Biological Classification Chapter-Wise Test 9

Correct answer Carries: 4.

Wrong Answer Carries: -1.

An aquatic microscopic eukaryote floats passively with plankton and possesses a wall made of two thin, overlapping silica-containing shells. Which conclusion is correct?

It is a dinoflagellate and must produce a red tide.
It is a euglenoid with a protein-rich pellicle.
It is a diatom and may contribute to the formation of diatomaceous earth.
It is a slime mould that forms a plasmodium.
3

The organism is a diatom. Diatoms have two overlapping silica-containing wall layers and form part of the plankton. Their accumulated, indestructible wall deposits form diatomaceous earth.

A marine photosynthetic protist has stiff cellulose plates and two flagella placed in different orientations. Which additional observation would support its identification?

One flagellum is longitudinal and the other is transverse.
Its wall consists of two overlapping silica shells.
It has one short and one long flagellum and lacks a cell wall.
It moves and captures prey through pseudopodia.
1

The organism is a dinoflagellate. Most dinoflagellates possess one longitudinal flagellum and one transverse flagellum lying in a furrow between the cellulose plates.

An organism has a cell wall, lacks chlorophyll and obtains dissolved nutrients by absorption from dead organic matter. In which kingdom should it be placed?

Plantae
Animalia
Fungi
Protista
3

The organism belongs to Kingdom Fungi. Fungi are heterotrophic, possess walls containing chitin and other polysaccharides, and absorb soluble organic matter from dead substrates or living hosts.

An organism is unicellular, aquatic and possesses a well-defined nucleus and membrane-bound organelles. Which kingdom is the best placement for it?

Monera
Protista
Plantae
Animalia
2

Kingdom Protista includes single-celled eukaryotes. Their cells possess a well-defined nucleus and membrane-bound organelles, and most protists are aquatic.

A bacterium encounters unfavourable environmental conditions. Which response described in the chapter may help it persist?

Formation of an ascocarp
Development of a plasmodium
Production of basidiospores on basidia
Formation of spores
4

Bacteria reproduce mainly by fission, but under unfavourable conditions some bacteria produce spores. Ascocarps, plasmodia and basidia belong to fungi or slime moulds rather than bacteria.

An infectious particle remains inert outside a living cell but produces new particles after entering a suitable host. Which explanation best accounts for this behaviour?

It takes over the machinery of the host cell for replication.
It divides independently by fission outside the host.
It produces its own cellular organelles before infection.
It obtains energy by oxidising inorganic substances.
1

The particle is a virus. Viruses are inert outside their specific host cells but take over host-cell machinery after infection to produce additional virus particles.

A very small prokaryotic cell survives without oxygen and causes disease in plants or animals. Which structural feature identifies it as Mycoplasma?

Presence of stiff cellulose plates
Presence of a silica-containing shell
Complete absence of a cell wall
Presence of a membrane-bound nucleus
3

Mycoplasma completely lack a cell wall. They are the smallest living cells known, can survive without oxygen and include forms that cause diseases in plants and animals.

A prokaryotic organism contains chlorophyll a, forms colonies surrounded by a gelatinous sheath and may possess specialised nitrogen-fixing cells. Which group is described?

Dinoflagellates
Euglenoids
Diatoms
Cyanobacteria
4

Cyanobacteria are photosynthetic prokaryotes containing chlorophyll a. Their colonies commonly have a gelatinous sheath, and some forms possess nitrogen-fixing heterocysts.

An organism belongs to Monera and survives in an extremely salty habitat because its cell wall differs from that of other bacteria. How should it be classified?

Methanogenic cyanobacterium
Halophilic archaebacterium
Photosynthetic protist
Saprophytic fungus
2

Halophiles are archaebacteria that live in extremely salty areas. The cell-wall structure of archaebacteria differs from that of other bacteria and enables them to survive in extreme habitats.

A composite organism contains an autotrophic partner that prepares food and a heterotrophic partner that provides shelter and absorbs water and minerals. Which further observation is expected?

Both partners possess chlorophyll.
The fungal partner performs photosynthesis.
It is generally absent from polluted areas.
It consists of a fungus and a plant root.
3

The organism is a lichen. Its algal partner prepares food, while its fungal partner provides shelter and absorbs water and minerals. Lichens do not grow in polluted areas and therefore indicate air pollution.

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