Plant Kingdom — Class 11 MCQs with Answers

Plant Kingdom — important questions & MCQs with answers (Class 11 Biology)

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

1. Q1 of 6Easy

   Spirogyra is a:

   AFungusBGreen algaCBryophyteDGymnosperm
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   Answer: Green alga

   Explanation: Spirogyra is a filamentous freshwater green alga (Chlorophyceae) with helical chloroplasts — not a fungus (no chlorophyll), a bryophyte (no thallus differentiation) or a gymnosperm (no seeds).

2. Q2 of 6Easy

   Kingdom Plantae includes all of the following EXCEPT:

   AAlgaeBBryophytesCFungiDAngiosperms
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   Answer: Fungi

   Explanation: Kingdom Plantae covers algae, bryophytes, pteridophytes, gymnosperms and angiosperms — all photosynthetic eukaryotes. Fungi are heterotrophic and lack chlorophyll, so they sit in a separate kingdom.

3. Q3 of 6Medium

   Haplontic life cycle is found in:

   A*Spirogyra* (most algae)BAngiospermsCGymnospermsDPteridophytes
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   Answer: *Spirogyra* (most algae)

   Explanation: A haplontic life cycle keeps the haploid gametophyte dominant, with the zygote as the only diploid cell, which undergoes meiosis immediately — typical of most algae such as Spirogyra.

4. Q4 of 6Medium

   First land plants with vascular tissue:

   APteridophytes (ferns)BBryophytesCAngiospermsDAlgae
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   Answer: Pteridophytes (ferns)

   Explanation: Pteridophytes (ferns, Selaginella) are the first plants to evolve true xylem and phloem, unlike bryophytes which lack vascular tissue and rely on simple parenchyma for conduction.

5. Q5 of 6Hard

   Assertion: Bryophytes do not have true vascular tissue. Reason: They lack xylem and phloem.

   AA false, R trueBBoth A and R true; R does not explain ACA true, R falseDBoth A and R true; R explains A
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   Answer: Both A and R true; R explains A

   Explanation: Bryophytes truly lack lignified xylem and phloem, so water and food move through simple, undifferentiated tissue instead of true vascular bundles — the reason correctly explains the assertion.

6. Q6 of 6Hard

   In angiosperms, the dominant phase is:

   ANeitherBGametophyteCBoth equallyDSporophyte (diploid)
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   Answer: Sporophyte (diploid)

   Explanation: In angiosperms the diploid sporophyte is the dominant, visible plant body; the gametophyte is reduced to a tiny embryo sac and pollen grain — the reverse of the bryophyte pattern.

Plant Kingdom notes: key concepts (Class 11 Biology)

The plant kingdom runs from simple thalloid algae to complex flowering plants, a series marked by the rise of vascular tissue, seeds and flowers. Central to it is alternation of generations — the haploid gametophyte and diploid sporophyte — whose relative dominance shifts as land adaptation increases.

Algae

Chlorophyll-bearing, simple thalloid autotrophs, mostly aquatic. Reproduce vegetatively, asexually by spores, or sexually — isogamous, anisogamous or oogamous.

Classes of algae

Chlorophyceae (green; chlorophyll a, b), Phaeophyceae (brown; fucoxanthin) and Rhodophyceae (red; r-phycoerythrin) — the pigment sets them apart.

Stored food in algae

Green algae store starch, brown algae store laminarin and mannitol, red algae store floridean starch. Agar, algin and carrageenan are algal products.

Bryophytes

'Amphibians of the plant kingdom' (mosses, liverworts) — live on land but need water for sperm to reach the egg. Lack true roots, stems and vascular tissue.

Bryophyte life cycle

The dominant, photosynthetic phase is the haploid gametophyte; the diploid sporophyte is short-lived and dependent on it for nutrition.

Pteridophytes

First true vascular land plants (ferns, horsetails, Selaginella) with roots, stems and leaves; sporophyte dominant, yet still need water for fertilisation.

Homospory & heterospory

Most pteridophytes are homosporous; a few like Selaginella and Salvinia are heterosporous, making micro- and megaspores — a precursor to the seed habit.

Gymnosperms

Naked-seeded plants (conifers, cycads, Ginkgo); ovules are not enclosed in an ovary and seeds not in a fruit. Have well-developed vascular tissue.

Gymnosperm features

They are heterosporous; male and female cones bear micro- and megasporophylls. Pinus and Cycas are examples; Cycas roots host N-fixing cyanobacteria.

Angiosperms

Flowering plants whose seeds are enclosed in a fruit from the ovary. Range from tiny Wolffia to tall Eucalyptus; divided into monocots and dicots.

Double fertilisation

Unique to angiosperms: one male gamete fuses with the egg (syngamy → zygote), the other with two polar nuclei (triple fusion → 3n endosperm).

Alternation of generations

The cycle alternates a haploid gametophyte with a diploid sporophyte. Meiosis in spore formation and gamete fusion link the two phases together.

Haplontic vs diplontic

Haplontic (many algae): gametophyte dominant, sporophyte just a zygote. Diplontic (seed plants): sporophyte dominant, gametophyte greatly reduced.

Haplo-diplontic

An intermediate pattern in bryophytes and pteridophytes — both a multicellular haploid and a multicellular diploid body alternate within one cycle.