Ciliated protozoan, Biology

Assignment Help:

Ciliated Protozoan

Ciliates form the largest and the most homogenous group of protozoans. They are placed under one phylum Ciliophora and evidence indicates that its members share a common evolutionary history. There are more than 7200 species found in fresh and marine waters and the water film of soil. About one third of ciliates are ecto and endoparasites or commensals. The classic example of this phylum is the slipper shaped Paramecium. Other well known examples are Vorticella, Stentor, Didinium, Balantidium.

317_Ciliated Protozoan.png

Figure: Various ciliates. Vorlieella and Stentor sessile ciliates, Stentor can also release itself and swim about. Didinium a raptoral ciliate Tetrahymena, Acineta with bunches of tentacles.


All ciliates possess cilia for locomotion and for suspension feeding. Another (Organization) distinguishing feature is the presence of kinetosomes (ciliary basal body) and an associated complex anchorage system of fibrils connecting the kinetosomes in longitudinal rows. All of these make the subsurface ciliature or infraciliary system. Most ciliates have a mouth or cytostome and feed by sweeping particle laden water into the mouth. The cytostome and cytopharynx open into the food vacuole and undigested remains are expelled through a fixed spot. Another characteristic feature is the presence of 2 types of nuclei. One large macronucleus and one or more small micronuclei. The macronucleus is called the vegetative nucleus as it regulates the normal metabolic processes of the organism for mitotic division and for control of cellular differentiation.

It is required for protein synthesis. The amount of DNA that macronucleus contains is much more than what is present in micronucleus because of duplications following the formation of macronucleus from the micronucleus. The micronucleus on the other hand is small and rounded. It is diploid and more than one may be present, with little RNA. The micronucleus contains the genetic material responsible for genetic exchange during sexual reproduction and also for reforming the macronucleus. Ciliates reproduce asexually by transverse fission and sexually through conjugation which involves the exchange and fusion of micronuclei at the region of contact.


Related Discussions:- Ciliated protozoan

Ovary is half-inferior in which flower, Ovary is half-inferior in the flowe...

Ovary is half-inferior in the flowers of : 1. Guava 2. Plum 3. Brinjal 4. Cucumber Plum is the flower in which ovary is half - inferior

Synapse - nervous system, Synapse   Nervous System Structural feature ...

Synapse   Nervous System Structural feature of unique importance in the nervous tissue is the synapse. A synapse is the anatomical site at which axon terminal processes of one

What are cytokines, What are Cytokines? Cytokines are polypeptides, whi...

What are Cytokines? Cytokines are polypeptides, which influence the proliferation, differentiation, metabolism and activation of cells. There are three areas in cancer that hav

Tissue culture, Tissue culture The ability of a plant cell to give r...

Tissue culture The ability of a plant cell to give rise to a whole plant is called totipotency. The culture of a cell or a tissue in a suitable medium to produce new plan

Single pair of alleles, Give three examples of human disorders which are ca...

Give three examples of human disorders which are caused by the action of a single pair of alleles. In every case say whether the harmful allele is dominant or recessive to the non-

Avian tuberculosis, A v i a n tuberculosis Tuberculosis in poultry ...

A v i a n tuberculosis Tuberculosis in poultry has not remained a big threat in list of diseases due to commercialization of poultry business. It is a contagious chronic di

Explain about the magnesium - macro minerals, Explain about the Magnesium -...

Explain about the Magnesium - macro minerals? Magnesium (Mg) ranks fourth in overall abundance in body among the cations. It is also the least abundant among macro minerals, th

Formation of cocoon in earthworm, Formation of cocoon in earthworm: I...

Formation of cocoon in earthworm: In earthworm segments from 14 to 17 are swollen. Skin on these segments is thick and glandular. This is called clitellum. When ovaries ma

Explain conventional factors for cad, Explain Conventional Factors ? Sm...

Explain Conventional Factors ? Smoking, Hypertension, diabetes mellitus, obesity, hypercholesterolemia, and reduced physical activity are considered as conventional risk factor

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd