Biological Classification Chapter-Wise Test 15

Correct answer Carries: 4.

Wrong Answer Carries: -1.

A composite organism contains an autotrophic partner that prepares food and a fungal partner that provides shelter and absorbs water and minerals. Which observation is most consistent with its identity?

It grows abundantly in polluted areas.
It is generally absent from polluted areas.
Both partners are heterotrophic.
It consists of a fungus and a plant root.
2

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

An organism absorbs soluble organic matter, possesses a wall containing chitin and stores food as glycogen and oil droplets. In which kingdom should it be placed?

Monera
Protista
Fungi
Plantae
3

The organism belongs to Kingdom Fungi. Fungi are absorptive heterotrophs, their walls contain chitin and other polysaccharides, and their reserve food is stored as glycogen and oil droplets.

Protozoan X captures prey using pseudopodia, protozoan Y directs food-bearing water into a gullet using cilia, and protozoan Z has an infectious spore-like stage. Which identification is correct?

X—amoeboid; Y—ciliated; Z—sporozoan
X—ciliated; Y—flagellated; Z—amoeboid
X—sporozoan; Y—amoeboid; Z—ciliated
X—flagellated; Y—sporozoan; Z—amoeboid
1

Amoeboid protozoans use pseudopodia for movement and food capture. Ciliated protozoans use coordinated cilia to direct food-bearing water into a gullet, while sporozoans possess an infectious spore-like stage in their life cycle.

Bacteria normally reproduce by fission. Under different circumstances, some form spores while others transfer DNA between cells. Which interpretation is correct?

Spore formation aids survival, while DNA transfer represents a primitive type of sexual reproduction.
Both processes are forms of mitosis.
Spore formation is the usual method of bacterial multiplication.
DNA transfer produces a multicellular bacterial body.
1

Bacteria reproduce mainly by fission. Some produce spores under unfavourable conditions, while a primitive type of sexual reproduction may occur through the transfer of DNA from one bacterial cell to another.

An aquatic microscopic eukaryote floats passively with plankton and has two overlapping silica-containing wall layers. Which conclusion follows?

It is a dinoflagellate that necessarily causes a red tide.
It is a euglenoid with a protein-rich pellicle.
It is a slime mould that forms a plasmodium.
It is a diatom whose wall deposits may form diatomaceous earth.
4

The organism is a diatom. Diatoms have two thin, overlapping wall layers embedded with silica. Their indestructible wall deposits accumulate over long periods and form diatomaceous earth.

A freshwater protist lacks a cell wall, possesses a flexible protein-rich covering and has one short and one long flagellum. How does it behave when sunlight is unavailable?

It forms resistant spores inside fruiting bodies.
It fixes atmospheric nitrogen in heterocysts.
It preys on smaller organisms as a heterotroph.
It produces basidiospores externally.
3

The organism is a euglenoid. Euglenoids possess a flexible pellicle and two unequal flagella. They photosynthesise in sunlight but behave as heterotrophs by preying on smaller organisms when sunlight is unavailable.

A group of heterotrophic bacteria includes useful forms involved in food preparation and other forms that recycle dead organic matter. Which pair of roles is described?

Conversion of milk into curd and decomposition
Formation of red tides and production of spores in asci
Formation of diatomaceous earth and photosynthesis
Production of basidiocarps and heterocysts
1

Some heterotrophic bacteria help convert milk into curd. Most heterotrophic bacteria act as important decomposers and obtain nutrients from dead organic matter.

An infectious agent associated with potato spindle tuber disease is smaller than viruses and lacks a protein coat. Which description identifies it correctly?

A prion consisting of abnormally folded protein
A viroid consisting of free RNA of low molecular weight
A virus containing both RNA and DNA
A bacteriophage enclosed by a cellular wall
2

The agent is a viroid. T. O. Diener discovered viroids while studying potato spindle tuber disease. Viroids consist of free RNA of low molecular weight and lack the protein coat found in viruses.

Which sequence correctly represents the major events of sexual reproduction in fungi?

Karyogamy → meiosis → plasmogamy
Meiosis → budding → plasmogamy
Plasmogamy → karyogamy → meiosis
Fission → fragmentation → karyogamy
3

Fungal sexual reproduction involves plasmogamy, or fusion of protoplasms; karyogamy, or fusion of nuclei; and meiosis in the zygote, which produces haploid spores.

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

It reproduces independently by fission outside the host.
It oxidises inorganic substances to produce ATP.
It forms a plasmodium before entering the host.
It takes over the machinery of the host cell for replication.
4

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

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