Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Cell division in eukaryotes

Cell division in eukaryotes occurs in four well-defined stages (Fig. 12-41). In the S (synthesis) phase, the DNA is replicated to produce copies for both daughter... [Pg.466]

Mitosis and cell division in eukaryotes. After DNA duplication has occurred, mitosis is the process by which quantitatively and qualitatively identical DNA is delivered to daughter cells formed by cell division. Mitosis is traditionally divided into a series of stages characterized by the appearance and movement of the DNA-bearing structures, the chromosomes. (a) Premitosis, (b) through (h) Successive stages of mitosis, (/) Postmitosis. [Pg.24]

The cellular structure is dynamic. The most dramatic changes occur when a cell divides into two daughter cells as part of the process of cell proliferation. Cell division in eukaryotes involves the process of mitosis in which the nuclear membrane dissolves, the chromosomes condense and separate into two groups, and two nuclear membranes reassemble around the chromosomes. Finally, in the process of cytokinesis, the cell membrane contracts in the middle to form a shape like the character "8" and the two halves separate to form independent cells. Although it is the most dramatic of the microscopically visible events, the division itself is just part of a complete cycle of molecular events in which the cell prepares for division and then carries it out (Fig. 1.3). [Pg.50]

No events have been described which uniquely characterize the G1 phase. The G1 phase appears to perform two functions the temporary or permanent arrest of cell division in eukaryotes is normally achieved by cells maintaining themselves in the G1 phase of the cell cycle (Prescott, 1970) also the terminal part of the G1 must contain events concerned with the initiation of DNA synthesis. Certain organisms, for example, the fission yeast Schizosaccharomyces pombe (Bostock et al., 1966), the multinucleate slime mold Physarum polycephalum (Guttes et al., 1967), and Amoeba proteus (Ord, 1968), do not exhibit a G1 phase. A number of mammaUan cells appear to lack a G1... [Pg.4]

Bradbury, E. M., Inglis, R. J., Matthews, H. R., and Langan, T. A., 1974a, Molecular basis of control of mitotic cell division in eukaryotes. Nature 249 553. [Pg.286]

Mitosis the process of nuclear division in eukaryotic cells. [Pg.396]

From the complementary duplex structure of DNA described in chapter 25, it is a short intuitive hop to a model for replication that satisfies the requirement for one round of DNA duplication for every cell division. In chapter 26, DNA Replication, Repair, and Recombination, key experiments demonstrating the semiconservative mode of replication in vivo are presented. This is followed by a detailed examination of the enzymology of replication, first for how it occurs in bacteria and then for how it occurs in animal cells. Also included in this chapter are select aspects of the metabolism of DNA repair and recombination. The novel process of DNA synthesis using RNA-directed DNA polymerases is also considered. First discovered as part of the mechanisms for the replication of nucleic acids in certain RNA viruses, this mode of DNA synthesis is now recognized as occurring in the cell for certain movable genetic segments and as the means whereby the ends of linear chromosomes in eukaryotes are synthesized. [Pg.993]

Cytoskeleton is defined as the sum of the various filamentous proteins of eukaryotic cells that remain after the cells are extracted with a mild detergent. The cytoskeleton includes actin filaments, two-stranded helical polymers, which form the microfilaments and the actin-binding proteins. Other components are microtubules and intermediate filaments. The cytoskeleton has not only a role in maintaining the shape of cells, it is also actively engaged in cell division, in the organisation and the dynamic movement of ceD organelles and in the movement of cells in chemotaxis. [Pg.308]

Cell division in bacteria and eukaryotes takes place in precisely the same manner. [Pg.36]

Recombination occurs primarily in germ cells of eukaryotes and during cell division in partially diploid prokaryotes. In general, recombination does not occur in mitosis of eukaryotic cells. However, recombination is an integral part of meiosis in which recombinant sperm and ova provide new genotypes and phenotypes in each generation which may be favored by natural selection. [Pg.545]

Timing of replication. In contrast to rapidly growing bacterial cells, in which replication occurs throughout most of the cell division cycle, eukaryotic replication is limited to a specific period referred to as the S phase (Figure 18.9). It is now known that eukaryotic cells produce certain proteins (Section 18.3) that regulate phase transitions within the cell cycle. [Pg.621]

There are two forms of recombination general and site-specific. General recombination, which occurs between homologous DNA molecules, is most commonly observed during meiosis. (Recall that meiosis is the form of eukaryotic cell division in which haploid gametes are produced.) A similar process has been observed... [Pg.625]

In comparing results obtained in yeast of mammalian results it should be remembered that there are significant differences in cell division in fungi compared to higher eukaryotes. There are now numerous chemicals that are capable of inducing chromosomal malsegregation in various test systems involving different results. [Pg.152]

The DNA in a eukaryotic cell nucleus during the interphase between cell divisions exists as a nucleoprotein complex called chromatin. The proteins of chromatin fall into two classes histones and nonhistone chromosomal proteins. [Pg.379]

A three-dimensional meshwork of proteinaceous filaments of various sizes fills the space between the organelles of all eukaryotic cell types. This material is known collectively as the cytoskeleton, but despite the static property implied by this name, the cytoskeleton is plastic and dynamic. Not only must the cytoplasm move and modify its shape when a cell changes its position or shape, but the cytoskeleton itself causes these movements. In addition to motility, the cytoskeleton plays a role in metabolism. Several glycolytic enzymes are known to be associated with actin filaments, possibly to concentrate substrate and enzymes locally. Many mRNA species appear to be bound by filaments, especially in egg cells where they may be immobilized in distinct regions thereby becoming concentrated in defined tissues upon subsequent cell divisions. [Pg.85]


See other pages where Cell division in eukaryotes is mentioned: [Pg.410]    [Pg.404]    [Pg.58]    [Pg.37]    [Pg.363]    [Pg.231]    [Pg.284]    [Pg.125]    [Pg.410]    [Pg.404]    [Pg.58]    [Pg.37]    [Pg.363]    [Pg.231]    [Pg.284]    [Pg.125]    [Pg.466]    [Pg.219]    [Pg.21]    [Pg.1108]    [Pg.134]    [Pg.136]    [Pg.271]    [Pg.113]    [Pg.11]    [Pg.427]    [Pg.452]    [Pg.731]    [Pg.113]    [Pg.368]    [Pg.16]    [Pg.328]    [Pg.328]    [Pg.333]    [Pg.230]    [Pg.394]    [Pg.535]    [Pg.648]    [Pg.46]    [Pg.173]    [Pg.4]   
See also in sourсe #XX -- [ Pg.150 ]




SEARCH



Eukaryotes cells 279

Eukaryotic cell division

Eukaryotic cells

© 2024 chempedia.info