.
2) Eukaryotic cells - in plants, fungi, animals. The DNA is organized into chromosomes in the nucleus. They have specialized organelles and are larger (10 - 50 micrometers across). Prokaryotes and Eukaryotes
Microscopes
1) Light microscopes - focus light on the specimen. Advantages: living cells, color, portable, cheap. Disadvantage : magnification only up to 1000.
2) Electron microscopes - focus a beam of electrons on the specimen. Advantage : high magnification (up to 1 million ) Disadvantages : dead cells, black/white, not portable, expensive.
The Cell
Why are cells so small? They need to keep a large surface area compared to volume. Cells consist of : membrane, nucleus and cytoplasm.
Nucleus: roughly 5 micrometers across. It contains genes (DNA) arranged in chromosomes, and is surrounded by nuclear membrane which has pores. The nucleolus (inside the nucleus) produces ribosomes.
Cytoplasm : contains many organelles
Organelles
1). Ribosomes : are made of RNA and protein. Ribosomes use RNA to produce proteins.
2). ER (Endoplasmic reticulum)