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

Define nutritional support management for chemotherapy, Define Nutritional ...

Define Nutritional Support Management for chemotherapy? Antiemetics are used in the treatment of chemotherapy induced nausea and vomiting. Antiemetics become absolutely necessa

Process of regeneration in planarians, Process of Regeneration in Planarian...

Process of Regeneration in Planarians Regeneration in planarians has been broadly studied and considerable information regarding this phenomenon is now available. Let us see w

Electroconvulsive therapy, ELECTROCONVULSIVE THERAPY: 1)  ConceptlMean...

ELECTROCONVULSIVE THERAPY: 1)  ConceptlMeaning of  Electroconvulsive Therapy  (ECT) Electroconvulsive Therapy (ECT) is a painless form of  electric therapy. It is called as ph

Define promoting food security to control under nutrition, Define Promoting...

Define Promoting food security to control under nutrition? Public distribution of food grains through a network of ration shops, particularly to reach the population below the

Digestive system - buccal cavity, BUCCAL CAVITY - Situated between u...

BUCCAL CAVITY - Situated between upper & lower jaw. It is lined by stratified squamous epithelium. Separated from nasal chamber by palate. Palate forms roof of buccal cav

Coagulation, which is the last enzyme in the thrombotic system?

which is the last enzyme in the thrombotic system?

Plastids, Plastids The term plastid first used by Haeckel (1865). ...

Plastids The term plastid first used by Haeckel (1865). These are present in plants and few protists (Euglena). On the basis of function plastids are of three types

Crossing over, is crossing over of chromosomes is a method?

is crossing over of chromosomes is a method?

What in genetics is hybridization, What in Genetics is hybridization? H...

What in Genetics is hybridization? Hybridization in Genetics is the crossing of individuals from "pure" and dissimilar lineages in relation to a given trait, i.e., the crossing

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