Test: Kingdom Protista- 2 - NEET MCQ

The symbiotic association between fungi and higher plants is known as
mycorrhiza whereas lichen is an example of symbiotic association between algae and fungi.

• Euglenoids have a protein rich layer called pellicle which makes their body flexible.
• Euglenoids have two flagella that help in their movement.
• Euglena changes its body shape during its movement and this phenomenon called as metaboly is possible due to pellicle.

lichens, sexual reproduction belongs to Fungal partner only.

Lichens exhibit the symbiotic association between algae and fungi. In this plant, algae is the photosynthetic partner involved in food preparation and the fungal partner increases the surface area for the absorption of water and minerals. Also, the fungal partner is involved in sexual reproduction with the help of reproductive structures called apothecia.

Five-kingdom classification is based on the criteria, except Fruiting bodies.

A fruiting body is the multicellular structure of an organism on which spore-producing structures, such as basidia or asci, are born. Fruiting body may also refer to: Fruiting body (bacteria), the aggregation of myxobacterial cells when nutrients are scarce. Fruiting body (slime mold), the sorophore and sorus.

The protists have Membrane-bound nucleoproteins lying embedded in the cytoplasm.

Protists are eukaryotic organisms. They have a well-developed nucleus They also contain many cell organelles that are membrane-bound. Membrane-bound nucleoproteins are also present in them. Most of them are unicellular organisms. 

Dinoflagellates are the bioluminiscent algae. They have pigment luciferin, which is acted upon by the enzyme luciferase causing production of light without any heat, thus the name fire algae. The enzymatic reaction of pigment produces light; pigment itself does not impart the fire-like appearance.

• Slime moulds are considered to be fungus like protists since they grow in moulds and reproduce using spores.
• But there are many differences between Slime moulds and fungi.
• Unlike fungi, slime moulds lack chitin in their cell wall and are mobile.

Diatoms are phytoplanktons that float on water surface. They are the primary photosynthetic producers in marine food chains and store their food as oil or lipids and polysaccharide leucosine. 

Diatomaceous earth is primarily composed of silica embedded in the cell walls of diatoms. The indestructible nature of these walls, due to silica, leads to the accumulation of diatomaceous earth over billions of years.

Protozoans are a diverse group of eukaryotes that are primarily unicellular. They are called acellular orgasnisms because their cells do not have a fix shape and they often change their shapes as in case of amoeba through pseudopodia.

Slime molds were once considered fungi, but unlike fungi, they can move, and their cell membranes are made of different stuff. The dictyostelids are another group formerly classified among the fungi. They are slime molds that feed as unicellular amoebae, but aggregate into a reproductive stalk and sporangium  under certain conditions. Cells of the reproductive stalk, as well as the spores formed at the apex, possess a cellulose cell wall. The spore wall has been shown to possess three layers, the middle of which is composed primarily of cellulose, and the innermost is sensitive to cellulase and pronase.

Chrysophytes They have a cell wall made of two halves.

In Chrysophytes, cell walls are formed by the two things overlapping shells. This fit together in a small box. The walls are embedded with silica and thus walls are indestructible.

• Like Slime moulds, Protozoans also don’t contain cell wall.
• Slime moulds feed on bacteria, yeast and fungi and have amoeba like food ingestion.
• The pigments in Euglena are identical to that of higher plants.
• Slime moulds reproduce either by forming an aggregate called plasmodium or by spore formation.

In diatoms call wall is arranged in the form of lid like soap bar. So it's cell wall has divided in two parts.

Cells of Diatoms are surrounded by the cell wall, frustules, which has silica deposits. Shells of diatoms are highly resistant to decomposition due to the presence of silica and are deposited in ocean beds leading to the formation of the diatomaceous earth. Diatomaceous earth is used as a filtration aid, mild abrasive in products including metal polishes and toothpaste, mechanical insecticide, absorbent for liquids, matting agent for coatings, a stabilizing component of dynamite and a thermal insulator as it is a bad conductor of heat.

Penicillin class drugs work by indirectly bursting bacterial cell walls. They do this by acting directly on the cell wall, which plays an essential structural role in bacterial cells. but, Mycoplasma does not have a cell wall. Thus, Penicillin can not act on the mycoplasma. So, mycoplasma is not sensitive to penicillin.

Brown algae (Pheophyceae) are characterized by the presence of motile reproductive phase with two lateral flagella. Green algae are characterized by unicellular flagellated cells or microscopic colonies of flagellated or non-flagellated cells and reproduce by zoospores.

• Pseudopodia help amoeboids in both locomotion and ingestion of food.
• Pseudopodia are temporary extensions in amoeba that help them to move to as well as intake food by surrounding it with temporary extensions.

Diatoms are phytoplankton that floats on the water surface. They are the primary photosynthetic producers in marine food chains and store their food as lipids and polysaccharide leucosine. Since lipids have a lesser density than that of seawater, diatoms store oil or lipids in their vacuoles to maintain the buoyancy and thereby to float on water.

Cell of Diatoms are surrounded by cell wall having two parts or frustules; frustules make two overlapping halves (the epitheca and the hypotheca). Presence of numerous tiny pores in frustules connects the protoplast of the cell with the outside environment. The pectin substance of cell wall is richly impregnated with silica, which creates patterns of minute perforations and striations. Around 90 percent of diatomaceous cell wall is silica. Shells of diatoms are highly resistant to decomposition due to presence of silica and are deposited in ocean beds leading to formation of porous diatomaceous earth. It serves as porous acoustic material i.e. a solid material with cavities/channels to facilitate the entry of sound waves and their absorption with very little reflection. This makes option B correct. Dinoflagellates have armoured cellulosic cell wall while euglenoids lack cell wall but have pellicle which is a semi-rigid proteinaceous structure. Zooflagellates are protozoans that lack cell wall.

• Movement in paramecium is due to hair like structures called cilia that grows on its body.
• Paramoecium can move actively due to the presence of thousands of cilia.
• Cilia performs rhythmic movement in order to steer food containing water into the gullet.

Diatoms produced by a special type of spores which r know as auxospores. Dinoflagellates and euglenoids produce by binary fission, spore formation does not take place.

During unfavourable conditions, the vegetative cells of haploid protists become encysted with resistant outer covering in which cell metabolism is more or less completely shut down. It provides resistance to desiccation. These dormant structures resume metabolic activity and germinate asexually to form new organism upon arrival of favourable growth conditions. For example, some chrysophytes. 

Binary fission is also asexual mode of reproduction in protists wherein replication of chromosome is followed by inward growth of cytoplasmic membrane and the cell wall splitting from the outside toward the centre to divide the cell into two daughter cells. 

Gametic meiosis refers to meiosis in diploid gamete mother cells to produce haploid gametes which will then fuse to restore the vegetative diploid phase. Therefore, it occurs in diploid protists. For example, diatoms, metazoans. 

Zygotic meiosis occurs directly after fertilization, resulting in production of all haploid individuals, the diploid phase is represented by zygote only while the vegetative phase is haploid. For example, sporozoans and dinoflagellates.

Resembling an amoeba specifically in moving or changing in shape by means of protoplasmic flow. Amoeboid movement is the most common mode of locomotion in eukaryotic cells. It is a crawling-like type of movement accomplished by protrusion of cytoplasm of the cell involving the formation of pseudopodia ("false feet") and posterior uropods.

Unicellular organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. Prokaryotes include bacteria and archaea. Many eukaryotes are multicellular, but the group includes the protozoa, unicellular algae, and unicellular fungi.