Free Kingdom Protista MCQs with Answers

161. Pinnularia belongs to

• A. Chlorophyta
• B. Chrysophyta
• C. Pheophyta
• D. Rhodophyta

Explanation: Pinnularia is a genus of diatoms, which belong to the division Chrysophyta. Diatoms are a type of algae that have a unique silica cell wall known as a frustule, giving them their characteristic appearance. Chrysophyta, often termed as golden algae, includes these unicellular organisms. Chlorophyta, Pheophyta, and Rhodophyta represent green, brown, and red algae respectively, which differ in pigmentation, habitat, and cellular structure. Thus, the correct answer is Chrysophyta.

162. The giants of protists are included in

• A. Green algae
• B. Brown algae
• C. Red algae
• D. Golden algae

Explanation: Brown algae are known as the giants of the protist kingdom because they include some of the largest and most structurally complex protists, such as kelp. Kelp can grow to significant lengths, forming dense underwater forests. Green algae, red algae, and golden algae, while important and diverse, do not include species that match the size and complexity of brown algae.

163. Member of which groups of algae may be more than 75 meters in length

• A. The euglenoids
• B. Diatoms
• C. Brown algae
• D. Red algae

Explanation: Brown algae, specifically those in the order Laminariales, commonly known as kelp, are known to form large and complex multicellular structures. These algae can grow to impressive lengths, with some species reaching over 75 meters. This makes them the correct answer. Euglenoids are not typically large and do not form multicellular structures. Diatoms, while abundant and ecologically significant, are single-celled and microscopic. Red algae, although diverse, generally do not grow as large as brown algae and are often found in more compact forms.

164. Algae in which body is differentiated into blades, stipes and holdfast belong to

• A. Golden algae
• B. Euglenoids
• C. Kelps
• D. Diatoms

Explanation: The correct answer is Kelps. Kelps are a type of large brown algae that exhibit complex structural differentiation into blades, stipes, and holdfast, allowing them to anchor to substrates and reach sunlight in aquatic environments. Golden algae, Euglenoids, and Diatoms, on the other hand, do not have these differentiated structures. Golden algae are mostly unicellular or colonial, Euglenoids are flagellated protists, and Diatoms are unicellular with silica-based cell walls.

165. Algae with holdfast, stipe and leaf-like blades

• A. Laminaria
• B. Volvox
• C. Polysiphonia
• D. Ulva

Explanation: The correct answer is Laminaria. Laminaria is a type of brown algae that is characterized by its holdfast, which anchors it to surfaces; a stipe, which acts like a stem; and leaf-like blades that are used for photosynthesis. These features are not present in the other options: Volvox forms colonies and lacks these structures; Polysiphonia has a different, filamentous structure; and Ulva, while having a leaf-like appearance, does not have a stipe or holdfast.

166. Which algae take part in the formation of coral reefs along with coral animals?

• A. Red
• B. Brown
• C. Green
• D. All of these

Explanation: The correct answer is Red algae. Red algae, especially coralline algae, play a significant role in the formation and stabilization of coral reefs by depositing calcium carbonate, which helps build the reef structure. Brown and green algae, while present in marine environments, do not contribute to the actual formation of coral reefs in the same way. Option D is incorrect because not all types of algae are involved in reef formation.

167. An alga in which body is complex and composed of delicate, feathery interwoven filaments

• A. Laminaria
• B. Volvox
• C. Polysiphonia
• D. Ulva

Explanation: The correct answer is Polysiphonia. Polysiphonia is known for its intricate body structure composed of delicate, feathery interwoven filaments, which matches the description in the question. Laminaria and Ulva have larger, flat structures that do not fit the description of interwoven filaments, while Volvox forms spherical colonies. Thus, they are not the correct answers.

168. Green algae is considered the ancestor of land plants due to

• A. Have chlorophyll 'a' and 'b'
• B. Starch as storage of energy
• C. Cell wall of cellulose
• D. All of these

Explanation: The correct answer is All of these. Green algae are considered the ancestors of land plants because they share several key characteristics: they contain chlorophyll 'a' and 'b' for photosynthesis, use starch as a storage form of energy, and have cell walls made of cellulose. Each of these traits is also found in land plants, supporting the idea that land plants evolved from green algae. The other options, while correct in their own right, do not individually account for the full array of similarities that make green algae a strong candidate for the ancestor of land plants.

169. Which substance indicates that green algae and plants form monophyletic lineage?

• A. Genetic material
• B. Lipids
• C. Protein
• D. Carbohydrates

Explanation: The correct answer is Genetic material. Genetic material, particularly DNA sequences, is used to trace evolutionary relationships and demonstrates that green algae and plants share a common ancestor, forming a monophyletic lineage. This shared genetic heritage is a more definitive indicator of their evolutionary relationship than other substances like lipids, proteins, or carbohydrates, which are present in many different organisms and do not specifically indicate common ancestry.

170. One of the following is not green algae

• A. Ulva
• B. Volvox
• C. Kelps
• D. Chlorella

Explanation: The correct answer is Kelps. Kelps are classified as brown algae, not green algae, and belong to the class Phaeophyceae. They are large, multicellular algae found in marine environments and are known for forming kelp forests. In contrast, Ulva, Volvox, and Chlorella are all examples of green algae, characterized by their green color due to the presence of chlorophyll a and b. These green algae can be found in both freshwater and marine environments, but they do not belong to the same group as kelps.