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

List the four objectives of counselling a diabetic patient, Q. List the fou...

Q. List the four objectives of counselling a diabetic patient? Objectives of Diabetes Counselling 1. Facilitating decision to start treatment and change life style 2.

Phylum porifera, harmful and beneficial usesa of phylum porifera

harmful and beneficial usesa of phylum porifera

Define changes in food due to concentration process, Define Changes in Food...

Define Changes in Food due to Concentration Process? Obviously concentration that exposes food to 100°C or higher temperatures for prolonged periods can cause major changes in

Trypsin, Trypsin Trypsin is secreted by the pancreas in an inactive fo...

Trypsin Trypsin is secreted by the pancreas in an inactive form trypsinogen. It is activated by enterokinase secreted by the glands in the intestinal wall. As trypsin is forme

Explain about selection of healing abutment, Selection of healing abutment ...

Selection of healing abutment It is done depending upon the tissue thickness. Tissue thickness can be measured similar to ridge mapping or sounding procedure, wherein after an

Explain tropical rain forests in biomes, Explain Tropical Rain Forests in b...

Explain Tropical Rain Forests in biomes? You probably are well aware of the danger that the world's rain forests are facing in terms of extinction! There are huge numbers of sp

Points, What is the classification of protozoa with examples

What is the classification of protozoa with examples

Destruction of microorganisms, Q. Destruction of microorganisms? Ans. ...

Q. Destruction of microorganisms? Ans. Destruction or control of growth of microorganisms is the basis of food preservation. To 'preserve' actually means fro keep safe, r

Define briefly about the copper, Define Briefly about the Copper? As ea...

Define Briefly about the Copper? As early as the times of Hippocrates, copper compounds were used to treat various diseases. However, in the 20" century, it was noticed that an

Hetero trophic mode of nutrition, what is heterotroophic mode of nutrition?...

what is heterotroophic mode of nutrition?give some information about heterotrophic mode of nutrition?

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