Free Kingdom Protista MCQs with Answers

141. Choanoflagellates resemble to collar cells in

• A. Sponges
• B. Cnidarians
• C. Ciliates
• D. Actinopods

Explanation: Choanoflagellates are single-celled organisms that have a distinctive structure featuring a collar of microvilli surrounding a single flagellum. This structure is remarkably similar to the choanocytes (collar cells) found in sponges, which also use a similar mechanism to filter food particles from the water. This similarity suggests a close evolutionary relationship between choanoflagellates and sponges. The other options, such as cnidarians, ciliates, and actinopods, do not share this specific cellular structure.

142. Protists with two nuclei

• A. Actinopods
• B. Zooflagellates
• C. Ciliates
• D. Apicomplexans

Explanation: Ciliates are a group of protists distinguished by having two types of nuclei: a macronucleus and one or more micronuclei. The macronucleus controls non-reproductive cell functions, while the micronuclei are involved in reproductive processes. This distinct feature sets them apart from other protists. Actinopods, zooflagellates, and apicomplexans do not typically have two nuclei; instead, they are characterized by other features such as their movement mechanisms or parasitic nature.

143. A sessile ciliate

• A. Radiolarian
• B. Apicomplexan
• C. Stentor
• D. Trichonympha

Explanation: The correct answer is Stentor. Stentor is a sessile ciliate, meaning it is typically attached to substrates in its environment. Its unique trumpet-like shape allows it to effectively filter feed. Radiolarian are not sessile; they are free-floating and primarily marine organisms with siliceous skeletons. Apicomplexan are parasitic and not characterized by being sessile or having cilia. Trichonympha are flagellates, not ciliates, and live symbiotically in the guts of termites, not as sessile organisms.

144. Protozoa which produce shells

• A. Foraminiferans
• B. Amoebas
• C. Apicomplexans
• D. Ciliates

Explanation: The correct answer is Foraminiferans. Foraminiferans are a group of protozoans that produce shells, often made of calcium carbonate. These shells, also known as tests, are complex and vary greatly in shape and structure. In contrast, Amoebas do not have shells and are characterized by their flexible membranes and movement via pseudopodia. Apicomplexans are primarily known as parasites and do not form shells, while Ciliates use cilia for movement and feeding and also do not produce shells.

145. Responsible for creation of vast limestone deposits

• A. Apicomplexans
• B. Ciliates
• C. Protozoans
• D. Foraminiferans

Explanation: Foraminiferans are single-celled protists with shells made of calcium carbonate. When foraminiferans die, their shells settle on the ocean floor, accumulating over time to form limestone deposits. This distinguishes them from other protists like Apicomplexans and Ciliates, which do not contribute to limestone formation. Protozoans is a broader category that includes foraminiferans, but not all protozoans form limestone deposits.

146. Actinopods contain

• A. Cilia
• B. Flagella
• C. Tests
• D. Pseudopodia

Explanation: Actinopods are a group of protists that are characterized by their intricate and delicate skeletons known as tests. These tests provide structural support and protection. While actinopods do extend pseudopodia through openings in their tests, the defining feature is indeed their tests. Cilia and flagella are not typically associated with actinopods as their primary structures, making these options incorrect.

147. The actinopods with glassy shells

• A. Stentor
• B. Euglena
• C. Radiolarians

Explanation: Radiolarians are a class of protists within the broader group of actinopods. They are known for their beautiful and intricate silica-based, glassy shells. These shells often have radial symmetry and are used for protection and buoyancy. In contrast, Stentor and Euglena are protists that do not have glassy shells. Stentor are ciliate protists known for their trumpet-like shape, and Euglena are flagellated and primarily photosynthetic, lacking any form of silica-based shell.

148. The cause of malaria is

• A. Amoeba
• B. Paramecium
• C. Chlorella
• D. Plasmodium

Explanation: The correct answer is Plasmodium. Plasmodium is a group of parasitic protozoa that causes malaria in humans. Malaria is transmitted through the bites of infected female Anopheles mosquitoes, which carry the Plasmodium parasites. Once inside the human body, these parasites multiply in the liver and infect red blood cells.The other options are incorrect as they refer to organisms unrelated to the cause of malaria. Amoeba can cause amoebic dysentery, Paramecium is a non-parasitic ciliate found in water environments, and Chlorella is a type of algae that is not pathogenic to humans.

149. The protists which form spores after meiosis

• A. Myxomycota
• B. Oomycetes
• C. Dinoflagellates
• D. Apicomplexans

Explanation: The correct answer is Apicomplexans. Apicomplexans are a group of protists that are characterized by their ability to form spores following meiosis. This is a crucial part of their life cycle, especially in parasitic species such as Plasmodium, which causes malaria. They undergo sexual reproduction that leads to the formation of spores, aiding in their transmission and infection processes. The other options, such as Myxomycota, Oomycetes, and Dinoflagellates, have different reproductive strategies or lifecycle characteristics that do not primarily involve spore formation immediately after meiosis.

150. The simultaneous bursting of millions of which type of cells causes the symptoms of malaria

• A. White blood cells
• B. Red blood cells
• C. Platelets
• D. All of these

Explanation: Malaria symptoms are caused by the simultaneous bursting of millions of red blood cells, a process induced by the malaria parasite, Plasmodium. When these parasites multiply within red blood cells, they eventually cause the cells to burst, releasing more parasites into the bloodstream and leading to symptoms such as fever and chills. White blood cells and platelets are not involved in this process, as they have different roles in the body.