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Lysosome animal cell

It is a very large vesicle enclosed by a single membrane called the tonoplast. Vacuoles tend to be smaller in young cells, but in mature cells, they may occupy more than 50% of the cell s volume. Vacuoles occupy the center of the cell, with the cytoplasm being located peripherally around it. They resemble the lysosomes of animal cells. [Pg.29]

In spite of the variety of appearances of eukaryotic cells, their intracellular structures are essentially the same. Because of their extensive internal membrane structure, however, the problem of precise protein sorting for eukaryotic cells becomes much more difficult than that for bacteria. Figure 4 schematically illustrates this situation. There are various membrane-bound compartments within the cell. Such compartments are called organelles. Besides the plasma membrane, a typical animal cell has the nucleus, the mitochondrion (which has two membranes see Fig. 6), the peroxisome, the ER, the Golgi apparatus, the lysosome, and the endosome, among others. As for the Golgi apparatus, there are more precise distinctions between the cis, medial, and trans cisternae, and the TGN trans Golgi network) (see Fig. 8). In typical plant cells, the chloroplast (which has three membranes see Fig. 7) and the cell wall are added, and the lysosome is replaced with the vacuole. [Pg.302]

A successful tool in the early studies of metabolic pathways was blocking the pathway at some specific point. This could be done by the use of either mutants or inhibitors. Schekman et al have isolated a number of yeast mutants with blocks in their secretion pathway (Schekman, 1982). It is not yet known which proteins these mutations affect, but this is clearly a most promising approach for identifying those components involved in transport. In animal cells there are no cellular mutants with blocks in the intracellular transport of protein from the ER to the cell surface. There are, however, genetic diseases which affect the routing of lysosomal enzymes to the lysosomes (Neufeld et al, 1975 Sly and Fischer, 1982). For viruses it has been possible to isolate temperature-sensitive mutants in which a mutation in the viral glycoprotein arrests... [Pg.116]

The most important membranes in animal cells are the plasma membrane, the inner and outer nuclear membranes, the membranes of the endoplasmic reticulum (ER) and the Golgi apparatus, and the inner and outer mitochondrial membranes. Lysosomes, peroxisomes, and various vesicles are also separated from the cytoplasm by membranes. In plants, additional membranes are seen in the plastids and vacuoles. All membranes show polarity—e., there is a difference in the composition of the inner layer (facing toward the cytoplasm) and the outer layer (facing away from it). [Pg.216]

Animal lysosomes are organelles with a diameter of 0.2-2.0 xm with various shapes that are surrounded by a single membrane. There are usually several hundred lysosomes per cell. ATP-driven V-type proton pumps are active in their membranes (see p. 220). As these accumulate in the lysosomes, the content of lysosomes with pH values of 4.5-5 is much more acidic than the cytoplasm (pH 7-7.3). [Pg.234]

Acid deoxyribonuclease (DNase) is an enzyme which splits the phosphodiester bonds of native DNA by both a diplotomic and a haplotomic mechanism (see Section 111,0) leaving the terminal phosphate in a 3 position. The enzyme is very widely distributed in animal cells and appears to be localized in the lysosomes. The best known acid DNase is that from hog spleen this explains why most of the data presented here refer to this enzyme. It should be stressed, however, that the properties of acid DNases obtained from the tissues of other vertebrates appear to be extremely similar to those of the hog spleen enzyme ... [Pg.271]

Lysosomes in animal cells are bounded by a single membrane. They have an acidic internal pH (pH 4-5), maintained by proteins in the membrane that pump in H+ ions. Within the lysosomes are acid hydrolases enzymes involved in the degradation of macromolecules, including those internalized by endocytosis. [Pg.5]

A eukaryotic cell is surrounded by a plasma membrane, has a membrane-bound nucleus and contains a number of other distinct subcellular organelles (Fig. 1). These organelles are membrane-bounded structures, each having a unique role and each containing a specific complement of proteins and other molecules. Animal and plant cells have the same basic structure, although some organelles and structures are found in one and not the other (e.g. chloroplasts, vacuoles and cell wall in plant cells, lysosomes in animal cells). [Pg.5]

Plant cell vacuole Plant cells usually contain one or more membrane-bounded vacuoles. These are used to store nutrients (e.g. sucrose), water, ions and waste products (especially excess nitrogen-containing compounds). Like lysosomes in animal cells, vacuoles have an acidic pH maintained by H+ pumps in the membrane and contain a variety of degradative enzymes. Entry of water into the vacuole causes it to expand, creating hydrostatic pressure (turgor) inside the cell which is balanced by the mechanical resistance of the cell wall. [Pg.9]

These authors suggest that the multivalency of the lectins is an important factor in vacuole formation in these cells. However, we have seen that two of those lectins most active in the macrophage system, namely concanavalin A and wheat germ agglutinin, are unable to induce lysosomes in cultured fibroblasts. We are presently studying the properties of the lectins and the cells in order to more coiqpletely understand the mechanism of lectin induced accumulation of lysosomes in animal cells. [Pg.64]

Main intracellular compartments of an animal cell. Cytosol, endoplasmic reticulum, Golgi complex, nucleus, mitochondria, endosome, lysosome, and peroxisome are distinct compartments that are isolated from the rest of the cell by at least one selective membrane. [Pg.14]

