Biological Classification Chapter-Wise Test 13

Correct answer Carries: 4.

Wrong Answer Carries: -1.

A saprophytic protist moves over decaying leaves and twigs, engulfing organic material. Under favourable conditions it forms a large spreading mass, but under adverse conditions it produces resistant spores. Which organism is described?

Slime mould
Diatom
Euglenoid
Cyanobacterium
1

Slime moulds are saprophytic protists that engulf organic material from decaying vegetation. Under suitable conditions they form a plasmodium, while unfavourable conditions induce fruiting bodies bearing resistant spores.

Two infectious agents are compared. Agent X consists of free, low-molecular-weight RNA without a protein coat, whereas agent Y consists only of abnormally folded protein. Which identification is correct?

X—virus; Y—bacterium
X—viroid; Y—prion
X—prion; Y—viroid
X—bacteriophage; Y—virus
2

A viroid consists of free RNA of low molecular weight and lacks a protein coat. A prion is an infectious agent composed of abnormally folded protein and contains no nucleic acid.

A plant-pathogenic fungus causes rust disease, generally lacks asexual spores and produces sexual spores externally on a specialised structure. Which classification is correct?

Ascomycetes producing ascospores inside asci
Phycomycetes producing zoospores inside sporangia
Deuteromycetes producing only zygospores
Basidiomycetes producing basidiospores on basidia
4

Rust fungi such as Puccinia are Basidiomycetes. Karyogamy and meiosis occur in a basidium, and basidiospores are produced externally on it.

Protozoan X moves and captures prey using pseudopodia, while protozoan Y possesses an infectious spore-like stage in its life cycle. Which pairing is correct?

X—ciliated protozoan; Y—flagellated protozoan
X—sporozoan; Y—amoeboid protozoan
X—amoeboid protozoan; Y—sporozoan
X—flagellated protozoan; Y—ciliated protozoan
3

Amoeboid protozoans use pseudopodia for movement and food capture. Sporozoans possess an infectious spore-like stage; Plasmodium is the example given for this group.

A fungus used extensively in biochemical and genetic work has branched, septate mycelium and produces sexual spores inside asci. Which organism and class are correctly matched?

Neurospora—Ascomycetes
Ustilago—Phycomycetes
Albugo—Basidiomycetes
Gonyaulax—Deuteromycetes
1

Neurospora is an Ascomycete used extensively in biochemical and genetic work. Ascomycetes possess branched, septate mycelium and form sexual ascospores inside asci.

An aquatic protozoan possesses thousands of short locomotory structures whose coordinated movement directs food-bearing water into a gullet. Which organism is the best example?

Amoeba
Trypanosoma
Paramoecium
Plasmodium
3

Paramoecium is a ciliated protozoan. Coordinated movement of its numerous cilia directs water containing food into a cavity called the gullet.

A prokaryotic colony contains chlorophyll a, is surrounded by a gelatinous sheath and forms a bloom in polluted water. Which further feature may occur in some members?

Nitrogen fixation in heterocysts
Production of ascospores inside asci
Formation of a protein-rich pellicle
Production of basidiospores on basidia
1

The organism is a cyanobacterium. Cyanobacterial colonies commonly possess a gelatinous sheath and may form blooms in polluted water. Some forms, such as Nostoc and Anabaena, fix atmospheric nitrogen in heterocysts.

A composite organism is absent from a polluted locality. Its photosynthetic partner supplies food, while its fungal partner provides shelter and absorbs water and minerals. Which conclusion follows?

It is a mycorrhiza and the plant root prepares food.
It is a lichen and can indicate air pollution.
It is a slime mould and forms a plasmodium.
It is a cyanobacterial colony and forms heterocysts.
2

The association is a lichen. The algal phycobiont prepares food, while the fungal mycobiont provides shelter and absorbs water and minerals. Because lichens do not grow in polluted areas, they indicate air pollution.

A unicellular fungus used in making bread and beer is placed among sac fungi. Which combination of features is consistent with this classification?

Puccinia—Ascomycetes—zoospores are formed
Rhizopus—Basidiomycetes—conidia are formed
Albugo—Deuteromycetes—basidiospores are formed
Yeast—Ascomycetes—budding may occur
4

Yeast is a unicellular fungus used in preparing bread and beer and belongs to Ascomycetes. Budding is one of the vegetative methods of reproduction described for fungi.

A fungus is placed in Deuteromycetes because only its vegetative and asexual stages are known. What should happen if its sexual stage is later found to produce basidiospores?

It should remain in Deuteromycetes permanently.
It should be transferred to Basidiomycetes.
It should be transferred to Phycomycetes.
It should be placed in Kingdom Protista.
2

Deuteromycetes contain fungi whose sexual stages are not known. Once the sexual stage is discovered, the fungus is transferred to the appropriate class. Production of basidiospores identifies the sexual form as a Basidiomycete.

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