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B. Pinocytosis:
Some take in food by way of phagocytosis, engulfing organic particles with pseudopodia (as amoebae do), or taking in meals via a specialized mouth-like aperture known as a cytostome. some protozoans soak up meals by using osmotrophy, absorbing dissolved nutrients thru their cellular membranes pinocytosis or cell-consuming has additionally been suggested in some protozoa like Amoeba proteus, and additionally in positive flagellates and ciliates. it’s far associated with the ingestion of liquid food through invagination of the general frame floor. it is able to occur at any part of the body; during pinocytosis, some pinocytic channels are fashioned from the outer body floor deep into the body.the inner ends of those channels’ include pinocytic vesicles or pinosomes which get separated after engulfing liquid food thru the channels. The separated pinosomes come to be the meals vacuoles. this method is triggered in presence of positive salts and some proteins.
Fig2.2.Pinocytosis

C. Autotrophic Or Holophytic Nutrition:
Protozoa with chlorophyll or a few allied pigment can also manufacture complex organic meals, like the ones of inexperienced vegetation, from simple inorganic substances, For example, euglena, noctiluca. regularly there may be protein bodies known as pyrenoids that are the base of photosynthesis.A few protozoa haven’t any of chromatophores but they have got chlorophyll-bearing algae zooxantliellae or zoochldrellae which make organic food for the host with the aid of photosynthesis, For example, Stentor, thalassicola, Paramecium bursaria. nitrates or ammonium compounds are sufficient because the source of nitrogen for autotrophic forms.
D. Saprozoic Nutrients:
Some protozoa take in complex natural materials in solution through the frame floor by means of osmosis referred to as osmotrophy,and these are known as saprozoic. Saprozoic paperwork want ammonium salts, amino acids, or peptones for his or her dietary requirements. Decaying of animals and flowers in water bureaucracy proteins and carbohydrates.
The saprozoic protozoa are generally parasites like monocystis. However a few parasites, like Entamoeba histolytica and balantidium coli feeding also absorb dissolved organic materials by their standard body floor. However, some colourless flagellates like chilomonas, polytoma and species of euglena soak up nutrients from their surrounding environment thru their fashionable body floor
E. Parasitic Nutrition:
The parasitic protozoans use a wide form of feeding techniques, and some may additionally alternate strategies of feeding in different stages of their life cycle. For example, the malaria parasite Plasmodium feeds by using pinocytosis for the duration of its immature trophozoite stage of lifestyles (ring segment), but develops a dedicated feeding organelle (cytostome) as it matures within a bunch’s red blood cell.Accordingly, the parasites can be grouped into two categories on the way of food and their mode of feeding:
(I) Meals-Robbers:
Those feeding upon the undigested or digested foodstuffs of their hosts are known as meals-robbers, And with some ciliate parasites like nyctotherus, balantidium. those parasites feed holozoically on stable food debris, few others like opalina feed upon the liquid food via the osmosis through their fashionable body surfaces.These are generally non-pathogenic to their hosts.
(Ii) Pathogenic:
Some protozoan parasites inflicting harm to their hosts, normally feed upon the dwelling tissues of the host.Liquid food take in by their widespread body surface, e.g., trypanosoma, plasmodium, and so on.
F. Coprozoic Nutrients:
Some loose-living protozoans are in habit of feeding on the faecal matters of the opposite organisms like Clamydophrys and Dimastigamoeba.

G. Mixotrophic Nutrients:
They might also stay as mixotrophs, supplementing a heterotrophic weight-reduction plan with the some form of autotrophy.Shape of some protozoa close institutions with symbiotic photosynthetic algae, which stay and grow within the membranes of the bigger cell and offer nutrients to their host. Others practice kleptoplasty, stealing chloroplasts from prey organisms and maintaining them inside their own cell bodies as they retain to produce nutrients through photosynthesis. The ciliate mesodinium rubrum keeps functioning plastids from the cryptophyte algae on which it feeds. Thus, in turn, can be passed alongside to dinoflagellates of the genus dinophysis , which prey on mesodinium rubrum but keep the enslaved plastids for themselves inside dinophysis, these plastids can retain to characteristic for months.Other protozoa nourish themselves with the aid of more than one method at the equal time or at one of a kind instances because of change in environment. that is known as mixotrophic vitamins, e.g., euglena gracilis and also peranema are each saprozoic and autotrophic in their nutrients, and a few flagellates are both autorophic and zootrophic.however, protozoa which feed on a large variety of meals organisms are called euryphagous, and people which feed most effective on a few kinds of meals are stenophagous.
On the premise of the nature of meals and feeding mechanism in protozoa, they’re placed in the following corporations:
(a) macrophagous feeders are those which feed on massive pieces of meals (amoeba),
(b) microphagous feeders are the ones which feed on very small debris, they not often prevent feeding and their meals is drawn in with a modern-day of water (paramecium).
(c) fluid feeders are saprozoic and parasitic protozoa which take in liquid meals through their surface (monocystis).
2.2.Breathing In Protozoa:
For the process of respiration protozoa do not have any organellae. The restricting permeable membrane acts as a respiration floor. The unfastened molecular oxygen from the encircling media enters into the frame by the diffusion. Presence of a cytochrome device has been also verified in protozoa.
Protozoa thet stay as parasites in the digestive tube of better animals do now not get molecular oxygen in free nation however get it via decomposing complicated oxygen bearing substances present within the body of the host.
Anaerobic protozoa include trypanosoma gambiense of vertebrate blood. while histomonas meleagridis, a flagellate in the intestine of fowl can grow in presence of air in addition to without it and is a ‘facultative aerobe’
Fig2.3.Respiration in protozoa

2.3Excretion In Protozoa:
Water, carbon dioxide and nitrogenous compounds that are waste materials and stay in soluble form. These are surpassed out of the frame by means of diffusion or by way of the contractile vacuoles surrounding water is hypertonic to freshwater amoeba.
For example
So, water constantly enters through the mobile surface in the frame of amoeba. This excess water interferes with the body capabilities and is removed via the discharge of contractile vacuole. Marine or parasitic protozoa live in isotonic media and they no longer have contractile vacuoles.
A minor quantity of carbon dioxide is diffused out via the cellular floor rest of the carbon dioxide and ammonia which remain in soluble kingdom are thrown out of the frame by the contractile vacuoles.
Insoluble materials inside the shape of crystals of calcium phosphate (recorded in amoeba proteus) ureate, carbonate, oxalate and grains (haemozomin in haemosporidians) are frequently encountered. These substances are considered as catabolic merchandise. The manner they’re extruded remains in statement level in most protozoa, excretion of nitrogen takes place within the form of ammonia and loose amnio acid.

Fig2.4.Excretion in protozoa

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