NEET Biology Biological Classification MCQs Set 15

Answer: (d) They show bioluminescence

Explanation:
1. Some dinoflagellates such as Noctiluca emit light, so the sea glows at night.
2. This bioluminescence gives the name.

Teacher's Note:
1. It is a chemical light.
2. Not heat.

Answer: (b) Paralysis

Explanation:
1. Saxitoxin from dinoflagellates collects in shellfish.
2. Eating them causes paralytic shellfish poisoning.

Teacher's Note:
1. Red tides kill fish this way.
2. Gonyaulax produces the toxin.

Answer: (c) Fire algae

Explanation:
1. Dinoflagellates have chromosomes that stay condensed and lack histones.
2. This is why they are called mesokaryotes.

Teacher's Note:
1. Their nucleus is intermediate between prokaryote and eukaryote.
2. Other eukaryotes have histones.

Answer: (c) Floating

Explanation:
1. Diatoms are planktonic and drift or float.
2. They have no organs for active swimming.

Teacher's Note:
1. They are part of plankton.
2. Some move by gliding on surfaces.

Answer: (d) Gametic meiosis

Explanation:
1. In diploid protists the meiosis comes before gamete formation (gametic meiosis).
2. Zygotic meiosis is seen in haploid forms.

Teacher's Note:
1. Gametic meiosis is typical of diplontic life cycles.
2. Haploid forms meiose in the zygote.

Answer: (b) Dinoflagellates

Explanation:
1. Rapid multiplication of red dinoflagellates such as Gonyaulax makes the sea look red.
2. This is a red tide.

Teacher's Note:
1. Red tides kill fish.
2. Toxins reach humans through shellfish.

Answer: (b) Autoecious

Explanation:
1. Autoecious fungi complete the whole life cycle on one host.
2. Heteroecious fungi need two hosts, like Puccinia.

Teacher's Note:
1. Puccinia is heteroecious (wheat and barberry).
2. Heterothallic means separate mating types.

Answer: (d) All of the above

Explanation:
1. Both are heterotrophs, store glycogen and have chitin in the body (the fungal wall, the arthropod skeleton).
2. So all three are shared.

Teacher's Note:
1. Fungi are closer to animals than to plants.
2. Plants store starch and make cellulose walls.

Answer: (a) Ascomycetes

Explanation:
1. Ascomycetes produce their sexual spores (ascospores) inside sac-like asci, hence sac fungi.
2. Basidiomycetes are club fungi.

Teacher's Note:
1. Examples: yeast, Neurospora, Penicillium (sexual stage), Aspergillus.
2. Mycelium is septate and branched.

Answer: (d) All of the above

Explanation:
1. Rusts (Puccinia), smuts (Ustilago) and mushrooms (Agaricus) are all club fungi.
2. So all three belong to Basidiomycetes.

Teacher's Note:
1. Basidiospores are borne outside on basidia.
2. Dikaryotic mycelium is common.

Answer: (c) A fungus

Explanation:
1. Wheat rust is caused by the fungus Puccinia graminis tritici.
2. It is a basidiomycete.

Teacher's Note:
1. It has two hosts: wheat and barberry.
2. It is heteroecious.

Answer: (d) Heterotrophic

Explanation:
1. Fungi lack chlorophyll and absorb ready-made food from their surroundings.
2. They are saprophytes, parasites or symbionts.

Teacher's Note:
1. Absorptive nutrition.
2. Not holozoic.

Answer: (b) Without chlorophyll

Explanation:
1. Fungi are non-photosynthetic and have no chlorophyll.
2. They have a chitinous cell wall.

Teacher's Note:
1. They are heterotrophs.
2. Carotenoids may occur but not chlorophyll.

Answer: (d) Both Rhizopus and Mucor

Explanation:
1. Rhizopus and Mucor are phycomycetes with aseptate coenocytic hyphae.
2. Penicillium has septate hyphae.

Teacher's Note:
1. Both reproduce by sporangiospores.
2. Rhizopus is the bread mould.

Answer: (d) Glycogen and oil

Explanation:
1. Fungi store glycogen and oil droplets.
2. They do not make starch, and cellulose is a wall material.

Teacher's Note:
1. Glycogen is also the animal reserve.
2. Plants store starch.

Answer: (c) Formation of ascospores

Explanation:
1. Ascomycetes form ascospores in asci.
2. Spores and hyphae occur in all fungi.

Teacher's Note:
1. Ascus is a sac.
2. Usually 8 ascospores.

Answer: (b) Neurospora

Explanation:
1. Neurospora is the genetic model of the plant kingdom.
2. It grows fast and its haploid spores show Mendelian ratios directly.

Teacher's Note:
1. Morchella is an edible morel.
2. Claviceps causes ergot.

Answer: (d) The complete basidiocarp

Explanation:
1. The mushroom you eat is the whole fruiting body, the basidiocarp.
2. The mycelium lies in the soil.

Teacher's Note:
1. Agaricus bisporus is the common edible mushroom.
2. The basidiocarp bears gills with basidia.

Answer: (c) Saccharomyces

Explanation:
1. Saccharomyces (yeast) is unicellular and has no mycelium.
2. The others form hyphae.

Teacher's Note:
1. Yeast reproduces by budding.
2. It is used in baking and brewing.

Answer: (b) K. C. Mehta

Explanation:
1. K. C. Mehta worked out the life cycle of wheat rust (Puccinia) in India.
2. He showed that the uredospores spread the disease from the hills to the plains.

Teacher's Note:
1. Mehta studied the rust in Agra.
2. Luthra worked on seed pathology.

Answer: (c) They have no sexual reproduction

Explanation:
1. Only asexual (conidial) reproduction is known in the group.
2. The sexual stage is lacking or unknown.

Teacher's Note:
1. Perfect fungi show both modes.
2. Alternaria, Colletotrichum, Trichoderma are examples.

Answer: (b) Fungi

Explanation:
1. Fungi secrete digestive enzymes outside and absorb the digested food through the hyphal wall.
2. Algae and bryophytes are autotrophic.

Teacher's Note:
1. Euglenoids are mixotrophic.
2. Hyphae have a large surface area.

Answer: (a) Deuteromycetes

Explanation:
1. A form class is grouped by form (asexual stage) when the sexual stage is unknown.
2. Deuteromycetes are called a form class.

Teacher's Note:
1. Also called fungi imperfecti.
2. Based on convenience.

Answer: (a) Ascomycetes

Explanation:
1. Ergot is caused by Claviceps purpurea, an ascomycete.
2. It infects rye and produces toxic alkaloids.

Teacher's Note:
1. The sclerotia are the ergot.
2. LSD is derived from ergot.

Answer: (b) Bacteria (Staphylococcus)

Explanation:
1. Fleming was culturing Staphylococcus when a Penicillium mould contaminated a plate and killed the bacteria around it.
2. So he was working with Staphylococcus.

Teacher's Note:
1. The mould was P. notatum.
2. It was the first antibiotic.

Answer: (c) Mycelium

Explanation:
1. The hyphae together form the mycelium.
2. Haustoria are absorptive branches of hyphae in parasites.

Teacher's Note:
1. A hypha is a single filament.
2. Thallus is a general term for an undifferentiated body.

Answer: (d) Heterotrophs

Explanation:
1. Not all fungi are symbionts, parasites or saprophytes, but all lack chlorophyll and are heterotrophic.
2. So heterotrophs is the correct universal term.

Teacher's Note:
1. Heterotrophs depend on ready-made food.
2. Fungi absorb food.