Complete NCERT Solutions for CBSE Class 11 Biology Chapter 3 — all intext and chapter-end exercise questions on Algae, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms answered clearly.
Updated 11 June 20267 min read
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These are complete NCERT Solutions for CBSE Class 11 Biology Chapter 3 — Plant Kingdom. Attempt each question before checking. For plant classification questions, use correct group names and distinguishing features — marks are given for terms like 'gametophyte', 'sporophyte', 'archegonium', etc.
Key Concepts (Quick Recap)
Plant classification: Traditionally based on morphology, anatomy, and embryology; modern classification uses phylogenetic (evolutionary) relationships.
Algae are classified into three main classes based on the type of photosynthetic pigment present and the type of stored food: 1. Chlorophyceae (Green algae): Chlorophyll a and b; stored food is starch. 2. Phaeophyceae (Brown algae): Chlorophyll a and c, fucoxanthin (brown pigment); stored food is laminarin or mannitol. 3. Rhodophyceae (Red algae): Chlorophyll a and d, phycoerythrin (red pigment); stored food is floridean starch.
Q2. When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm, and an angiosperm?
Answer
Reduction division (meiosis) takes place during spore formation in all these groups:
Plant Group
When/Where Meiosis Occurs
Product
Liverwort
In the sporophyte — capsule of the sporangium
Spores (n)
Moss
In the sporophyte — capsule of the sporangium
Spores (n)
Fern
In the sporangia on the underside of sporophylls (fronds)
Spores (n)
Gymnosperm
In the microsporangia and megasporangia of the sporophyte
Microspores and megaspores (n)
Angiosperm
In the anthers (microsporogenesis) and ovules (megasporogenesis)
Pollen grains and embryo sac (n)
Q3. Name three groups of plants that bear archegonia. Briefly describe the life cycle pattern in any one of them.
Answer
The three groups that bear archegonia are: Bryophytes, Pteridophytes, and Gymnosperms.
Life cycle pattern in Bryophytes (e.g., Moss): The dominant phase is the gametophyte (n). The gametophyte has two stages: protonema (creeping, green, branched filament) and the leafy gametophore (erect leafy shoot bearing sex organs). The archegonium (female) produces the egg, and the antheridium (male) produces biflagellate sperm. Water is essential for fertilisation. After fertilisation, the zygote (2n) develops into a sporophyte consisting of foot, seta, and capsule. The capsule contains spores formed by meiosis. Spores germinate to form a new protonema, completing the cycle.
Page 40
Q1. How would you distinguish between a moss and a fern?
Answer
Feature
Moss (Bryophyte)
Fern (Pteridophyte)
Vascular tissue
Absent
Present (xylem and phloem)
True roots
Absent (rhizoids)
Present
True leaves
Absent (phyllids)
Present (fronds)
Dominant phase
Gametophyte
Sporophyte
Habitat
Moist, shady places; need water for fertilisation
Shady, damp places; also need water for fertilisation
Spore-bearing
Capsule on sporophyte
Sporangia on underside of fronds
Chapter-End Exercise
Q1. What is the basis of classification of algae?
Answer
(See Intext Page 28 Q1 — answered above.)
Q2. Name three groups of plants that bear archegonia. Briefly describe the life cycle pattern in any one of them.
Answer
(See Intext Page 28 Q3 — answered above.)
Q3. Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in a dicot; leaf cell of a moss; prothallus cell of a fern; meristem cell of a monocot; ovum of a liverwort; zygote of a fern.
Answer
Structure
Ploidy
Protonemal cell of a moss
Haploid (n)
Primary endosperm nucleus in a dicot
Triploid (3n)
Leaf cell of a moss
Haploid (n)
Prothallus cell of a fern
Haploid (n)
Meristem cell of a monocot
Diploid (2n)
Ovum of a liverwort
Haploid (n)
Zygote of a fern
Diploid (2n)
Q4. Why are bryophytes called the amphibians of the plant kingdom?
Answer
Bryophytes are called the amphibians of the plant kingdom because, like amphibians in the animal kingdom that live on land but need water for reproduction, bryophytes live on land but require water for fertilisation. The sperm (antherozoids) of bryophytes are flagellated and must swim through a film of water to reach the archegonium and fertilise the egg. Without water, sexual reproduction cannot occur.
Q5. Differentiate between the following:(i) Red algae and Brown algae
Answer
Feature
Red Algae (Rhodophyceae)
Brown Algae (Phaeophyceae)
Pigments
Chlorophyll a, d; phycoerythrin
Chlorophyll a, c; fucoxanthin
Stored food
Floridean starch
Laminarin, mannitol
Cell wall
Cellulose, pectin, polysulphates
Cellulose, algin
Flagella
Absent
Present (2 unequal, lateral)
Habitat
Mostly marine, deeper waters
Marine, cooler waters
Examples
Polysiphonia, Gelidium, Gracilaria
Fucus, Sargassum, Laminaria
(ii) Liverworts and Moss
Feature
Liverworts
Moss
Plant body
Thalloid or leafy (dorsoventral)
Erect, leafy gametophore
Leaves
Without midrib (if present)
With midrib
Rhizoids
Unicellular
Multicellular, branched
Capsule
Simpler, elaters present
Complex, peristome teeth present
Protonema
Short-lived
Conspicuous, long-lived
Examples
Marchantia, Riccia
Funaria, Polytrichum
(iii) Homosporous and Heterosporous
Feature
Homosporous
Heterosporous
Spore type
One type of spore (all similar)
Two types — microspores and megaspores
Spore size
All spores same size
Microspores small, megaspores large
Gametophyte
Bisexual (both male and female)
Unisexual — microspore → male, megaspore → female
Examples
Most ferns, bryophytes
Selaginella, Salvinia, all seed plants
Q6. How would you distinguish between monocots and dicots?
Answer
Feature
Monocots
Dicots
Cotyledons
One
Two
Leaf venation
Parallel
Reticulate
Root system
Fibrous
Taproot
Vascular bundles
Scattered in stem
In a ring in stem
Cambium
Absent
Present
Flower parts
In multiples of 3
In multiples of 4 or 5
Examples
Rice, wheat, maize, bamboo
Pea, rose, mango, sunflower
Q7. Describe the important characteristics of Gymnosperms.
Answer
1. Naked seeds: Seeds are not enclosed in a fruit; they are exposed on the surface of megasporophylls. 2. Vascular tissue present: Xylem and phloem are well-developed, but vessels are absent in xylem (except in Gnetum) and companion cells are absent in phloem. 3. Plant body: Well-differentiated into roots, stem, and leaves. Sporophyte is dominant. 4. Reproduction: Heterosporous — produce microspores (pollen grains) and megaspores. Pollination is by wind (anemophily). 5. Seeds: The megaspore develops into a multicellular female gametophyte that bears archegonia. Fertilisation produces a zygote that develops into an embryo within the seed. 6. Cones: Male (microsporangiate) and female (megasporangiate) cones are separate. 7. Examples:Pinus (pine), Cycas, Ginkgo, Gnetum.
Bryophytes are non-vascular, lack true roots/stems/leaves (have thallus body), and the dominant phase is the gametophyte. Pteridophytes are vascular, have true roots/stems/leaves, and the dominant phase is the sporophyte. Bryophytes are called amphibians of the plant kingdom because they need water for fertilisation, while pteridophytes also need water for sperm movement but have vascular tissue for conduction.
