Paramecium bursaria organelles (Micronucleus and Macronucleus identified) скачать в хорошем качестве

Paramecium bursaria organelles (Micronucleus and Macronucleus identified)

Just a quick "information video, pointing out the two kinds of nuclei found in ciliates. I've labelled a couple of other organelles, as well. Ciliates are unusual in having two types of cell nucleus. The large "macronucleus" regulates the daily operations of the cell. The smaller "micronucleus" -- the "germline" nucleus -- is used in reproduction to carry the genetic code of the organism to future generations. Reproduction is always asexual, by binary fission, and sometimes preceded by a sexual phenomenon called "conjugation. The macronuclei can take many shapes, depending on the species of the ciliate. It might be long and wormlike, small and spherical, oval, or strung out like a string of beads. Some ciliates have many macronuclei, but Paramecium has only one, usually a large oval located near the centre of the cell. Ciliate micronuclei are relatively small, like little beads or ovals, usually nestled up against the macronucleus. Some ciliate species have just one, others may have dozens. In Paramecium bursaria,the number of micronuclei varies, but there is typically just one. This one is easy to see, because the Paramecium is unusually transparent, with very little symbiotic green algae in its cytoplasm.