This MCQ module is based on: NCERT Exercises and Solutions: Plant Kingdom
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NCERT Exercises and Solutions: Plant Kingdom
🎓 Class 11
Biology
CBSE
Theory
Ch 3 – Plant Kingdom
⏱ ~8 min
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NCERT Exercises and Solutions: Plant Kingdom
📋 Chapter Summary
Plant Kingdom — Key Takeaways
- Classification systems: Artificial (few characters, e.g., Linnaeus's sexual system) → Natural (totality of features, e.g., Bentham & Hooker) → Phylogenetic (evolutionary relationships, DNA-based).
- Algae: Chlorophyll-bearing, simple, thalloid, autotrophic, mostly aquatic. 3 classes — Chlorophyceae (green: starch/cellulose), Phaeophyceae (brown: mannitol+laminarin/algin), Rhodophyceae (red: floridean starch/polysulphate).
- Bryophytes: "Amphibians of plant kingdom." Gametophyte dominant. No vascular tissue. Sex organs multicellular (antheridium, archegonium). Liverworts (Marchantia) and Mosses (Funaria).
- Pteridophytes: First true vascular plants. Sporophyte dominant. Need water for fertilization (motile sperm). Most are homosporous; some heterosporous (Selaginella, Salvinia).
- Gymnosperms: Naked seeds (in cones, not fruits). Pollen tube — END of water dependence! Heterosporous. Examples: Cycas, Pinus, Ginkgo, Sequoia.
- Angiosperms: Flowering plants. Seeds in fruits. Double fertilization: 2n zygote + 3n endosperm. Two classes: Dicots (2 cotyledons, reticulate venation, tap root) and Monocots (1 cotyledon, parallel venation, fibrous root).
- Alternation of generations: Universal in plants — gametophyte (n) ↔ sporophyte (2n). Trend through evolution: gametophyte reduction + sporophyte dominance.
🔑 Key Terms
PhycologyStudy of algae
ThallusPlant body not differentiated into root, stem, leaf
IsogamyFusion of similar gametes
AnisogamyFusion of dissimilar-sized motile gametes
OogamyFusion of small motile sperm + large non-motile egg
AntheridiumMale sex organ (multicellular)
ArchegoniumFemale sex organ (flask-shaped)
GametophyteHaploid (n) sex-organ-bearing phase
SporophyteDiploid (2n) spore-producing phase
SporangiaSpore-producing structures
SoriClusters of sporangia (in ferns)
HeterosporyTwo spore types (mega + micro)
Pollen tubeCarries male gametes; ends water dependence
Double fertilization2n zygote + 3n endosperm; unique to angiosperms
Dicot2 cotyledons; reticulate venation
Monocot1 cotyledon; parallel venation
📝 NCERT Exercises (Worked Solutions)
Exercise 1
What is the basis of classification of algae?
Algae are classified into 3 main classes — Chlorophyceae (green), Phaeophyceae (brown), Rhodophyceae (red) — based on:
- Major photosynthetic pigments: Chlorophyll a, b (Chlorophyceae); fucoxanthin (Phaeophyceae); phycoerythrin (Rhodophyceae).
- Reserve food materials: Starch, mannitol/laminarin, floridean starch respectively.
- Cell wall composition: Cellulose; cellulose+algin; cellulose+pectin+polysulphate esters.
- Number, position, and type of flagella on motile cells (zoospores or gametes).
Exercise 2
When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?
In all land plants, meiosis (reduction division) occurs during spore formation in the sporophyte. Specifically:
| Plant | Where meiosis occurs |
|---|---|
| Liverwort | In the capsule of the sporophyte (spore mother cells → spores) |
| Moss | In the capsule of the sporophyte (spore mother cells → spores) |
| Fern | In the sporangia on sporophylls of sporophyte (spore mother cells → spores) |
| Gymnosperm | In microsporangia (microspores) and megasporangia (megaspores) of cones |
| Angiosperm | In the anthers (microspores → pollen) and ovules (megaspores → embryo sac mother cell) |
Exercise 3
Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.
Three groups bearing archegonia: Bryophytes, Pteridophytes, and Gymnosperms.
Life cycle of a Moss (bryophyte):
Life cycle of a Moss (bryophyte):
- Spore (n) germinates → filamentous protonema (n).
- Protonema produces buds → leafy gametophyte (n) — dominant phase.
- Gametophyte develops antheridia (♂) and archegonia (♀) at apex.
- Antherozoids swim through water → enter archegonium → fertilize egg.
