cell division

Examples of cell division in the following topics:

• Fts Proteins and Cell Division

  • L-form bacteria that lack a cell wall do not require FtsZ for division, which implies that bacteria may have retained components of an ancestral mode of cell division.
  • The hypothesis was that cell division mutants of E. coli would grow as filaments due to the inability of the daughter cells to separate from one another.
  • During cell division, FtsZ is the first protein to move to the division site, and is essential for recruiting other proteins that produce a new cell wall between the dividing cells.
  • FtsZ's role in cell division is analogous to that of actin in eukaryotic cell division, but unlike the actin-myosin ring in eukaryotes, FtsZ has no known motor protein associated with it.
  • It is interesting to note that L-form bacteria that lack a cell wall do not require FtsZ for division, which implies that bacteria may have retained components of an ancestral mode of cell division.

• Cancer Viruses

  • Viruses can cause cancer by transforming a normal cell into a malignant cell.
  • Cancer cells have characteristics that differ from normal cells, such as acquiring the ability to grow uncontrollably.
  • Cancer cells don't experience biological aging, and maintain their ability to undergo cell division and growth.
  • Transformation occurs when a virus infects and genetically alters a cell.
  • The tumor viruses or oncoviruses change cells by integrating their genetic material with the host cell's DNA .

• Peptidoglycan Synthesis and Cell Division

  • That is why the cell wall of Archaea is insensitive to lysozyme.
  • A common misconception is that peptidoglycan gives the cell its shape.
  • However, it is actually the MreB protein that facilitates cell shape.
  • Peptidoglycan is also involved in binary fission during bacterial cell reproduction.
  • Simplified sc hematic of a cell wall in a Gram-positive bacteria

• Caulobacter Differentiation

  • A Caulobacter is used for studying the regulation of the cell cycle, asymmetric cell division, and cellular differentiation.
  • Caulobacter is an important model organism for studying the regulation of the cell cycle, asymmetric cell division, and cellular differentiation.
  • Swarmer cells differentiate into stalked cells after a short period of motility.
  • Chromosome replication and cell division only occurs in the stalked cell stage.
  • The isolated swarmer cells can then be grown as a synchronized cell culture.

• Centrosome

  • During the prophase in the process of cell division called mitosis, the centrosomes migrate to opposite poles of the cell.
  • Upon division, each daughter cell receives one centrosome.
  • The function of centrosome in this context is hypothesized to ensure the fidelity of cell division because it greatly increases the efficacy.
  • During the prophase in the process of cell division called mitosis, the centrosomes migrate to opposite poles of the cell.
  • Upon division, each daughter cell receives one centrosome.

• Morphologically Unusual Proteobacteria

  • Caulobacter is an important model organism for studying the regulation of the cell cycle, asymmetric cell division, and cellular differentiation.
  • One daughter is a mobile "swarmer" cell that has a single flagellum at one cell pole that provides swimming motility for chemotaxis.
  • Swarmer cells differentiate into stalked cells after a short period of motility.
  • Chromosome replication and cell division only occurs in the stalked cell stage.
  • Swarmer cells differentiate into stalked cells after a short period of motility.

• Generation Time

  • Bacterial growth occurs by the division of one bacterium into two daughter cells in a process called binary fission.
  • Bacterial growth is the division of one bacterium into two daughter cells in a process called binary fission.
  • Both daughter cells from the division do not necessarily survive.
  • The slope of this line is the specific growth rate of the organism, which is a measure of the number of divisions per cell per unit time.
  • The actual rate of this growth (i.e. the slope of the line in the figure) depends upon the growth conditions, which affect the frequency of cell division events and the probability of both daughter cells surviving.

• Virus Attachment and Genome Entry

  • Viral populations do not grow through cell division, because they are acellular.
  • This is often called "viral entry. " The infection of plant and fungal cells is different from that of animal cells.
  • Plants have a rigid cell wall made of cellulose, and fungi one of chitin, so most viruses can get inside these cells only after trauma to the cell wall.
  • Bacteria, such as plants, have strong cell walls that a virus must breach to infect the cell.
  • However, given that bacterial cell walls are less thick than plant cell walls due to their much smaller size, some viruses have evolved mechanisms that inject their genome into the bacterial cell across the cell wall, while the viral capsid remains outside

• Inhibiting Cell Wall Synthesis

  • Antibiotics commonly target bacterial cell wall formation (of which peptidoglycan is an important component) because animal cells do not have cell walls.
  • Diagram depicting the failure of bacterial cell division in the presence of a cell wall synthesis inhibitor (e.g. penicillin, vancomycin).1- Penicillin (or other cell wall synthesis inhibitor) is added to the growth medium with a dividing bacterium.2- The cell begins to grow, but is unable to synthesize new cell wall to accommodate the expanding cell.3- As cellular growth continues, cytoplasm covered by plasma membrane begins to squeeze out through the gap(s) in the cell wall.4- Cell wall integrity is further violated.
  • The cell continues to increase in size, but is unable to "pinch off" the extra cytoplasmic material into two daughter cells because the formation of a division furrow depends on the ability to synthesize new cell wall.5- The cell wall is shed entirely, forming a spheroplast, which is extremely vulnerable relative to the original cell.
  • The loss of the cell wall also causes the cell to lose control over its shape, so even if the original bacterium were rod-shaped, the sphereoplast is generally spherical.
  • Finally, the fact that the cell has now doubled much of its genetic and metabolic material further disrupts homeostasis, which usually leads to the cell's death.

• Making Memory B Cells

  • Memory B cells are a B cell sub-type that are formed following primary infection.
  • Memory B cells are a B cell sub-type that are formed following a primary infection .
  • Most of them differentiate into the plasma cells, also called effector B cells (which produce the antibodies) and clear away with the resolution of infection.
  • Each time these cells are induced to proliferate due to an infection, the genetic region coding for the paratope undergoes spontaneous mutations with a frequency of about 1 in every 1600 cell divisions.
  • The fact that all the cells of a single clone elaborate one (and only one) paratope, and that the memory cells survive for long periods, is what imparts a memory to the immune response.