Protista - class-X

The five kingdom classification was proposed by R.H. Whittaker in 1969. The five kingdoms were formed on the basis of characteristics such as cell structure, mode of nutrition, the source of nutrition and body organization. It includes Kingdom Monera,  Protista, Fungi, Plantae, and Animalia. According to Whittaker's 5 kingdom classification, unicellular eukaryotes belong to kingdom Protista. Amoeba and euglena are unicellular eukaryotic organisms so they belong to kingdom Protista.

Contractile vacuoles are membrane-bound cellular organelle found in many microorganisms. These periodically expand and get filled with water and contract, expelling the contents to the exterior of the cell.

• Kingdom Protista includes Eukaryotes can be unicellular or multicellular. they produce sexually or asexually  eg. Plasmodium( cause malaria) , Ameoba.
  
• Autotrophic organism creat their own food by fixing carbon .  kingdom Plantae includes all unicellular or multicellular autotrophic organism.
  

A protist is any eukaryotic organism that is not an animal, plant or fungus. The protists do not form a natural group, or clade since they exclude certain eukaryotes; but, like algae or invertebrates, they are often grouped together for convenience. 

Diatoms are protistand in which the cell walls form two thin overlapping shells, which fit together as in a soap box. The walls are embedded with silica. 

Protists have a membrane-enclosed nucleus and membrane-enclosed organelles. This nucleus is embedded in the cytoplasm. They may be single or many in number and the nucleus has a membrane covering called the nuclear envelope with pores over it. 

Cytoplasmic inheritance, also known as extranuclear inheritance is actually the transmission of genes that occurs outside the nucleus. Kappa particles show cytoplasmic inheritance. Here phenotype not only depends on the cytoplasm but also on the genetic material of the nucleus.

The correct answer is A.

Contractile vacuoles are used by freshwater protozoa to expel excess water. Since species X had one in fresh water but lost it in sea water, it is adapted to fresh water. Species Y did not have one in fresh water, suggesting it is already adapted to marine environments.

Monerans are prokaryotic organisms. They lack a well-developed nucleus and cell organelles. But, on the contrary, protozoa have a well-developed nucleus and are eukaryotic organisms. Bacteria have a cell wall made of cellulose and chitin. Bacteria lack a cell membrane. 

An organism in it's dormant stage is called a cyst. In these conditions, an organism is inactive and does not perform any daily activities. Thus, they help the organisms survive in unfavourable conditions.

Lophomonas are the protists that can live in a symbiotic relationship or as a parasite in the body of their host. The hosts are arthropods, which could be termites, cockroaches in which lophomonas lives in their digestive system or intestinal tracts.

The correct answer is B.

• The simple protists were similar to bacteria but they gradually evolved as eukaryotes wherein each cell is having a nucleus. 
• They are not an animal, plant or fungus but they may be closely related to plants. 
• They may survive alone or may group as per the convenience.
• The correct answer is D. 

• Zootermopsis, the pine woods termite, contains vast numbers of the wood engulfing symbiont Trichonympha, along with a number of other species, such as the primitive flagellate, Streblomastix and Trichomonas, a genus commonly found in warm, moist interiors of virtual all species of animals. 
• Trichonympha along with these huge cells are bacteria residing in the termite gut assist in breaking down the cellulose. Hence the correct option is D.

Water collecting canals around the contractile vacuole are called Radiating canals The contractile vacuole is the part that contracts and forces extra water out of the cell. The radiating canals are the paths to the contractile vacuole. In Paramecium, these are two contractile vacuoles while one in Amoeba.

Entamoeba histolytica secretes proteolytic enzyme called Histolysin.

• The movement of protists is affected by various surrounding factors,  certain protists move by special locomotive structures. 
• Ciliated cells and flagellated cells move faster than others, but the flagellated cells are able to move as fast as 2.0 mm/sec.
• The correct answer is B.

Protista are eukaryotic organism. They have well defined membrane bound nucleus, which encloses genetic material and membrane bound cell organelle in cytoplasm.

Enterobius vermicularis (pinworm) is a nematode, which is a type of multicellular parasitic worm, not a single-celled protozoan protist.

Elephantiasis is caused by parasitic filarial worms (nematodes), whereas the other diseases listed are caused by protozoan protists.

Schizogeny is the method of reproduction in which production of a sexual individual from an asexual form usually by fission.

Protists exhibit diverse life cycles, including both zygotic meiosis (common in many algae and fungi-like protists) and gametic meiosis (common in many ciliates and animals).

Kingdom Protista includes diverse eukaryotic organisms that are primarily unicellular, such as diatoms, protozoans, and unicellular algae. Monera consists of prokaryotes, while Fungi and Plantae are generally multicellular (with exceptions like yeast).