- Zygote (2n) → divides by mitosis → multicellular sporophyte (2n) with foot, seta, capsule.
- Spore mother cells in capsule undergo MEIOSIS → haploid spores.
- Spores released, germinate → cycle restarts.
Exercise 4
Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a fern; gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort, and zygote of a fern.
| Cell / Structure | Ploidy | Reason |
|---|---|---|
| Protonemal cell of moss | n (haploid) | Part of gametophyte |
| Primary endosperm nucleus (PEN) in dicot | 3n (triploid) | Result of double fertilization (sperm n + 2 polar nuclei n+n) |
| Leaf cell of moss | n (haploid) | Part of leafy gametophyte |
| Prothallus cell of fern | n (haploid) | Prothallus = gametophyte |
| Gemma cell in Marchantia | n (haploid) | Asexual bud on gametophyte |
| Meristem cell of monocot | 2n (diploid) | Part of sporophyte (the plant body) |
| Ovum of liverwort | n (haploid) | Female gamete |
| Zygote of fern | 2n (diploid) | Result of fertilization (n + n = 2n) |
Exercise 5
Write a note on economic importance of algae and gymnosperms.
Economic Importance of Algae:
- Photosynthesis & oxygen: Algae fix at least 50% of total CO₂ on Earth — major oxygen producers.
- Food: 70+ marine algal species used as food: Porphyra (nori for sushi), Laminaria, Sargassum.
- Hydrocolloids: Agar (from Gelidium, Gracilaria) — culture media, ice creams, jellies. Alginic acid (from brown algae) — food thickener. Carrageenan (from Chondrus crispus) — milk products.
- Food supplements: Chlorella and Spirullina — protein-rich, used by space travellers.
- Iodine: Marine algae like Laminaria are a commercial source.
- Timber: Pine, deodar, fir, spruce — major commercial wood.
- Paper: Most paper pulp comes from gymnosperm trees.
- Resin and turpentine: From pines.
- Tannins: From bark of gymnosperms — used in leather industry.
- Edible parts: Pinus gerardiana seeds (chilgoza nuts).
- Medicines: Ephedra yields ephedrine (decongestant). Taxus brevifolia yields taxol (anti-cancer).
- Ornamentals: Cycas, Thuja, Araucaria in landscaping.
Exercise 6
Both gymnosperms and angiosperms bear seeds, then why are they classified separately?
Although both bear seeds, they differ in many fundamental ways:
Conclusion: The differences are too fundamental to merge them. Angiosperms represent a distinct evolutionary lineage with the flower as a defining innovation.
| Feature | Gymnosperms | Angiosperms |
|---|---|---|
| Seed exposure | Naked (exposed on cone scales) | Enclosed in fruit |
| Flowers | Absent (only cones) | Present |
| Ovary | Absent | Present |
| Fruit | Absent | Present (develops from ovary) |
| Fertilization | Single | Double (unique!) |
| Endosperm | Haploid (n), pre-fertilization | Triploid (3n), post-fertilization |
| Vessels in xylem | Absent (only tracheids; exception: Ephedra) | Present |
| Companion cells in phloem | Absent | Present |
Exercise 7
What is heterospory? Briefly comment on its significance. Give two examples.
Heterospory: The phenomenon of producing two distinct types of spores: microspores (small, develop into male gametophytes) and megaspores (large, develop into female gametophytes).
Significance:
Significance:
- Evolution toward seeds: Heterospory is considered the evolutionary precursor to the seed habit. Megaspore retention on the parent plant + female gametophyte development within parent tissue → eventually evolved into the ovule and then seed.
- Sexual differentiation: Establishes male/female differentiation at the spore level itself.
- Parental nutrition: Megaspore retention allows parental investment in offspring.
- Better protection: Female gametophyte protected within megasporangium.
Exercise 8
Explain briefly the following terms with suitable examples: (i) protonema (ii) antheridium (iii) archegonium (iv) diplontic (v) sporophyll (vi) isogamy.
(i) Protonema: The first filamentous stage in the development of moss gametophyte from a spore. Creeping, branched, green, alga-like. Buds on protonema develop into the leafy gametophyte. Example: in Funaria.
(ii) Antheridium: Multicellular male sex organ in bryophytes, pteridophytes, and gymnosperms. Produces motile, biflagellate male gametes (antherozoids). Example: present at the apex of leafy moss shoots.
(iii) Archegonium: Multicellular, flask-shaped female sex organ in bryophytes, pteridophytes, gymnosperms. Produces a single egg at its base (venter). Example: present in Marchantia, Funaria, Cycas.
