Tag: biology

Questions Related to biology

The botanical name of "Sanjeevani" is

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Selaginella utricularia

  2. Selaginella bryopteris

  3. Selaginella crotalaria

  4. Selaginella botardia

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Correct Option: B
Explanation:

Selaginella bryopteris, known commonly as sanjeevini and sanjivani booti. It is used medicinally in India. The rare life saving herb Sanjeevani known to have been brought by Lord Hanuman to save Lord Laxman. The Hindu mythology Sanjeevani is described as a magical plant which can wake dead people to the life, or which lends immortality. In the high, hostile peaks of the Himalayas where sustaining life is a challenge in itself, scientists say they have found a wonder herb that can regulate the immune system, help adapt to the mountain environment and, above all, protect from radioactivity.

Therefore, the correct answer is option B.

Evolution of seed habit first started in

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Selaginella like ancestral pteridophytes

  2. Psilotum like ancestral pteridophytes

  3. Gymnosperms

  4. Mosses

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Correct Option: A
Explanation:

In majority of the pteridophytes, all the spores are of similar kinds, such plants are called as homosporous. Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores, are known as heterosporous. The megaspores and microspores germinate and give rise to female and male gametophytes, respectively. The female, gametophytes in these plants are retained on the parent sporophytes for variable periods. The development of the zygotes into young embryos take place within the female gametophytes. This event is a precursor to the seed habit considered an important step in evolution.

In Lycopodium, the antherozoids are

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Biflagellate

  2. Multiflagellate

  3. Multiciliate

  4. Non motile

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Correct Option: A
Explanation:

The antherozoid of Lycopodium is pear shaped with two flagella at the anterior end. The biflagellate antherozoids of Lycopodium resemble more to the antherozoids of Bryophytes, rather than those of vascular plants.

Cone bearing Pteridophyta are

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Lycopsida and Psilopsida

  2. Filicinae and Lycopsida

  3. Filicinae and Sphenopsida

  4. Lycopsida and Sphenopsida

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Correct Option: D
Explanation:
Cone bearing Pteridophyta are Lycopsida and Sphenopsida.

Pteridophytes (Gr. pteron= feather, phyton = plant) constitute the most primitive seedless vascular plants that reproduce by means of spores.
They have 4 sub-divisions:

(i) Psilopsida (Psilopsids)

(ii) Lycopsida (Clubmosses),

(iii) Sphenopsida (Horsetails) and

(iv) Pteropsida(Ferns).

Lycopsida:

1. Plant body more advanced and shows differentiation into root, stem and leaves.

2. Leaves are microphyllous (small) having a single unbranched vein in the midrib region.

3. Sporangia are borne in the axil of the fertile leaves (sporophyils).

4. Sporophyll form compact strobili (singularstrobilus). e.g., Lycopodium, Selaginella.

Sphenopsida:

1. Plant body still more advanced and shows differentiation into nodes and internodes like higher vascular plants.

2. Leaves microphyllous, and arise in whorls at each node.

3. Sporangia develop on sporangiophores which form compact cones at the apex of fertile branches (e.g., Equisetum).

Match items in Column I with those in Column II.

   Column I     Column II
 A  Peritrichous flagellation  1  Ginkgo
 B  Living fossil  2  Macrocystis
 C  Rhizophore  3  Escherichia coli
 D  Smallest flowering plant  4  Selaginella
 E  Largest perennial alga  5  Wolffia
classification of pteridophytes kingdom plantae plant kingdom biology

  1. A-3, B-1, C-4, D-5, E-2

  2. A-1, B-2, C-3, D-4, E-5

  3. A-2, B-3, C-4, D-5, E-1

  4. A-3, B-4, C-5, D-2, E-1

Show answer
Correct Option: A
Explanation:

Peritrichous flagellation means having flagella projecting in all directions (e.g., E. coli). 

Gingko, is a living fossil. Newly found specimens that grew more than a hundred million years ago are remarkably similar to present-day plants.
Selaginella has a rhizophore which is a proplike structure that originates at a point of branching and that forks dichotomously after making contact with the soil or a hard surface.
The flower of Wolffia is the smallest known flower in the world, measuring merely 0.3 mm long. It has one stamen and one pistil. 
Macrocystis, a kelp (see weed) is the largest of all algae. The stage of the life cycle that is usually seen is the sporophyte, which is perennial and individuals persist for many years. Therefore correct combination is A-3, B-1, C-4, D-5, E-2. Hence option A is correct.

In Selaginella, reduction division occurs during the formation of

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Sperms

  2. Microspores only

  3. Megaspores only

  4. Both (b) and (c)

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Correct Option: D
Explanation:

The megaspores and microspores germinate and give rise to female and male gametophytes, respectively. The female gametophytes in these plants are retained on the parent sporophytes for variable periods. The development of the zygotes into young embryos take place within the female gametophytes. 

Which of the following is known as 'resurrection plant'?

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Selaginella

  2. Welwitschia

  3. Rafflesia

  4. Chlorella

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Correct Option: A
Explanation:

Selaginella rupestris is xerophytic plant known as resurrection plant or birds nest moss as it shows ball like appearence in dry season.

The main plant body of SelagineIla sp. is

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Gametophyte

  2. Sporophyte

  3. Both gametophyte and sporophyte

  4. Halophyte

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Correct Option: B
Explanation:

The main plant body of SelagineIla sp. is sporophyte which is diploid in condition.

Number of megaspore in Selaginella rupestris is

classification of pteridophytes kingdom plantae plant kingdom biology

  1. One

  2. Two

  3. Six

  4. Seven

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Correct Option: A
Explanation:

The four megaspores derived from a megaspore mother cell may not always be functional. i.e. In S.rupestris single megaspore is functional.

Selaginella and Salvinia are considered to represent a significant step towards evolution of seed habit because

classification of pteridophytes kingdom plantae plant kingdom biology

  1. Female gametophyte is free and gets dispersed like seeds

  2. Female gametophytes lack archegonia

  3. Megaspores possess endosperm and embryo surrounded by seed coat

  4. Embryo develops in female gametophyte which is retained on parent sporophyte

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Correct Option: D