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Grow And Divide:
Not all cells divide into two daughter cells. For example, the alga Chlamydomonas divides into eight daughter cells. Some other algae and fungi divide into hundreds of daughter cells.Nonceffular, or Syncitial, Growth. Some kinds of alls can grow extensively without cell division. One group of microorganisms, the Mycetozoa, east as huge ameboid protoplasmic masses called plasmodia, which contain thousands of nuclei without cell membranes. Occasionally, fragments separate from the plasmodium, and these fragments can grow in size and their nuclei can divide. These noncellular multinuclear organisms or tissues are referred to as syncytial.When normal animal cells are cultivated on glass surfaces overlaid by a liquid nutrient medium, they grow and divide. The daughter cells can move away from each other by ameboid motion. When the cells are so numerous that their surfaces come into frequent contact, the population immediately stops growing. Experiments have shown that the contact between cells is responsible for the growth stoppage, a phenomenon described as contact inhibition.
Attention was recently focused on a special group of bacteria, the Bdellovibrio, that attack , other bacteria. These parasites enzymatically [drill a hole in the rigid Wall of the host bac- iterium, crawl into the space between the wall [and the cell membrane, and grow and divide ' at the expense of material absorbed from the protoplasm of the host cell.
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