(iv) Diplontic: A life cycle where the sporophyte (2n) is the dominant, photosynthetic, free-living phase, and the gametophyte (n) is reduced and dependent on sporophyte. Example: all seed plants (gymnosperms and angiosperms). The reverse is haplontic (most algae).
(v) Sporophyll: A modified leaf bearing or subtending sporangia. May form clusters called strobili or cones. Examples: pine cone scales (megasporophylls), fern leaves with sori on undersides, stamens and carpels of flowers.
(vi) Isogamy: Sexual reproduction where the two fusing gametes are similar in size, shape, and behavior. The gametes may both be motile or both non-motile. Examples: Spirogyra (non-motile isogametes), some species of Chlamydomonas (motile isogametes).
(ii) Antheridium: Multicellular male sex organ in bryophytes, pteridophytes, and gymnosperms. Produces motile, biflagellate male gametes (antherozoids). Example: present at the apex of leafy moss shoots.
(iii) Archegonium: Multicellular, flask-shaped female sex organ in bryophytes, pteridophytes, gymnosperms. Produces a single egg at its base (venter). Example: present in Marchantia, Funaria, Cycas.
(iv) Diplontic: A life cycle where the sporophyte (2n) is the dominant, photosynthetic, free-living phase, and the gametophyte (n) is reduced and dependent on sporophyte. Example: all seed plants (gymnosperms and angiosperms). The reverse is haplontic (most algae).
(v) Sporophyll: A modified leaf bearing or subtending sporangia. May form clusters called strobili or cones. Examples: pine cone scales (megasporophylls), fern leaves with sori on undersides, stamens and carpels of flowers.
(vi) Isogamy: Sexual reproduction where the two fusing gametes are similar in size, shape, and behavior. The gametes may both be motile or both non-motile. Examples: Spirogyra (non-motile isogametes), some species of Chlamydomonas (motile isogametes).
Exercise 9
Differentiate between: (i) red algae and brown algae (ii) liverworts and moss (iii) homosporous and heterosporous pteridophyte.
(i) Red algae vs Brown algae:
(ii) Liverworts vs Moss:
(iii) Homosporous vs Heterosporous pteridophytes:
| Feature | Red algae (Rhodophyceae) | Brown algae (Phaeophyceae) |
|---|---|---|
| Major pigment | Phycoerythrin | Fucoxanthin |
| Reserve food | Floridean starch | Mannitol, laminarin |
| Cell wall | Cellulose + polysulphate esters | Cellulose + algin |
| Flagella | Absent | Two unequal lateral flagella (on motile cells) |
| Examples | Polysiphonia, Porphyra, Gracilaria | Ectocarpus, Sargassum, Laminaria, Fucus |
| Feature | Liverworts | Moss |
|---|---|---|
| Body | Thalloid or leafy (dorsiventral) | Differentiated into stem and leaves |
| Protonema | Absent | Present (alga-like filamentous stage) |
| Asexual reproduction | Fragmentation, gemmae in gemma cups | Fragmentation, buds on protonema |
| Sporophyte | Simple (foot, seta, capsule); seta sometimes absent | More elaborate; capsule with peristome teeth |
| Examples | Marchantia, Riccia, Pellia | Funaria, Polytrichum, Sphagnum |
| Feature | Homosporous | Heterosporous |
|---|---|---|
| Spore types | One type only | Two types (microspore + megaspore) |
| Gametophyte | Bisexual (one type) | Two unisexual gametophytes (male + female) |
| Megaspore retention | Spores dispersed; gametophyte free-living | Megaspore often retained on parent |
| Examples | Most ferns, Equisetum, Lycopodium | Selaginella, Salvinia |
| Evolutionary significance | Ancestral condition | Precursor to seed habit |
Exercise 10
Match the following (column I with column II):
(a) Chlamydomonas (i) Moss
(b) Cycas (ii) Pteridophyte
(c) Selaginella (iii) Algae
(d) Sphagnum (iv) Gymnosperm
| Column I | Column II | Match |
|---|---|---|
| (a) Chlamydomonas | (iii) Algae | Unicellular green alga (Chlorophyceae) |
| (b) Cycas | (iv) Gymnosperm | Naked-seed plant; ovules on megasporophylls |
| (c) Selaginella | (ii) Pteridophyte | Heterosporous pteridophyte with microphylls |
| (d) Sphagnum | (i) Moss | Bryophyte (peat moss) |
Exercise 11
Describe the important characteristics of gymnosperms.