Unicellularity is a fundamental characteristic of organisms in Kingdom Monera (bacteria) and Kingdom Protista. Cyanobacteria are a phylum within the Kingdom Monera, so all listed groups exhibit unicellularity.

Protists are eukaryotic organisms, meaning they possess membrane-bound organelles and a defined nucleus. The statement that they are prokaryotic is incorrect, as prokaryotes belong to the Kingdom Monera.

Noctiluca scintillans belongs to class Flagellata of phylum Protozoa. It is the most common cause of bioluminescence in the ocean. Because of this, it is also called sea sparkle. It produces light throughout the cytoplasm by luciferin- luciferase reaction.

Kingdom Protista includes various groups such as Amoeba (sarcodines), Paramecium (ciliates), and dinoflagellates/diatoms (algae). Yeast is a fungus, Hydra is an animal, and Mushrooms are fungi.

Dinoflagellates are marine protists known for their rapid spinning movement. Certain species, such as those causing red tides, produce potent toxins that can kill marine life, including fish.

Proterospongia is a colonial flagellate. It is considered a connecting link between protists and sponges because it exists as a colony of choanocyte-like cells, which are the characteristic cell type of sponges.

Diatoms are the organisms belonging to Chrysophytes of kingdom Protista. Diatoms occur in all aquatic and moist terrestrial habitats. They may be free floating or bottom dwellers. The free-floating forms remain suspended on the surface of water by mucilage secretion and presence of lightweight lipids. The cell wall is made of silica which is known as frustule. The frustule is made up of two valves, epitheca, and hypotheca. The two valves fit together like a soapbox. They produce auxospores. Auxospore is a rejuvenescent cell which is a zygote grown in size.

When a freshwater protozoan is placed in marine water, the contractile vacuoles disappear. The function of contractile vacuole is to remove the excess water outside by the process of osmoregulation. In marine water, it is necessary to retain the water inside the body instead of out expelling it out. If contractile vacuoles will not disappear, the cell will get dehydrated.

• Euglena is a protist that can both eat food and can photosynthesize. When acting as a heterotroph, the Euglena surrounds a particle of food and consumes it by phagocytosis. When acting as an autotroph, the Euglena utilizes chloroplasts to produce sugars by photosynthesis that's why it is said to be a plant-animal.
• Hence A Protistan which is commonly called plant-animal is Euglena.
• So, the correct answer is 'Euglena'.

(A)Protista are simple eukaryotic organisms that cannot be classified as plant, animal or fungus. They are mostly unicellular, but some are multicellular. They are first originated.

A protist is any eukaryotic organism (one with cells containing a nucleus) that is not an animal, plant or fungus. The protists do not form a natural group, or clade, since they exclude certain eukaryotes; but, like algae or invertebrates, they are often grouped together for convenience. In some systems of biological classification, such as the popular five-kingdom scheme proposed by Robert Whittaker in 1969, the protists make up a kingdom called Protista, composed of "organisms which are unicellular or unicellular-colonial and which form no tissues".

Rhizobium : Bacteria :: Diatoms : Algae

A.Diatoms – cell wall is made up of silica and cellulose.

B.Dinoflagellates – cell wall is made up of cellulose and is present in the form of plates.

D.Euglenoids – cell wall is absent.

So, the correct option is ‘Dinoflagellates’.

All single-celled eukaryotes are placed under Protista, but the boundaries of this kingdom are not well defined. Members of Protista are primarily aquatic. This kingdom forms a link with the others dealing with plants, animals, and fungi. Being eukaryotes, the protistan cell body contains a well-defined nucleus and other membrane-bound organelles.

Protists are eukaryotic organisms that are mostly unicellular in nature. They can be mainly classified into three main categories:-

• Animal-like protists, which are heterotrophs and has the ability to move.
  
  
• Plant-like protists- that are autotrophs and can photosynthesize.
  
  
• Fungi like protist- that are heterotroph and possess a cell with the cell wall.
  
  
• Kingdom Plantae includes mainly multicellular, eukaryotic organisms that have the ability to do photosynthesis. Kingdom Monera composed of organisms that are prokaryotic and unicellular. 
  
  
• Kingdom Animalia includes animals which are eukaryotic multicellular. They do not perform photosynthesis.

Kidneys seem to have evolved in primitive freshwater vertebrates to help them expel the excess water that continuously entered the body by osmosis. Later, kidneys also acquired the function of removing the waste materials from body.

The kidneys in vertebrates are bean-shaped organs that remove excess organic molecules from the blood, and waste products of metabolism. In protozoans, the contractile vacuole does the function of the kidneys of vertebrates an expels the excess water from the system.

Therefore, the correct answer is option c.

Chrysophyta, Phaeophyta, Rhodophyta are the group which contains multicellular organisms.

The contractile vacuole is a structure found in many marine organisms. It functions as an organelle to eliminate the excess water which may have stored in the cell because of osmotic conditions.