Cells, animal chemical composition

Fats and oils, constituted by acylglycerolipids, represent a major subgroup of lipids. They are the most common class of medium-size molecules produced by living organisms. They are the main constituents of the storage fat cells in plants and animals. They have quite a similar chemical composition, as they are mainly composed of triglycerides, triesters of glycerol with fatty acids (FAs). 

Generalized representations of the internal structures of animal and plant cells (eukaryotic cells). Cells are the fundamental units in all living systems, and they vary tremendously in size and shape. All cells are functionally separated from their environment by the plasma membrane that encloses the cytoplasm. Plant cells have two structures not found in animal cells a cellulose cell wall, exterior to the plasma membrane, and chloroplasts. The many different types of bacteria (prokaryotes) are all smaller than most plant and animal cells. Bacteria, like plant cells, have an exterior cell wall, but it differs greatly in chemical composition and structure from the cell wall in plants. Like all other cells, bacteria have a plasma membrane that functionally separates them from their environment. Some bacteria also have a second membrane, the outer membrane, which is exterior to the cell wall. 

There are several manufacturers of microcarriers for animal cell culture, providing products with different chemical composition, size, form, and density. Table 9.2 shows a list of common commercially available microcarriers and their manufacturers. 

The unique immunological and bacteriological properties of Mycobacterium tuberculosis have stimulated a great deal of research into the chemical composition of the cell and its associated substances. The initial impetus to these extensive investigations was given by Koch, who prepared various bacillary extracts and showed that these were able to stimulate specific reactions in infected animals. 

Keratins - ot-Keratins are the major proteins of hair and fingernails and a compose a major fraction of animal skin, oi-keratins are classified in the broad group of intermediate filament proteins, which play important structural roles in nuclei, cytoplasm, and cell surfaces. Their secondary structure is composed predominantly of -helices. Figure 6.11 shows the coiled-coil structure of the ot-keratin in hair. The chemical composition of the cysteine residues in ot-keratin affects its macromolecular structure and function. For example, hair has relatively few cysteine cross-links, whereas fingernails have many such cross-links, / -keratins, on the other hand, contain much more pleated sheet secondary strucure than ot-keratins and are found in feathers and scales. 

Natural water is an aqueous solution of gases, ions and molecules, but it also contains undissolved, suspended and/or colloidal inorganic particles of different size and chemical composition and biogenic living and/or dead matter such as cells, plants, and animals etc., sometimes termed hydrosol. Water occurs in the climate system in different forms ... 

The membranes ofplant cells are remarkably like those of animals. The plasma membrane of plants seems not to offer so great a barrier as that of the mitochondria, or of the cytoplasmic reticulum, or of the vacuole (a feature absent in animals). Most, if not all, movement into plant roots is physical diffusion unaided by biochemical processes. The plasma membrane of roots seems to have a special structure with unusual selectivity. Maleic hydrazide causes chromosome breakages in plant cells, but not in mammalian cells. As mammalian and plant chromosomes have the same chemical composition, a difference in permeability is indicated (Barnes etaL, 1957). 

To achieve delivery of this high cell number in close proximity to a capillary network, we needed to provide a scaffold with an immense surface area. In this context, we began to address the question of growth of multicellular organisms. The surface area of a mass of cells increases as the square of the radius, while the volume increases as the cube of the radius. In experiments involving several hundred animals, we employed branching networks of biocompatible, biodegradable polymers of several chemical compositions and physical characteristics as matrices onto which we seeded hepatocytes. 

The carbon-autotrophic green plant is the primary producer of carbohydrates on the earth and uses carbohydrates extensively as storage and cell-wall substances (starch, cellulose, etc). The nitrogen-hetero-trophic animal usually consumes a rather protein-rich diet and uses proteins as supportive materials The approximate chemical composition of the human body is shown in Table 2. Most of the mass of bacteria (see Escherichia coli) is made up by proteins, which may account for 70 % of the dry weight. Numerically,... 

Breitenstein, D., Rommel, C.E., Mollers, R., Wegener, J., Hagenhoft B. (2008) The chemical composition of animal cells and their intracellular compartments reconstructed from 3D mass spectrometry. Angew. Chem. Int. Ed. Engl, 46,5332-5335. 

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