Important characteristics of gymnosperms:
- Naked seeds: Ovules are NOT enclosed by an ovary wall. Seeds remain exposed on cone scales (megasporophylls). The defining feature.
- Vascular plants: Have well-developed xylem (only tracheids; vessels absent except in Ephedra) and phloem (no companion cells).
- Sporophyte dominant: The plant body is the sporophyte (2n); gametophytes are reduced.
- Heterosporous: Produce microspores (→ pollen) and megaspores (→ ovule).
- Cones (strobili): Reproductive structures. Male strobili bear microsporophylls; female strobili bear megasporophylls.
- Pollen tube: Carries male gametes to ovule — eliminates need for water in fertilization.
- Wind pollination: Massive pollen production; no flower attractants needed.
- Endosperm: Haploid (n) — formed from female gametophyte BEFORE fertilization.
- Reduced gametophytes: Female gametophyte develops within megasporangium; male gametophyte = highly reduced pollen grain.
- Long-lived: Many gymnosperms are perennial trees (some living thousands of years).
- Adaptations to extreme environments: Needle-like leaves, thick cuticle, sunken stomata to reduce water loss.
- Examples: Cycas, Pinus, Cedrus, Ginkgo, Sequoia, Ephedra, Taxus.
🎓 Chapter 3 Complete! You've now traced the entire evolutionary journey of plants — from simple algae through bryophytes, pteridophytes, and gymnosperms to flowering plants. Each group represents key innovations that solved real ecological problems. Next chapter (Animal Kingdom) will take a similar evolutionary tour through animals!
🔬 Interactive: Identify the Class of Algae
Choose the three diagnostic characters and the key will name the class.
Class
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Examples
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Frequently Asked Questions - NCERT Exercises and Solutions: Plant Kingdom
What are the most-asked NCERT exercise questions in Chapter 3 Plant Kingdom?
NCERT Class 11 Biology Chapter 3 Plant Kingdom exercises cover definitions, classification, structure-function relationships, labelled diagrams, and application-based questions. The MyAiSchool exercise set provides full step-by-step solutions for every NCERT question, aligned with the CBSE board exam pattern. Students should master scientific terminology, diagram labelling, and concept comparison tables to score full marks.
How should students approach labelled diagram questions in Plant Kingdom?
For labelled diagram questions in NCERT Class 11 Biology Chapter 3 Plant Kingdom: (1) draw a clean, large, proportional diagram with sharp pencil lines, (2) label each part with horizontal lines on the right or left side, (3) use scientific terminology (Latin/Greek names where applicable), (4) write a 1-2 line description below if asked. The MyAiSchool solutions provide editable reference diagrams aligned with NCERT textbook figures.
What types of CBSE board questions come from Chapter 3?
CBSE Class 11 Biology board questions from Chapter 3 (Plant Kingdom) typically include: (1) 1-mark MCQs on definitions and classification, (2) 2-mark short-answers on structure-function or comparisons, (3) 3-mark labelled-diagram questions, (4) 5-mark long-answer essays combining diagram + description + significance. The MyAiSchool exercise set tags each question by mark weight and Bloom level (L1-L6).
How do I compare two biological concepts in 5-mark questions?
For 5-mark comparison questions in NCERT Class 11 Biology Chapter 3: (1) use a two-column table with feature headings down the left side, (2) compare on at least 5-6 features (structure, function, location, examples, significance), (3) include one labelled diagram if relevant, (4) end with one line on biological significance. The MyAiSchool solutions follow this CBSE-aligned tabular format consistently for full marks.
What are common mistakes in Chapter 3 exercises?
Common mistakes in NCERT Class 11 Biology Chapter 3 (Plant Kingdom) include: (1) confusing similar scientific names or terminology, (2) skipping diagram labels or drawing too small, (3) missing examples in classification questions, (4) writing essay-style answers when a table is expected, (5) forgetting to mention biological significance. The MyAiSchool solutions highlight these traps so students avoid losing marks unnecessarily.
How does the MyAiSchool solution differ from other NCERT solution sets?
MyAiSchool Class 11 Biology Chapter 3 Plant Kingdom solutions use NEP 2024-aligned pedagogy with Bloom Taxonomy tagged questions (L1 Remember to L6 Create), step-by-step working with biological reasoning, fully labelled SVG diagrams, comparison tables, interactive simulations, and Competency-Based Questions (CBQs) for board exam practice. Each solution is verified against NCERT textbook and CBSE marking schemes.
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