Biological Classification
Test 5

Correct answer Carries: 4.

Wrong Answer Carries: -1.

An organism is unicellular, has a well-defined nucleus and may possess cilia or flagella. In which kingdom should it be placed?

Monera
Protista
Fungi
Animalia
2

A unicellular organism with a well-defined nucleus is eukaryotic and therefore does not belong to Monera. Kingdom Protista includes single-celled eukaryotes, some of which possess cilia or flagella.

An archaebacterium survives in an extremely salty habitat. Which combination correctly identifies it and explains its survival?

Methanogen; presence of chlorophyll a
Thermoacidophile; absence of genetic material
Halophile; a cell-wall structure different from that of other bacteria
Cyanobacterium; formation of heterocysts
3

Archaebacteria living in extremely salty areas are called halophiles. Their cell-wall structure differs from that of other bacteria, and this difference helps them survive under extreme conditions.

A bacterium oxidises ammonia and uses the released energy to produce ATP. How should it be classified?

Chemosynthetic autotroph
Saprophytic heterotroph
Parasitic heterotroph
Photosynthetic autotroph
4

Chemosynthetic autotrophic bacteria oxidise inorganic substances such as ammonia, nitrites and nitrates. They use the energy released during oxidation for ATP production and synthesise their own food.

An aquatic microscopic organism has a wall made of two overlapping silica-containing shells. Which additional statement should also be correct?

It is a diatom and may contribute to diatomaceous earth.
It is a dinoflagellate with stiff cellulose plates.
It is a euglenoid with a protein-rich pellicle.
It is a slime mould that forms a plasmodium.
1

Diatom cell walls consist of two thin, overlapping shells embedded with silica. Their indestructible wall deposits accumulate over long periods and form diatomaceous earth.

A marine protist has stiff cellulose plates and two differently positioned flagella. If it multiplies rapidly, what may occur?

Formation of diatomaceous earth
A red tide that may kill fishes
Production of methane from dung
Formation of an ascocarp
2

The organism is a dinoflagellate. Red dinoflagellates such as Gonyaulax may multiply rapidly, making the sea appear red. Toxins released by such large populations may kill marine animals such as fishes.

A protozoan has thousands of cilia and a gullet into which food-bearing water is directed. To which group does it belong?

Amoeboid protozoans
Flagellated protozoans
Ciliated protozoans
Sporozoans
3

Ciliated protozoans possess numerous cilia whose coordinated movement directs water laden with food into a cavity called the gullet. Paramoecium is the example given for this group.

In a fungal sexual cycle, plasmogamy occurs but the nuclei do not fuse immediately. What condition is formed before karyogamy?

A dikaryotic condition with two nuclei per cell
A diploid zygote containing one nucleus
A haploid spore formed by mitosis
A coenocytic condition without nuclei
1

In Ascomycetes and Basidiomycetes, plasmogamy may be followed by an intervening dikaryotic stage before karyogamy. Each cell then contains two haploid nuclei, represented as n + n, and the phase is called the dikaryophase.

A fungus has branched septate mycelium, generally lacks asexual spores and produces four spores externally on a specialised structure. Which class does it belong to?

Phycomycetes
Ascomycetes
Basidiomycetes
Deuteromycetes
3

Basidiomycetes possess branched, septate mycelium and generally lack asexual spores. Karyogamy and meiosis occur in a basidium, usually producing four basidiospores externally.

A virus infects an animal. Which genetic material could it possess according to the chapter?

Only single-stranded DNA
Both RNA and DNA in the same virus
Protein only, without nucleic acid
Single- or double-stranded RNA, or double-stranded DNA
4

Animal viruses may contain single-stranded RNA, double-stranded RNA or double-stranded DNA. A virus contains either RNA or DNA as its genetic material, but never both.

In a lichen, one partner prepares food while the other provides shelter and absorbs water and mineral nutrients. Which pairing is correct?

Mycobiont prepares food; phycobiont provides shelter.
Both partners are autotrophic and prepare food independently.
Phycobiont prepares food; mycobiont provides shelter and absorbs water and minerals.
Both partners are fungi with identical functions.
3

The phycobiont is the autotrophic algal partner and prepares food. The mycobiont is the heterotrophic fungal partner; it provides shelter and absorbs mineral nutrients and water for the association.

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