Kingdom Protista Features Practice Questions
20 free Kingdom Protista Features practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which of the following is the primary habitat of the majority of organisms belonging to Kingdom Protista?
- A Terrestrial
- B Aquatic
- C Arid
- D Endoparasitic
Correct answer: Aquatic
Members of Protista are primarily aquatic, inhabiting freshwater ponds, marine environments, and moist soil. They form a vital link between unicellular prokaryotes and multicellular eukaryotes.
The cell wall of diatoms is indestructible primarily due to the deposition of:
- A Starch
- B Chitin
- C Silica
- D Pectin
Correct answer: Silica
Diatoms have cell walls embedded with silica, which form two thin overlapping shells that fit together like a soap box. This siliceous composition makes the walls extremely durable, leading to the accumulation of 'diatomaceous earth' over geological time.
Which group of protists is known for causing 'red tides' in the ocean, making the water appear red?
- A Amoeboid protozoans
- B Dinoflagellates
- C Euglenoids
- D Slime moulds
Correct answer: Dinoflagellates
Red dinoflagellates such as Gonyaulax undergo rapid multiplication that makes the sea appear red. These organisms can also release toxins that are harmful to marine fish and other animals.
Euglenoids are considered a link between plants and animals because:
- A They have a cell wall made of cellulose but are heterotrophic
- B They photosynthesize in sunlight but switch to heterotrophic feeding in the dark
- C They possess cilia for movement but lack a nucleus
- D They reproduce exclusively by spore formation and lack any sexual stage
Correct answer: They photosynthesize in sunlight but switch to heterotrophic feeding in the dark
Euglenoids like Euglena are mixotrophic: they perform photosynthesis when light is available but consume organic matter when deprived of sunlight. Their photosynthetic pigments are identical to those found in higher plants.
In Euglenoids, the flexible body is due to a protein-rich layer called:
- A Capsule
- B Pellicle
- C Frustule
- D Plasmodium
Correct answer: Pellicle
Instead of a rigid cell wall, Euglenoids have a protein-rich layer called a pellicle. This structure is located just inside the plasma membrane and makes their body flexible.
Under suitable conditions, slime moulds form an aggregation called:
- A Sporocarp
- B Pseudopodium
- C Plasmodium
- D Cyst
Correct answer: Plasmodium
During favorable conditions, saprophytic protists known as slime moulds aggregate to form a structure called plasmodium. This mass may grow and spread over several feet.
Which organism is responsible for causing Sleeping Sickness in humans?
- A Entamoeba histolytica
- B Plasmodium vivax
- C Trypanosoma
- D Paramecium
Correct answer: Trypanosoma
Trypanosoma is a flagellated protozoan that is an endoparasite. It causes African Sleeping Sickness, which is transmitted by the tsetse fly.
Ciliated protozoans like Paramecium possess a cavity that opens to the outside of the cell surface called the:
- A Pulsatile vacuole
- B Oral gullet
- C Anal pore
- D Food vacuole
Correct answer: Oral gullet
Paramecium has a permanent funnel-shaped oral gullet that opens to the exterior. The coordinated movement of cilia drives water carrying food particles into this cavity, which then passes deeper into the cell.
Which of the following groups includes 'diatoms' and 'golden algae'?
- A Dinoflagellates
- B Chrysophytes
- C Protozoans
- D Euglenoids
Correct answer: Chrysophytes
Chrysophytes include diatoms and golden algae. They are mostly photosynthetic and are the chief 'producers' in the oceans, playing a vital role in aquatic food chains.
Sporozoans are characterized by:
- A Possessing flagella as the primary means of locomotion in all stages
- B The presence of cilia for feeding and movement
- C Possessing a spore-like infectious stage in their life cycle
- D Being exclusively saprophytic in all environments
Correct answer: Possessing a spore-like infectious stage in their life cycle
Sporozoans, such as Plasmodium (the malarial parasite), are characterized by having an infectious spore-like stage in their life cycle. All sporozoans are parasitic and lack specialized locomotory organelles in the adult stage.
