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

Determine the term - chlorine, Determine the term - Chlorine   The appl...

Determine the term - Chlorine   The application of chlorides results in leaves of greater spread, a lighter green colour and with a smoother surface. However, the combustibilit

Major renal processes that combined produce urine, Q. What are the three ma...

Q. What are the three major renal processes that combined produce urine? Urine is made by the occurrence of three processes in the nephron that are tubular resorption, glomerul

Define objectives to know about methods of food processing, Define Objectiv...

Define Objectives to know about methods of food processing? After studying this unit, you will be able to: Enumerate the different methods of food processing Enlist

Budding, What processes occur during the budding of yeast?

What processes occur during the budding of yeast?

Stress - responses of plants to stress, Stress - Responses of Plants to Str...

Stress - Responses of Plants to Stress Let us recall what happens within the natural communities occupying the same habitat. The relative location of two plants may place them

What is the tertiary structure of a protein, What is the tertiary structure...

What is the tertiary structure of a protein? What are the main kinds of tertiary structure? The tertiary protein structure is a spatial conformation additional to the secondary

Define determinants of food security - food availability, Define Determinan...

Define Determinants of Food Security - Food Availability? It depends on the quantum and quality of crops, livestock, fishery and other food sources, as well as commercial impor

What is autophagic intracellular digestion, What is autophagic intracellula...

What is autophagic intracellular digestion? Why is this type of intracellular digestion intensified in an organism undergoing starvation? Autophagic intracellular digestion is

Poverty and malnutrition, Poverty and Malnutrition Poverty and malnutr...

Poverty and Malnutrition Poverty and malnutrition are closely related. As noted before, many elementary aspects of being poor like hunger, inadequate health care, unhygienic l

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