Recognise the Major Protist Groups
These questions test recognition: connect each protist group to its habitat, cell feature, movement, or ecological role.
Protista is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Start with the kingdom pattern
In the five-kingdom scheme used here, Protista contains mainly unicellular eukaryotes. They have a true nucleus and membrane-bound organelles, and many live in water. Do not place every single-celled organism in Protista: Monera are prokaryotic. Protists show both asexual and sexual modes of reproduction across the group.
Chrysophytes: silica and the ocean
Diatoms are photosynthetic plankton and major primary producers in oceans. Their cell walls contain silica and fit together like two overlapping shells. Accumulated silica-rich walls form diatomaceous earth, used for filtration and polishing; it is not a source of biogas.
Dinoflagellates: two flagella and red tides
Most dinoflagellates are marine. Their cellulose plates form a stiff covering, and two flagella lie in grooves at right angles to each other. Pigments can make them appear yellow, green, brown, blue, or red. Rapid blooms by toxin-producing forms such as Gonyaulax can kill fish and other marine animals.
Euglenoids and slime moulds
Euglenoids lack a cell wall and have a flexible, protein-rich pellicle. They use chlorophyll a and b in light and can feed heterotrophically when light is unavailable. Slime moulds feed saprophytically; their spreading vegetative plasmodium is a naked, multinucleate mass. The pictured Physarum stage therefore has no cell wall.
Protozoans: read the movement clue
Amoeba moves with pseudopodia, temporary cytoplasmic projections often called false feet. When an option calls them true feet, the wording is the trap. Link the structure or movement clue to the organism before judging the whole statement.
OlympIQ exam lens
- ✓Protista is eukaryotic; Monera is prokaryotic.
- ✓Diatoms: silica shells, plankton, ocean production, and diatomaceous earth.
- ✓Dinoflagellates: mostly marine, cellulose plates, two perpendicular flagella; Gonyaulax can cause toxic blooms.
- ✓Euglenoids: chlorophyll a and b, flexible pellicle, heterotrophy without light.
- ✓Slime-mould plasmodium is naked and multinucleate; Amoeba uses pseudopodia.
Sort by the distinctive clue first: silica points to diatoms, cellulose plates and two grooves to dinoflagellates, a flexible pellicle to euglenoids, and a naked plasmodium to slime moulds.
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