During unfavorable conditions, the plasmodium of slime moulds differentiates and forms:
- A Differentiated sex cells
- B Fruiting bodies bearing spores
- C Dormant cysts
- D Motile flagellated swarm cells
Correct answer: Fruiting bodies bearing spores
When conditions become unfavorable, the plasmodium of a slime mould differentiates to form fruiting bodies. These structures bear spores at their tips, and the spores possess true walls that can withstand harsh conditions.
Dinoflagellates usually possess how many flagella?
- A One, located at the apex
- B Two: one longitudinal, one transverse
- C Multiple, covering the entire body surface
- D None, as they are non-motile
Correct answer: Two: one longitudinal, one transverse
Most dinoflagellates possess two flagella. One lies longitudinally and the other transversely within a furrow between the stiff cellulose plates of the cell wall, enabling spiral movement.
Which protozoan group uses pseudopodia for capturing prey?
- A Amoeboid protozoans
- B Flagellated protozoans
- C Ciliated protozoans
- D Sporozoans
Correct answer: Amoeboid protozoans
Amoeboid protozoans, such as Amoeba, move and capture their prey by putting out pseudopodia (false feet). Marine forms of this group may have silica shells on their surface.
The boundaries of Kingdom Protista are not well-defined because:
- A Their cells entirely lack any membrane-bound nucleus
- B Many members share traits with plants, fungi, or animals, so boundaries are disputed
- C They are incapable of any form of sexual reproduction
- D All members are consistently multicellular with clearly differentiated tissues and organs
Correct answer: Many members share traits with plants, fungi, or animals, so boundaries are disputed
Kingdom Protista acts as a biological 'junk drawer' for unicellular eukaryotes. Because many members share traits with plants, fungi, or animals, scientists often disagree on their exact classification, making the kingdom's boundaries inherently fuzzy.
Being eukaryotes, the protist cell body contains:
- A Only 70S ribosomes and no membrane-bound organelles
- B Naked circular DNA lacking associated histone proteins
- C A membrane-bound nucleus and membrane-bound organelles
- D No mitochondria, obtaining energy exclusively through glycolysis
Correct answer: A membrane-bound nucleus and membrane-bound organelles
Protists are eukaryotic organisms, meaning they possess a true nucleus enclosed by a nuclear membrane. They also contain membrane-bound organelles such as mitochondria, Golgi bodies, and — in photosynthetic forms — chloroplasts.
Which of the following is an example of an amoeboid protozoan that is a parasite?
- A Amoeba proteus
- B Entamoeba
- C Trypanosoma
- D Euglena
Correct answer: Entamoeba
Entamoeba histolytica is a parasitic amoeboid protozoan. It lives in the human large intestine and causes amoebic dysentery, a serious gastrointestinal infection.
Diatomaceous earth is used in all the following EXCEPT:
- A Abrasive polishing
- B Filtration of oils
- C Clarification of syrups
- D Production of biogas
Correct answer: Production of biogas
Because diatomaceous earth is gritty and porous, it is used for abrasive polishing and the filtration and clarification of oils and syrups. Biogas production is associated with methanogenic archaea, not with diatomaceous earth.
Protists reproduce asexually and sexually, the latter involving:
- A Binary fission exclusively, producing identical clones
- B Fusion of cells to form a zygote
- C Budding
- D Vegetative fragmentation into daughter cells
Correct answer: Fusion of cells to form a zygote
Sexual reproduction in protists involves the fusion of two cells (gametes), producing a diploid zygote. This process introduces genetic variation into the population and is distinct from the asexual methods of binary fission, budding, and fragmentation.
The spores of slime moulds are dispersed by:
- A Water currents
- B Air currents
- C Insects
- D Active swimming
Correct answer: Air currents
The spores produced by slime moulds are extremely resistant and can survive for many years under adverse conditions. These spores are eventually dispersed by air currents.
In most dinoflagellates, the cell wall has stiff plates made of:
- A Silicic acid
- B Chitin
- C Cellulose
- D Pectin
Correct answer: Cellulose
Dinoflagellates are characterized by stiff cellulose plates on the outer surface of their cell walls, giving them a distinct armored appearance under a microscope.