Most animal cells contain lysosomes, which have a single limiting membrane and contain a variety of hydrolases (some 40 enzymes) used for the controlled in-... [Pg.9]

Ml. Maggi, V., Lysosomal and non-lysosomal localization of acid hydrolases in animal cells. Biochem. J. Ill, 25P-26P (1969). [Pg.143]

CuZnSOD is present mainly in the cytoplasm of animal cells but was also detected in lysosomes, peroxisomes, nucleus, and intermembrane space of mitochondria [1,2]. MnSOD is located in the matrix space of mitochondria [3]. However, in decapod Crustacea, which contain no CuZnSOD, MnSOD is present both in the mitochondria and in the cytosol [4]. EC-SOD is a secretory form of SOD present on the surface of many cells and outside the cells in blood plasma, lymph, ascites, and cerebrospinal fluid. However, the primary location of EC-SOD in tissues is the extracellular matrix and on cell surfaces where it is found at 20 times the concentration present in blood plasma. Tissue EC-SOD is thought to account for 90-99% of the EC-SOD of the body [5,6]. The content of EC-SOD is the highest in blood vessels, epididymis, heart, lung, kidney, testis, Sertoli and germ cells, and uterus [5, 6]. EC-SOD is also synthesized and secreted by a... [Pg.110]

Figure 1 Major intracellular compartments in an animal cell. 1. Nucleus 2. cytosol 3. mitochondrion 4. lysosome ... Figure 1 Major intracellular compartments in an animal cell. 1. Nucleus 2. cytosol 3. mitochondrion 4. lysosome ...
Lysosomes provide an excellent example of the ability of Intracellular membranes to form closed compartments in which the composition of the lumen (the aqueous Interior of the compartment) differs substantially from that of the surrounding cytosol. Found exclusively in animal cells,... [Pg.165]

The structures of F class and V class ion pumps are sIm liar to one another but unrelated to and more complicated than P-class pumps. F- and V-class pumps contain several different transmembrane and cytosolic subunits. All known V and F pumps transport only protons. In a process that does not Involve a phosphoprotein Intermediate. V-class pumps generally function to maintain the low pH of plant vacuoles and of lysosomes and other acidic vesicles In animal cells by pumping protons from the cytosolic to the exoplasmic face of the membrane against a proton electrochemical gradient. F-class pumps are found In bacterial plasma membranes and In mitochondria and chloroplasts. In contrast to V pumps, they generally function to power the synthesis of ATP from ADP and Pj by movement of protons from the exoplasmic to the cytosolic face of the membrane down the proton electrochemical gradient. Because of their Importance In ATP synthesis in chloroplasts and mitochondria, F-class proton pumps, commonly called ATP synthases, are treated separately In Chapter 8. [Pg.253]

Thus, the data from both bacteria and animal cells demonstrate that transbilayer movement of phospholipid occurs on a timescale of minutes, in an ATP-independent fashion in membranes that contain the majority of the enzymes involved in their biosynthesis. These intramembrane transport properties observed in the major biosynthetic membranes, however, are not generally true for other membrane systems. This is especially true of the plasma membrane, Golgi, endosomal, and lysosomal membranes. [Pg.452]

Cathepsins. Intracellular proteinascs obtained Irom animal tissue extracts, the richest sources being liver, kidney and spleen. Located primarily in the lysosomal fraction within the cell. Part of the genera] enzymic apparatus of animal cells in most cases they do not specialize in functions characteristic of individual tissues. Review of cathepsins A -C J. S, Fruton in The Enzymes vol, 4, P. D. Boyer et at., Eds. (Academic Press, New York, I960) pp 233-241 of cathepsins A-E M. J. Mycek, Methods JEnzymol. 19, 285-315 (1970) of cathepsins B, D and G several authors, Res. Monogr. Celt Tissue Physiol. 2, 57-89, 181 -248 (1977) of cathepsins B, D, G, H, L, N and S several authors, Ciba Found. Symp. 75, 1-68 (1980). [Pg.291]

In many respects the basic features of amino acid and protein metabolism of parasitic protozoa and helminths resemble those of their mammalian hosts. Proteins can be broken down extracellularly or within lysosomes, and amino acids taken up and used for biosynthesis or energy metabolism. The pathways of amino acid metabolism are mostly the same as those used by animal cells. There are, nevertheless, some significant differences. Although no unique class of proteinase has been found in either protozoa or helminths, differences in specificity between parasite and host enzymes mean that inhibitors can be designed which selectively inactivate parasite enzymes. Because proteolysis is so important to many parasites at various stages of their life cycle, proteinase inhibitors are being studied and tested as potential antiparasitic agents... [Pg.83]

Lysosomes are found mainly in animal cells. These contain digestive enzymes that break down food, substances not needed, viruses, damaged cell components and eventually the cell itself. It is believed that lysomomes are responsible for the aging process. [Pg.44]

Bacteria and other prokaryotes lack the complex intracellular structures (endoplasmic reticulum, Golgi apparatus, lysosomes, mitochondria, etc.) found in plant and animal cells (eukaryotes). Bacterial morphology (shape and size) is limited to... [Pg.203]


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